Carbon dioxide detection in biological systems
Theo Murphy meeting organised by Professor Martin Cann, Professor Elizabete Carmo-Silva and Dr Eoin Cummins.
Carbon dioxide is essential for life. It is central to physiological processes, including photosynthesis, metabolism, homeostasis, and chemosensing. However, the mechanisms underpinning carbon dioxide sensing, signalling and adaptation are poorly understood. This meeting will unite researchers who study carbon dioxide biology in photosynthetic and animal systems to discuss the common goal of understanding the molecular basis of carbon dioxide detection.
Poster session
There will be a poster session on Monday 18 November. If you would like to present a poster, please submit your proposed title, abstract (up to 200 words), author list, and the name of the proposed presenter and institution to the Scientific Programmes team no later than Friday 20 September 2024.
Attending the meeting
This event is intended for researchers in relevant fields, and is a residential meeting taking place at Holiday Inn Manchester City Centre.
- Free to attend
- Advance registration essential (more information about registration will be available soon)
- This is an in-person meeting
- Catering options are available to purchase during registration. Participants are responsible for their own accommodation booking
Enquiries: contact the Scientific Programmes team
Organisers
Schedule
Chair
Dr Eoin Cummins, University College Dublin, Ireland
Dr Eoin Cummins, University College Dublin, Ireland
Dr Cummins holds a BSc in Pharmacology and a PhD in molecular medicine. He is currently an Associate Professor in Physiology in the School of Medicine, University College Dublin.
The Cummins lab focuses on the role of physiological gases eg Oxygen (O2) and carbon dioxide (CO2), in the context of health and disease. It is well known that areas of hypoxia (low O2) exist in regions of altered metabolic activity, ischemia, inflammation and cancer. Similarly, in areas with depleted oxygen, cellular and tissue carbon dioxide levels can rise, resulting in hypercapnia. The concentrations of these physiological gases are known to impact on cellular signaling and modify proliferative, healing and immune/ inflammatory responses. Current work in the Cummins lab is focused on understanding the contribution of carbon dioxide to metabolic signalling in immune cells and skeletal muscle.
09:00-09:05 |
Welcome by the Royal Society and lead organiser
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09:05-09:30 |
Carbon dioxide-mediated post-translational modifications
Carbon dioxide is essential for life. It is at the beginning of every life process as a substrate of photosynthesis. It is at the end of every life process as the product of post-mortem decay. Therefore, it is not surprising that this gas regulates such diverse processes as cellular chemical reactions, transport, maintenance of the cellular environment, and behaviour. Carbon dioxide is a strategically important research target relevant to crop responses to environmental change, insect vector-borne disease and public health. However, we know little of carbon dioxide’s direct interactions with the cell. The carbamate post-translational modification, mediated by the nucleophilic attack by carbon dioxide on N-terminal α-amino groups or the lysine ɛ-amino groups, is one mechanism by which carbon dioxide might alter protein function to form part of a sensing and signalling mechanism. Here, we describe recent studies on new techniques to isolate this problematic post-translational modification and the modification’s functional consequences. Professor Martin Cann, Durham University, UK
Professor Martin Cann, Durham University, UKProfessor Cann’s core interests are in molecular mechanisms for inorganic carbon sensing. He has been part of teams that have made several foundational discoveries in this field. These include the discovery of the mammalian soluble adenylyl cyclase and its inorganic carbon regulation. This finding represented the first observation of a signalling molecule binding and responding to environmental inorganic carbon. He also contributed the finding that signalling molecules can be directly responsive to carbon dioxide, the molecular basis of carbon dioxide-regulated anion transport, the contribution of carbon dioxide to light-harvesting regulation in cyanobacteria, and new technology for discovering carbon dioxide-mediated post-translational modifications. |
09:30-09:45 |
Discussion
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09:45-10:15 |
Title TBC
Dr Lorna McAusland, University of Nottingham, UK
Dr Lorna McAusland, University of Nottingham, UKDr Lorna McAusland is a plant physiologist (pronouns she/her), specialising in the dynamic responses of photosynthesis and water regulation to heat stress. Currently hosted by Professor Erik Murchie’s lab at the University of Nottingham (UK), Lorna was recently awarded a BBSRC-Discovery Fellowship; working on development of high-throughput systems to assess non-foliar photosynthesis under heat. |
10:15-10:30 |
Discussion
