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Faculty
Dennis E. Koppel
Professor of Molecular, Microbial & Structural Biology
Our long term goals have been the correlation of surface membrane
macromolecular diffusional dynamics with cell (or membrane) function,
and the development of new approaches for evaluating diffusional
dynamics parameters for both lipids and proteins. Fluorescence
redistribution after photobleaching (FRAP), total internal reflection
FRAP (TIR-FRAP), fluorescence correlation spectroscopy (FCS), single
particle tracking (SPT), and confocal microscopy methods have been used
to establish macromolecular distribution and mobility characteristics.
These approaches were utilized to examine the diffusional behavior of
such seemingly diverse systems as membrane proteins on sperm cell
surfaces, thy-1 antigen on the surface of 3T3 fibroblasts, the
distribution and diffusional dynamics of EGF receptor and the ICAM-1
adhesion molecule on fibroblast and endothelial cell surfaces. Work has
concentrated on two specific areas: the factors that restrict and
control the rate of lateral diffusion of integral membrane proteins and
lipids; and the mechanisms that produce and maintain specialized domains
on the surfaces of differentiated cells. It is expected that such
studies will continue to give new insight into the structural
organization of the cell, and the dynamics of intracellular
interactions.
Selected Publications:
Cowan, AE. Olivastro E. M. Koppel DE. Loshon CA. Setlow B. Setlow P.
Lipids in the inner membrane of dormant spores of Bacillus species are
largely immobile Proceedings of the National Academy of Sciences of
the United States of America. 2004 In press.
Cowan AE. Koppel DE. Setlow B. Setlow P. A soluble protein is
immobile in dormant spores of Bacillus subtilis but is mobile in
germinated spores: implications for spore dormancy. [Journal Article]
Proceedings of the National Academy of Sciences of the United States of
America. 100(7):4209-14, 2003.
Cowan AE. Koppel DE. Vargas LA. Hunnicutt GR. Guinea pig fertilin
exhibits restricted lateral mobility in epididymal sperm and becomes
freely diffusing during capacitation. Developmental Biology.
236(2):502-9, 2001. |
