Alfred Wittinghofer: GTP-Binding Proteins as Molecular Switches

I. GTP-Binding Proteins as Molecular Switches
II. GTPase Reactions and Diseases

Part II: GTPase Reactions and Diseases

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Lecture Overview
When a growth factor binds to the plasma membrane of a quiescent cell, an intracellular signaling pathway is activated telling the cell to begin growing. A key molecule in this signaling pathway is the GTP-binding protein, or G-protein, Ras. Ras can act as an on-off switch telling the cell to grow or not. In its inactive form, Ras is bound to GDP while in its active form it is bound to GTP. This exchange of nucleotides is catalysed by guanine nucleotide-exchange-factors (GEFs). The return to the inactive state occurs through the GTPase reaction, which is accelerated by GTPase-activating proteins (GAPs). In Part 1 of his talk, Dr. Wittinghofer explains how solving the three-dimensional structure of Ras, and other G-proteins, allowed him to understand the conserved mechanism by which G-proteins can act as switches. The structure also identified domains unique to each G-protein that provide the specificity for downstream signals.  More >>

Speaker Bio
Dr. Wittinghofer received his PhD from the German Wool Research Institute and pursued postdoctoral work at the University of North Carolina where he studied protein modification. He then returned to Germany where he joined the Max-Planck Institute in Heidelberg and continued studies of the structure and function of proteins involved in protein biosynthesis such as EF-Tu. As a group leader, he started working on small G proteins such as Ras, Ran and Rap and taught at the University of Heidelberg. Wittinghofer then moved to the Max-Planck Institute of Molecular Physiology (MPI) in Dortmund where he was director of the Department of Structural Biology from 1993 through 2009. During this time, he taught Biochemistry at the University of Bochum nearby. He continues as an Emeritus Group Leader at the MPI where research in his lab focuses on structural, functional, and mechanistic investigation of GTP-binding proteins and their regulators. More >>

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