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10:30-11:00 |
Break
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11:00-11:30 |
Chemical techniques to image and monitor CO2 at the cellular level
Understanding the complex interactions between carbon dioxide and cellular signalling pathways continues to pose a significant challenge due to the absence of methodologies enabling the visualisation of carbon dioxide at the cellular scale. In this lecture, recent advancements in CO2 molecular sensing and imaging are presented. These techniques rely on the Staudinger-Aza-Wittig reaction, in which an iminophosphorane serves as a selective CO2 responsive trigger. By coupling this moiety to fluorescent scaffolds, a series of fluorescent carbon dioxide sensors were generated with diverse optical properties. The design, synthesis, and evaluation of these sensors are described along with new imaging opportunities. Dr Ori Green, Technion- Israel Institute of Technology, Israel
Dr Ori Green, Technion- Israel Institute of Technology, IsraelOri Green completed his undergraduate studies at Tel-Aviv University in 2014, earning his Bachelor of Science in Chemistry. Continuing his academic journey, Ori pursued both his MSc and PhD degrees in Organic Chemistry at Tel-Aviv University, under the guidance of Professor Doron Shabat. In April 2020, he started a postdoctoral position at ETH Zurich, Switzerland, under the mentorship of Professor Bill Morandi, where he explored new horizons in reaction development and chemical methodologies. He was honoured with the “Jortner Prize” award and was granted the International Human Frontier Science Program postdoctoral fellowship and Rothschild Fellowship. With a strong interest in the interface of chemistry with biology, Ori’s research program focuses on strategies for visualising and sensing elusive analytes and developing techniques for chemical post-transitional modification. In March 2024, he started his independent career as an Assistant Professor at Technion, Haifa, Israel (Israel Institute of Technology). |
11:30-11:45 |
Discussion
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11:45-12:15 |
Translational aspects of CO2 signalling in the lung
Several acute and chronic lung diseases, eg acute respiratory distress syndrome (ARDS) and chronic obstructive pulmonary disease (COPD) are associated with alveolar hypoventilation leading to hypercapnia and worse outcomes. Hypercapnia, similar to hypoxia, is a fundamental gas exchange disturbance, however, in contrast to hypoxia, the biological effects of hypercapnia remain largely under investigated. It is increasingly evident that elevated CO2 levels are primarily deleterious, contributing to various acute and chronic pulmonary disease states. The goal of our research is to enhance our understanding of the basic and translational aspects of CO2 sensing and signalling in the lung in health and disease, and to establish minimally invasive methodologies to eliminate excess CO2 in patients with hypercapnic respiratory failure. Ultimately, we aim to establish novel, selective, tailored therapy options, directly delivered to the lung to specifically interfere with hypercapnia-induced deleterious pulmonary signals. Professor István Vadász, Justus Liebig University Giessen, Germany
Professor István Vadász, Justus Liebig University Giessen, GermanyProfessor Vadász is vice chair of the Department of Internal Medicine and head of the Medical Intensive Care Unit at Justus Liebig University Giessen, Germany and Adjunct Associate Professor at the Division of Pulmonary and Critical Care Medicine at Northwestern University in Chicago, USA. The Vadász lab has significantly contributed to the understanding of the detrimental consequences of hypercapnia (accumulation of CO2 in blood and tissue) on basic biological phenomena, including dysfunction of the alveolar epithelial barrier, the primary site of CO2 elimination. More recently, the group of Professor Vadász has been focusing on the mechanisms of CO2 signalling in the lung and on specific hypercapnia-induced maladaptive events, as well as on novel minimally invasive technologies to eliminate excess CO2 in patients with hypercapnic respiratory failure. |
12:15-12:30 |
Discussion
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Chair
Professor Martin Cann, Durham University, UK
Professor Martin Cann, Durham University, UK
Professor Cann’s core interests are in molecular mechanisms for inorganic carbon sensing. He has been part of teams that have made several foundational discoveries in this field. These include the discovery of the mammalian soluble adenylyl cyclase and its inorganic carbon regulation. This finding represented the first observation of a signalling molecule binding and responding to environmental inorganic carbon. He also contributed the finding that signalling molecules can be directly responsive to carbon dioxide, the molecular basis of carbon dioxide-regulated anion transport, the contribution of carbon dioxide to light-harvesting regulation in cyanobacteria, and new technology for discovering carbon dioxide-mediated post-translational modifications.
