Biography

Thomas D. Pollard graduated from Pomona College in 1964 with honors in Chemistry and Zoology. At Harvard Medical School he began a life time of research on the molecular basis of cellular movements. He and his colleagues have discovered and characterized a number of protein molecules that produce the forces for cells to move from place to place. They combined microscopy, biochemistry, biophysics, molecular biology and genetics to provide the evidence to formulate a detailed molecular explanation for how assembly of actin filaments produces cellular movements. His group is now using the same approaches to learn how cells divide in two at the end of the cell cycle.

In addition to research and teaching, Pollard served as Director of the Department of Cell Biology and Anatomy at Johns Hopkins Medical School for 19 years and as President of the Salk Institute for Biological Studies in La Jolla, California for 4 years. At Yale University he is Sterling Professor and Chair of Molecular Cellular and Developmental Biology. On the national level Pollard has served as president of two major scientific societies and has had leadership positions at the National Academy of Sciences.

Pollard's honors include the Gaidner International Award, E.B. Wilson Award from the American Society for Cell Biology, Rosensteil Award for Basic Biomedical Research from Brandeis University (with James Spudich) and the Ricketts Award from University of Chicago. His is a member of the American Academy of Arts and Sciences, the National Academy of Sciences and the Institute of Medicine.
 

Thomas D. Pollard, Ph.D.

Sterling Professor and Chair of Molecular,
Cellular & Developmental Biology
Yale University

www.cellbiology.yale.edu/cellbio/html/faculty/t_pollard.shtml www.yale.edu/pollard_lab/

Molecular Mechanisms of
Cellular Motility and Cytokinesis

Abstract:
We use biophysical analysis of purified proteins and observations of live cells to study cellular motility and cytokinesis. Arp2/3 complex nucleates branched actin filaments that push forward the leading edge of motile eukaryotic cells and cortical actin patches in fungi. Cooperative binding of WASp/Scar nucleation promoting factors, the first actin subunit in the daughter filament and mother filaments activate Arp2/3 complex to form branches. Some of these events can be visualized and quantitated in real time in fission yeast actin patches.

Fission yeast assemble a contractile ring for cytokinesis in a strict temporal and spatial order starting with about 75 small nodes of protein around the equator of the cell. Nodes assemble from ~20 anillin-like proteins, followed by 20 myosin-IIs, 20 IQ-GAPs, 2 formin Cdc12p dimers, and 20 Cdc15p PCH proteins, all independent of actin. The formins initiate polymerization of an unbranched actin filament and remain bound to its elongating barbed end for hundreds of seconds. Myosin-II pulls the nodes together into a compact ring. About 25 minutes later the UCS protein Rng3p allows myosin-II to constrict the ring, which disassembles as it constricts.