Laboratory of Molecular Physiology (LMP)
James R Sellers, PhD, Principal Investigator
Our research focuses on the structure, function and regulation
of myosins, a class of actin-dependent
motor proteins. There are currently at least eighteen classes of
myosin that have been identified by phylogenetic analysis of the
motor domains. Many of the myosin classes are represented by multiple
genes within a given organism. We are particularly interested in
how different classes of myosins have adapted their structure and
kinetics to allow them to participate in such diverse tasks inside
cells as contraction of muscle, contraction of cytokinetic rings,
cell adhesion, cell motility, phagocytosis, endocytosis, and trafficking
of vesicles, mRNA and other cargo in cells. Our lab studies myosins
from classes II, III, V, VII, IX, XV and XVIII. We use a variety
of approaches ranging from transient state kinetic analysis to cell
biological studies of the proteins in cells. Optical trapping and
total internal reflection fluorescence (TIRF) microscopy are used
to study the mechanics of single myosin molecules. We use the baculovirus/SF9
system to express many myosins that are difficult or impossible
to purify or to make mutants of these myosins to test structure/function
hypotheses.
We are also interested in the role of myosins in cells and are
using live cell microscopy of cells expressing GFP-tagged versions
of different myosins to study their localization and dynamics. Drosophila
contains many of the same myosins as found in mammalian genomes.
We are using this organism as a model system to study myosin function.
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