Professor Alan Hall FRS
Alan Hall was distinguished for his contributions to the understanding of the Rho family of ras-realted GTPases - Rho, Rac and Cdc42. He discovered the GTPase-activating protein for Rho (Rho GAP) and showed that it was related to the product of the bcr oncogene that is rearranged in human leukaemias displaying the Philadelphia chromosome. He showed that the Bcr protein has GAP activity for Rac and Cdc42. In collaboration with Tony Segal, he showed that Rac is an essential regulatory component of NADPH oxidase, the first function identified for a Rho family member. His most important discovery was that the Rho proteins are involved in signalling from growth factor receptors to the actin cytoskeleton: Rho is involved in the assembly of focal adhesions and actin stress fibers, Rac in the formation of lamellipodia and membrane ruffles, and Cdc42 in the formation of filopodia. These findings promise to revolutionise our understanding of how extracellular signals regulate cell motility.
Professor Alan Hall FRS died on 3 May 2015.