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 Actin-based movements:
We study
how cells control
the assembly and disassembly of actin filaments during cellular
movements. We
have projects on the structure and function of actin, Arp2/3 complex,
activators
of Arp2/3 complex (such as the Wiskott-Aldrich syndrome protein, WASp),
profilin,
ADF/cofilin and capping protein.
Accomplishments
include the discovery and characterization of Arp2/3 complex, an
assembly of two actin-related proteins and seven novel subunits. We
determined the crystal structure of Arp2/3 complex and developed a
method to visualize the growth of actin filaments in real time by
fluorescence microscopy. These breakthroughs opened the way to
understand how Arp2/3 complex forms branches on the sides of actin
filaments at the leading edge of motile cells and actin patches used by
fungi for endocytosis. We have also helped to establish the molecular
pathway of cytokinesis in fission yeast.
Ribbon
diagram of the 2.0 Å crystal structure of the bovine Arp2/3 complex.
Ref: Robinson*, R.C., Turbedsky*, K., Kaiser, D.A., Higgs, H.N.,
Marchand, J.-B., Choe, S. and Pollard, T.D. (2001) Crystal structure of
Arp2/3 complex. Science 294:1679-1684. * co-first authors.
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 Molecular
mechanism of cytokinesis:
Over the past
decade our lab adopted fission yeast
as our model system for studying cytokinesis. We used quantitative
fluorescence microscopy of fluorescent fusion
proteins to establish the temporal and spatial pathway of contractile
ring assembly and constriction and to measure the global and local
concentrations of 30 proteins
that participate in the process. We characterized the biochemical
properties of
several of the
cytokinesis proteins, including myosin-II, formins, profilin, capping
protein
and cofilin. We combined this information in mathematical models that
allow us to
test our hypotheses about the cytokinesis pathway and to suggest
fruitful opportunities
for new research.
Stereo
pair of fluorescence micrographs showing the localization of
GFP-myosin-I in S. pombe. Ref: Lee, W.-L., Bezanilla, M. and Pollard,
T.D. (2000) Fission yeast myosin-I, Myo1p, stimulates actin assembly by
Arp2/3 complex and shares functions with WASp. J. Cell Biol.
151:789-800.
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Lab News:
See the new paper in Cell where Tom Pollard explains why scientists should advocate for governmental support of basic research. [pdf]
Julien Berro wins the 2012 Yale MCDB Retreat Poster Prize for post docs!
Last Updated: May 10, 2013 (203-432-3194)
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