13:30-14:00 |
Rubisco carbamylation and carboxylation
Rubisco catalyses the assimilation of CO2 into triose-phosphate intermediates of the Calvin-Benson-Bassham (CBB) cycle. To be catalytically competent, Rubisco must first be carbamylated by the binding of a separate CO2 molecule to lysine-201 in the catalytic site. This carbamate is stabilised by, and necessary for, the subsequent binding of a Mg2+ ion. Once activated through carbamylation and Mg2+ binding, the enzyme can catalyse either the carboxylation or oxygenation of the sugar-phosphate substrate ribulose-1,5-bisphosphate (RuBP). In a plant leaf, the activity of Rubisco is dependent on the chloroplast environment, including the availability of CO2 and Mg2+ as well as the pH, which affects the affinity of the amine group of lysine-201 for binding CO2 and forming the carbamate. These conditions can be manipulated in the test tube during in vitro assays for determining the carbamylation status of Rubisco in the leaf at the time of sampling. On the other hand, the environmental conditions experienced by the leaf prior to sampling will affect its carbamylation status, and therefore the measurable rate of carboxylation and/or oxygenation. The role of other chloroplast components such as Rubisco’s catalytic chaperone, Rubisco activase, in modulating carbamylation will also be discussed during the talk given its influence on CO2 assimilation by Rubisco. Professor Elizabete Carmo-Silva, Lancaster University, UK
Professor Elizabete Carmo-Silva, Lancaster University, UKElizabete is an expert on the regulation of carbon assimilation by Rubisco in crop plants, especially wheat and cowpea. She leads a research team that aims to understand and improve the efficiency of photosynthesis to optimise the sustainability and climate resilience of crop production. She received her undergraduate degree in applied plant biology at the University of Lisbon, where she went on to earn her PhD researching photosynthesis and photorespiration in C4 grasses. She specialised on the regulation of Rubisco by its molecular chaperone Rubisco activase as a postdoctoral researcher with the USDA-ARS, then started exploring this knowledge for crop improvement as a research scientist at Rothamsted Research. She moved to Lancaster University in 2015 to start a research group that focuses on Rubisco regulation in crops. |
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14:00-14:15 |
Discussion
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14:15-14:45 |
Carbon dioxide and connexins: an evolving story
Connexins are ion channels, and homologues are found in vertebrates throughout evolution from lungfish, through reptiles and amphibians to mammals and birds. They are integral membrane proteins that exist as hexameric hemichannels, regulating cell homeostasis. Two adjacent cells’ hemichannels can interact to form dodecameric gap junctions, allowing direct transfer of ions between cells when opened. Connexin 26 (GJB2, hCx26) is one of 20 connexin gap junction family members identified in humans. hCx26 is physiologically important, with mutations causing a number of syndromes, amongst which Vohwinkel Syndrome, and Keratitis Ichthysosis Deafness syndrome (KID syndrome) are the most clinically significant. The activity of hCx26 is known to be regulated by the partial pressure of CO2. Through extensive mutagenesis studies in combination with functional measurements, it has been hypothesised that this regulation is through the carbamylation of a lysine on the intracellular loop of hCx26. Structural studies using cryo-EM have demonstrated the effect of CO2 on the structure. In the hexameric arrangement of the hemichannel the N-termini of the six connexin subunits fold in the centre of the protein, with the exact position controlling the aperture of the pore. Using a bicarbonate buffering system under high CO2 conditions the N-termini form a more constricted channel than under low CO2 conditions. The position of the intracellular loop on which the carbamylated lysine is situated influences the position of the N-terminus, thus controlling the function of the channel. The latest structural data will be discussed. Dr Deborah Brotherton, University of Warwick, UK
Dr Deborah Brotherton, University of Warwick, UKFollowing her PhD in structural biochemistry at the University of Cambridge, Debs explored the biochemistry and cell biology of DNA replication and cell division, working on new chemical entities to treat cancer and inflammation in industry. Transitioning back to both academia and structural studies in 2012 at the Structural Genomics Consortium, she began to work on integral membrane proteins at the University of Warwick in 2014. Since 2015, these studies have centred on structural and biophysical studies of ion channels and receptors that bind to, and are modified by carbon dioxide. Her experiments have resulted in multiple high resolution cryo-EM structures of connexin 26 that are clarifying the mechanism by which these channels open and close in response to carbon dioxide. |
