Richard A. Murphy, Ph.D.
|Address:||Molecular Physiology |
and Biological Physics
University of Virginia
PO Box 800736
Charlottesville, VA 22908-0736
Smooth muscles differ from skeletal muscles in havig the capacity to regulate their power output which is a function of crossbridge cycling rates. The kinetics of crossbridge cycling are determined by a covalent regulatory system. We are testing a hypothesis that Ca++-dependent crossbridge phosphorylation and dephosphorylation by myosin light chain kinase and phosphatase occur at rates comparable to crossbridge turnover and, in fact, determine the latter. This hypothesis has been mathematically modeled and specific predictions are being tested through biophysical and energetics approaches.
Murphy, R.A. (1994) What is special about smooth muscle? The significance of covalent crossbridge regulation. FASEB J. 8:311-318. [View Entrez Listing]
Wardle RL, Strauss JD, Rembold CM, Murphy RA. Heterologous desensitization of smooth muscle to K+ depolarization: retarded stimulus-[Ca2+]i coupling. Am J Physiol. 1997 Jun; 272(6 Pt 1): C1810-C1820. [View Entrez Listing]
Wingard CJ, Paul RJ, Murphy RA. Energetic cost of activation processes during contraction of swine arterial smooth muscle. J Physiol (Lond). 1997 May 15; 501( Pt 1): 213-223. [View Entrez Listing]
Drew JS, Murphy RA. Actin isoform expression, cellular heterogeneity, and contractile function in smooth muscle. Can J Physiol Pharmacol. 1997 Jul; 75(7): 869-877. [View Entrez Listing]