Colorado State University NSF-REU Program in
Chemistry
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B. George Barisas
For
more information, visit our group webpage…
The
particular focus of our research group is the motions and distribution of
specific molecules on living cell surfaces and we have developed on the world's
broadest collections of instrumental facilities for such measurements. Changes
in these motions as various cell signaling events occur suggest functional
interactions between the protein of interest and other membrane species.
Despite the biological motivation for these studies, many of our people have little
or no prior training in biology but come from chemistry backgrounds.
Undergraduates typically select an independent project of their own but work
with the assistance of a more senior group member.
Work
in our group is organized in two ways: 1) by the types of techniques being
developed and 2) by the biological problem areas to which they are applied. The
types of techniques we are currently developing are 1) single-particle tracking
microscopy to measure diffusion of individual protein molecules on cell
surfaces, 2) continuous fluorescence depletion anisotropy to measure rotation
of specific cell surface proteins, 3) microscopic fluorescence lifetime
apparatus to evaluate fluorescence energy transfer efficiency inside cells and
4) high intensity spot photobleaching recovery to obtain the maximum diffusion
information from small numbers of fluorophores on a cell surface. Each of these
methods involves developing both physical instruments and data analysis
procedures. Almost everyone in the laboratory also routinely uses existing
techniques of fluorescence photobleaching recovery, time-resolved
phosphorescence anisotropy and photobleaching energy transfer in their work.
The
biological systems we currently study are 1) major histocompatibility complex
(MHC) class II antigens involved in antigen presentation by B cells to T cells,
2) the mast cell MAFA protein which inhibits cell degranulation triggered by
these cells' IgE receptors (i.e. allergic responses) and 3) the luteinizing
hormone receptor on various cells involved in mammalian reproduction. All these
projects involve the study of cell lines expressing structural mutants of the
proteins of interest. They also involve prominent collaborators from other
institutions.
Supported by
NSF-REU
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