14:45-15:00 |
Discussion
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15:00-15:30 |
Break
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15:30-16:00 |
CO2 sensitive mechanisms governing plant membrane trafficking machinery
CO2 is a substrate for photosynthesis, and it is acquired through microscopic pores called ‘stomata’ in exchange for transpirational water loss. Plants respond to elevated CO2 through short-term adjustments in stomatal movements and by adapting stomatal development over the long-term. Membrane vesicle traffic partakes in stomatal control by regulating osmotic ion transport through selective addition and removal of transport proteins, and it facilitates membrane plasticity to support reversible changes in cell volume. Despite the wealth of knowledge about stomata CO2 control of plant membrane trafficking machinery is an enigma. Using approaches in molecular cell biology, stomatal physiology and membrane biochemistry we tested CO2-sensitive membrane trafficking and its co-ordination of ion transport. We are very excited by the findings which suggest a new role for membrane trafficking proteins in CO2 sensing. Dr Rucha Karnik, University of Glasgow, UK
Dr Rucha Karnik, University of Glasgow, UKRucha is a cell biologist interested in the overarching mechanics of how plants coordinate growth with environmental cues. She uncovered components of the hormone-regulated vesicle trafficking machinery in plants that regulates primary transporters which energise plant growth and is now extending this work to understand how these pathways governing plant growth overlap with disease immunity. Rucha studies how plants sense and respond to climate challenges in the context of global warming and rising levels of atmospheric carbon dioxide. This includes the regulation of stomata, the microscopic pores on plants which mediate plant exchanges with their environment to dictate carbon and water cycles of the Earth. Plants responses to CO2 include immediate adjustments to stomatal movements and developmental changes in stomatal density and patterning on the leaf surface over longer times. This research is essential to develop new strategies to enhance crop productivity and safeguard agriculture against climate challenges. Going beyond her work in the laboratory, Rucha leads Sci-Seedlets, a cross-disciplinary Plant science education project, aiming to inspire the next generation of plant scientists through work in the classroom. Rucha has built this scheme to support primary schools, teachers, and educators with resources that combine traditional paper-based, interactive experimental and virtual gamification to provide tasters for plant science research for enhanced educational outcomes. Sci-Seedlets resources promote concepts of equality, diversity and inclusion in STEM and are now being expanded for use in secondary, undergraduate, and postgraduate teaching. |
16:15-16:45 |
Elevated CO2-induced methylation and downregulation of immune and antiviral genes is mediated by the transcription factor Zfhx3 in alveolar macrophages
Hypercapnia is associated with poor outcomes of pulmonary infection and advanced lung disease. Elevated CO2 downregulates immune and antiviral gene expression in macrophages and increases viral replication and mortality in mice infected with influenza A (IAV). These effects are reversed by blocking the zinc finger homeodomain transcription factor, Zfhx3, or Akt in alveolar macrophages (AM). Interestingly, Akt activation increases expression of the DNA methyltransferase, Dnmt3a, which mediates methylation-associated transcriptional silencing. In this study, the authors explored the role of Dnmt3a and DNA methylation in hypercapnia-induced suppression of immune and antiviral gene expression, and whether myeloid Zfhx3 deficiency protects against CO2 effects on Dnmt3a expression and DNA methylation. They also studied the effect of the methyltransferase inhibitor DAC on the hypercapnia-induced increase in viral replication and mortality of mice infected with IAV. Results: AM from hypercapnic control mice exhibited increased DNA methylation, and immune genes were most highly targeted. Hypercapnia-induced DNA methylation was attenuated in Zfhx3-deficient AM. Hypercapnia increased Dnmt3a expression in AM from control mice, and this effect was abrogated in AM from myeloid Zfhx3-deficient mice. DAC blocked the hypercapnia-induced increase in viral proteins and protected against hypercapnia-induced mortality in mice infected with IAV. Conclusions: Hypercapnic suppression of antiviral host defence is mediated, at least in part, by CO2-induced increases in Dnmt3a expression and methylation of immune and antiviral genes in AM. These effects are mediated by Zfhx3, previously unknown as an immunomodulator. Inhibiting DNA methylation is a potential therapeutic strategy to improve antiviral host defence in patients with hypercapnia. Dr Marina Casalino-Matsuda, Northwestern University, USA
