Telephone: (301) 496-1616

E-mail: korne@nhlbi.nih.gov

Office: Building 50, Room 2517

Mailing Address:
National Heart, Lung, and Blood Institute
50 South Drive, MSC 8017 

Bethesda, Maryland 20892-8017 

Role of myosin II in cytokinesis and development in Dictyostelium

Structural studies of Ancanthamoeba myosin I and myosin II

Correlation of myosin structure and function

Members of the very large myosin superfamily have essential roles in cellular processes of all eukaryotic cells.  Myosins are actin-based motors with actin-activated ATPase activity that is coupled to mechanical and structural events involving the actin filaments.  The actin-dependent ATPase activity of different myosins in nonmuscle cell is regulated by phosphorylation of either the heavy chain, the light chain, or both.  We are particularly interested in the mechanisms by which light and heavy chain phosphorylation regulate the activity of Class I  and Class II myosins through cooperative interactions between the head and tail domains of the heavy chains of these myosins.  The kinase that phosphorylates the heavy chain of ameboid Class I myosins is a member of the PAK family.  We are investigating the mechanism of this regulation and the role of Paks in the reorganization of the cytoskeleton of mammalian cells in culture.  By extensive use of mutated myosins and chimeras of head and tail regions of different Class I and Class II myosins, we are correlating the biochemical and biophysical properties of the pure proteins in vitro to their ability to support specific cellular activities.  Currently, for example, we are investigating the requirements fro a Class II myosin to support cytokinesis and differentiation of Dictyostelium discoideum, the structural basis of the regulation of Acanthamoebae myosin II activity by phosphorylation of sites at the tip of the coiled-coil rod, and the domain structure of Class I myosin.