My laboratory is interested in the mechanisms that regulate contraction of smooth muscles. We use biophysical, structural, and kinetic techniques to study the structure and function of myosin and actin, the major contractile proteins. These studies are addressing the structural mechanisms that control the activity of myosin. Smooth muscle myosin is regulated by phosphorylation, resulting in large conformational changes. The inactive unphosphorylated state is self-inhibited by interaction of the myosin tail domain with the catalytic and regulatory domains. We are studying the structure of this inhibited state by photocross-linking, fluorescence quenching and polarization, electron paramagnetic resonance, phosphorescence anisotropy, mass spectrometry and crystallography. Self-inhibited myosin is in equilibrium with myosin filaments, which is the force-generating conformation.
We are interested in understanding the regulation of this equilibrium in the cell. Major approaches are measurements of contractile force in intact tissues, immunofluorescence microscopy of transiently-transfected cells, dynamic imaging of GFP- and other fluorescent constructs in live cells, mutagenesis, and fluorescence photo-bleaching recovery.