Dr Marina Casalino-Matsuda, Northwestern University, USAMarina Casalino-Matsuda studied biochemistry at the National University of Cordoba, Argentina, where she also completed her PharmaD and PhD studies. She joined the Sporn research group in the Division of Pulmonary and Critical Care Medicine at Northwestern University in February 2012. Since that time, she has been studying with great interest the effects of hypercapnia on innate immunity and host defence in human and mouse macrophages and epithelial cells. She is extremely enthusiastic about continuing her work to define mechanisms and pathways by which elevated CO2 impacts the antiviral immune response and host defence against influenza and SARS-CoV-2 in immune and epithelial cells. |
16:45-17:00 |
Discussion
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Chair
Professor Elizabete Carmo-Silva, Lancaster University, UK
Professor Elizabete Carmo-Silva, Lancaster University, UK
Elizabete is an expert on the regulation of carbon assimilation by Rubisco in crop plants, especially wheat and cowpea. She leads a research team that aims to understand and improve the efficiency of photosynthesis to optimise the sustainability and climate resilience of crop production. She received her undergraduate degree in applied plant biology at the University of Lisbon, where she went on to earn her PhD researching photosynthesis and photorespiration in C4 grasses. She specialised on the regulation of Rubisco by its molecular chaperone Rubisco activase as a postdoctoral researcher with the USDA-ARS, then started exploring this knowledge for crop improvement as a research scientist at Rothamsted Research. She moved to Lancaster University in 2015 to start a research group that focuses on Rubisco regulation in crops.
09:00-09:30 |
Carbon dioxide and immunometabolism
CO2 is produced during aerobic respiration. Normally, levels of CO2 in the blood are tightly regulated but pCO2 can rise (hypercapnia, pCO2>45mmHg) in patients with lung diseases e.g. COPD. Hypercapnia is a risk factor in COPD but may be of benefit in the context of destructive inflammation through suppression of pro-inflammatory signalling. Recently, we used an RNA-seq approach to determine the transcriptomic response of monocytes to hypercapnia (10% CO2, 4hrs) under pH -buffered conditions. We identified a cluster of 254 genes to be CO2 responsive under basal conditions and in the presence of a pro-inflammatory stimulus (LPS). Interestingly, genes encoding for mitochondrial proteins were highly represented in this cluster and nearly all mitochondrial encoded genes e.g. MT-CO1, MT-ND4 were enhanced under conditions of buffered hypercapnia. Mitochondrial DNA content was not enhanced, but acylcarnitine species and genes associated with fatty acid metabolism e.g. ACADSs were increased in hypercapnia. Primary IL-4 polarised macrophages exposed to buffered hypercapnia also increased expression of genes associated with fatty acid metabolism eg CPT1a and reduced expression of genes associated with glycolysis e.g. ALDOA and inflammation TNF. Taken together these data suggest that buffered hypercapnia is a robust metabolic stimulus that influences the inflammatory status of immune cells. Current work is directed towards dissecting the contribution of hypercapnia to immunometabolism in immune cells using integrated analysis of RNA-seq, LC-MS metabolomics as well as GC-MS stable isotope tracing data. These studies are important for understanding immune dysregulation in patients experiencing hypercapnia. Dr Eoin Cummins, University College Dublin, Ireland
Dr Eoin Cummins, University College Dublin, IrelandDr Cummins holds a BSc in Pharmacology and a PhD in molecular medicine. He is currently an Associate Professor in Physiology in the School of Medicine, University College Dublin. The Cummins lab focuses on the role of physiological gases eg Oxygen (O2) and carbon dioxide (CO2), in the context of health and disease. It is well known that areas of hypoxia (low O2) exist in regions of altered metabolic activity, ischemia, inflammation and cancer. Similarly, in areas with depleted oxygen, cellular and tissue carbon dioxide levels can rise, resulting in hypercapnia. The concentrations of these physiological gases are known to impact on cellular signaling and modify proliferative, healing and immune/ inflammatory responses. Current work in the Cummins lab is focused on understanding the contribution of carbon dioxide to metabolic signalling in immune cells and skeletal muscle. |
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09:30-09:45 |
Discussion
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09:45-10:15 |
The pyrenoid: a liquid-liquid phase separated CO2 fixing organelle
Approximately one-third of global carbon-fixation occurs in an overlooked algal organelle called the pyrenoid. The pyrenoid contains the CO2-fixing enzyme Rubisco and enhances carbon-fixation by supplying Rubisco with a high concentration of CO2. Recently we have gained novel insights into the molecular structure and biogenesis of this ecologically fundamental organelle by determining the spatial organization of pyrenoid proteins and showing that the pyrenoid is a liquid-liquid phase separated system. To expand our knowledge outside of a model alga we are now systematically characterizing pyrenoids across the eukaryotic tree of life including green algae, red algae, diatoms and macroalgae. Our data is providing insights into the convergent evolution of CO2-fixing biomolecular condensates and guiding the engineering of a pyrenoid into higher plants with a goal to enhance crop carbon fixation efficiency. Professor Luke Mackinder, University of York, UK
Professor Luke Mackinder, University of York, UKLuke is a UKRI Future Leader Fellow and a 2018 SEB Presidents Medallist for Cell Biology. His lab is applying high-throughput, systems and synthetic biology in diverse algae to rapidly dissect, predict and build CO2 fixing pathways. This data is being used to generate a blueprint for the engineering of efficient CO2 uptake systems in plants, with the goal of improving photosynthesis and ultimately crop yields and biological based carbon capture systems. Luke did a Marie Curie Funded PhD at the GEOMAR-Helmholtz Centre for Ocean Research Kiel, Germany and the Marine Biological Association of the UK. Followed by a 4-year postdoc at the Carnegie Institute for Plant Sciences, Stanford, before starting his own group at York in 2016. The Mackinder Lab is currently funded by the BBSRC, a BBSRC/NSF-Bio partnership award, EPSRC and the Bill and Melinda Gates Foundation. |
10:15-10:30 |
Discussion
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10:30-11:00 |
Break
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11:00-11:30 |
Protein carbamates as a biochemical mechanism of CO2 sensing
Carbon dioxide (CO2) is a widespread biological gas that triggers adaptive responses within organisms from all domains of life. However, the basic biochemical mechanisms through which organisms’ sense and respond to CO2 are poorly understood. One direct way that CO2 can modulate biological systems is by direct modification of free amine groups within proteins, forming a carbamate (Prot-CO2). This modification can serve as a dynamic switch to alter the structure and chemical properties at these protein sites. However, Prot-CO2 is notoriously challenging to detect on proteins using traditional analytical methods. Therefore, this modification has only been well-characterized on a handful of proteins and its diverse roles in biology are largely unknown. Herein, we describe a robust chemical proteomic method to quantitatively detect Prot-CO2 sites in proteins. Using this method, we identify several high-confidence sites within different proteomes and explore the biochemical regulation of high-interest sites. This proof-of-concept work sets the stage for exploring the role of this dynamic modification as a biochemical regulator of CO2 sensing in diverse organisms. Dr Dustin King, Simon Fraser University, Canada
Dr Dustin King, Simon Fraser University, CanadaDr Dustin King completed his CIHR-funded PhD in 2016 in the lab of renowned structural biologist Professor Natalie Strynadka at University of British Columbia, studying the biochemical basis of antibiotic resistance mechanisms and earning the Governor General's Gold Medal for the top PhD thesis. He then conducted postdoctoral research at SFU in Professor David Vocadlo’s lab, where he pioneered methods to study labile post-translational modifications. His work, supported by CIHR and MSFHR/CLEAR awards, included developing a method to identify CO₂-mediated carboxylation sites in proteins, enhancing understanding of CO₂-sensing mechanisms. In July 2022, he became an assistant professor in Simon Fraser University's MBB department, focusing on how cells respond to reactive metabolites. These metabolites form unique covalent bonds with protein residues, acting as chemical switches to regulate protein function. His research group develops innovative chemical proteomics methods to uncover these sites and characterise their biochemical and cellular mechanisms. |
11:30-11:45 |
Discussion
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11:45-12:15 |
Improving the Calvin-Benson-Bassham cycle the primary pathway for atmospheric CO2 uptake
Over the last 10 years a number of studies have provided evidence demonstrating that improving photosynthesis can result in improved yield. This talk will focus on improvements in the RuBP regeneration phase of the Calvin-Benson-Bassham cycle and also electron transport. I will summarise some of the results of successful studies using genetic engineering of steps in the photosynthetic process that led to increases in yield. These results provide clear evidence for the potential of increased photosynthesis to contribute to improving our crop plants. Professor Christine Raines, University of Essex, UK
Professor Christine Raines, University of Essex, UKChristine Raines graduated with a BSc (Hons) Agricultural Botany in 1982 and a PhD in Photosynthetic electron transport graduating in1986 form Glasgow University. Christine’s post-doctoral research started in late 1985 at the Institute of Plant Science Research, Cambridge, working on the molecular biology of C3 cycle. In 1988 Christine was appointed to a faculty position at the University of Essex being promoted to Professor in 2004. Christine was Head of the School of Life Sciences at Essex (2011-2017), Pro-Vice Chancellor Research (2017-2021) for the University of Essex and she held a number of external roles; Editor in Chief, Journal of Experimental Botany (2011- ), Chair of Plant Section, Society of Experimental Biology (2009- ) and SEB President (2017-2019). Christine’s research interests are in plant molecular physiology analysis of gene expression and production and analysis of transgenic plants. Currently Christine leads a research group focussed on improving photosynthesis by re-engineering the CO2 assimilatory pathway (the Calvin Benson cycle) and electron transport. |
12:15-12:30 |
Discussion
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Chair
Professor Martin Cann, Durham University, UK
Professor Martin Cann, Durham University, UK
Professor Cann’s core interests are in molecular mechanisms for inorganic carbon sensing. He has been part of teams that have made several foundational discoveries in this field. These include the discovery of the mammalian soluble adenylyl cyclase and its inorganic carbon regulation. This finding represented the first observation of a signalling molecule binding and responding to environmental inorganic carbon. He also contributed the finding that signalling molecules can be directly responsive to carbon dioxide, the molecular basis of carbon dioxide-regulated anion transport, the contribution of carbon dioxide to light-harvesting regulation in cyanobacteria, and new technology for discovering carbon dioxide-mediated post-translational modifications.
14:00-14:15 |
Discussion
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14:15-14:45 |
Acclimation of photosynthetic temperature in response to elevated CO2 and growth temperature in wheat
To assess the impact of climate change on wheat yield, it is important to reliably predict its photosynthetic acclimation to a combination of [CO2] and temperature changes. This study aimed to assess which photosynthetic parameters were most influenced by elevated [CO2] and growth temperature. To unravel acclimation of photosynthetic temperature response (An-T) and whether its parameters were dependent on growth [CO2], growth temperature or leaf rank, plants were grown under a range of temperatures (18 to 37 °C), two [CO2] (400 and 800 µbar) and assessed at two leaf ranks (leaf 4 and 6). Photosynthetic parameters most influenced by acclimation changes in An-T response and optimum temperature (Topt) were the activation energies of maximum Rubisco carboxylation (EVcmax) and of triose phosphate utilization (ETp), which increased 1.157 and 1.859 kJ mol-1, respectively, per °C increase in growth temperature. Changes depended on the most recently experienced growth temperature, regardless of [CO2] or growth temperatures during earlier growth. Under increasing [CO2] levels and growth temperature, as predicted in future climates, photosynthetic acclimation will be controlled by growth temperature and at higher [CO2] limitation of An set by triose phosphate utilization may occur more often in wheat. Dr Steven M Driever, Wageningen University, The Netherlands
Dr Steven M Driever, Wageningen University, The NetherlandsSteven Driever is an Assistant Professor in Crop Physiology at the Centre for Crop Systems Analysis at Wageningen University, the Netherlands. He obtained an MSc in Biology from Wageningen University and a PhD in Plant Physiology from the University of Essex, UK, where he specialised in photosynthesis. He held several post-doctoral positions at the University of Essex, Wageningen University and the University of Illinois, before he was appointed as an Assistant Professor at Wageningen University in 2019, with tenure from 2023. He has initiated a new joint photosynthesis laboratory where he has developed a range of new methods. In his group, experimentation and modelling are combined, to understand how photosynthesis interacts with its environment, from the chloroplast to the canopy level. |
14:45-15:00 |
Discussion
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15:00-15:30 |
Break
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15:30-16:00 |
Effects of hypercapnia stress on airway and pulmonary vascular structure
Carbon dioxide (CO2), a primary product of oxidative metabolism, can be sensed by eukaryotic cells eliciting specific responses via specific signalling pathways. In humans, hypercapnia - defined as the elevation of CO2 in the bloodstream and tissues - occurs in severe lung diseases. Hypercapnia is known to be associated with adverse outcomes in patients with chronic obstructive pulmonary disease (COPD). COPD is a progressive pulmonary disorder caused by structural remodelling of small peripheral airways which affects airway resistance and hyperreactivity. Dr Shigemura’s group has reported that elevated CO2 acts as a signalling molecule that promotes airway hyperreactivity and constriction, and that hypercapnic patients had higher airway resistance in COPD. In recent work, the group found that high CO2 induces hypertrophic changes in lung smooth muscle cells and activates fibroblasts to produce extracellular matrix proteins, which results in structural remodelling of the lung with smooth muscle hypertrophy and extracellular matrix deposition around the peri-bronchial and peri-vascular area. These data suggest that CO2 accumulates in the shared interstitial space between the airways and the pulmonary vasculature (broncho-vascular bundle) during respiratory failure. Dr Shigemura will provide new evidence that hypercapnia causes adverse structural remodelling of the lung and may drive COPD pathogenesis and progression. Dr Masahiko Shigemura, Northwestern University, USA
Dr Masahiko Shigemura, Northwestern University, USAMasahiko Shigemura is a Research Assistant Professor of Surgery at Northwestern University (USA). He obtained his PhD in Medicine from Hokkaido University (Japan) and subsequently carried out post-doctoral research in the laboratory of Dr Jacob I Sznajder at Northwestern University. His primary research focuses on airway smooth muscle contractility during hypercapnia, a topic with potential clinical relevance for patients with obstructive lung diseases such as chronic obstructive pulmonary disease (COPD). As a Research Assistant Professor, he has been expanding his scientific expertise and conducting research to address airway pathobiology in the context of hypercapnia and COPD. |
16:00-16:15 |
Discussion
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16:15-16:45 |
Encapsulation and regulation of carboxysomal carbonic anhydrases (online talk)
Rubisco is responsible for the majority of inorganic carbon assimilation on Earth. To ensure efficient CO2-fixation Cyanobacteria and many autotrophic Proteobacteria concentrate CO2 in proteinaceous organelles called carboxysomes. This organelle encapsulates key enzymes for CO2 fixation, Rubisco and carbonic anhydrase, and are the centrepiece of the bacterial CO2 concentrating mechanism (CCM). In the CCM, actively accumulated bicarbonate diffuses into the carboxysome and is converted to CO2 by carbonic anhydrase. This produces a high CO2 concentration near Rubisco ensuring efficient carboxylation. It remains unknown exactly how this 250+ megadalton protein complex assembles with high fidelity inside cells. The self-assembly of the α-carboxysome is orchestrated by the intrinsically disordered scaffolding protein, CsoS2, which interacts with both Rubisco and carboxysomal shell proteins. But, it’s been unknown how CsoSCA, the carbonic anhydrase, is incorporated into the α-carboxysome. Here, I will discuss our recent work on the structural basis of carbonic anhydrase encapsulation into α-carboxysomes from Halothiobacillus neapolitanus. We find that CsoSCA interacts directly with Rubisco via an intrinsically disordered N-terminal domain. A sub 2 Å single-particle cryo-EM structure of Rubisco in complex with this peptide reveals that CsoSCA binding is predominantly mediated by a network of hydrogen bonds. CsoSCA's binding site overlaps with that of CsoS2 but the two proteins utilise substantially different motifs and modes of binding, revealing a plasticity of the Rubisco binding site. Our results update the current model for carboxysome biogenesis and inform strategies for engineering CO2 concentration mechanisms into crops and industrially relevant microorganisms for improved growth and yields. Dr Cecilia Blikstad, Uppsala University, Sweden
Dr Cecilia Blikstad, Uppsala University, SwedenCecilia (Cissi) obtained her PhD in Biochemistry from Uppsala University working on mechanistic enzymology and directed evolution of alcohol dehydrogenases. She thereafter moved to University of California Berkeley for a postdoc. Here she studied biochemical aspects of bacterial carbon fixation in David Savage lab. She specifically focused on the carboxysome, a specialised organelle which encapsulates the key enzymes for CO2-fixation, Rubisco and carbonic anhydrase. In 2021 she returned back to Uppsala to start her independent research group and continue the research on the cyanobacterial CO2 concentration mechanism. |
16:45-17:00 |
Discussion
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