Semisynthesis of caged phosphoproteins: Myosin regulatory light chain as a chemical tool in studies of cell migration

ORGN 133

Brenda N. Goguen, bgoguen@mit.edu, Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 and Barbara Imperiali, imper@mit.edu, Department of Chemistry and Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139.
Caged phosphoproteins are powerful chemical tools that provide temporal and spatial control for examining complex signaling pathways within biological systems in a UV-inducible manner. The ATPase activity of myosin II, a motor protein essential for cell motility, is regulated by the phosphorylation state of Ser19 and Thr18 of the associated 20 kDa myosin regulatory light chain (mRLC). To create a tool for studying the role of myosin II in cell migration, the full length mRLC was synthesized by native chemical ligation to introduce 1-(2-nitrophenyl)ethyl caged phosphorylated serine and threonine at positions 19 and/or 18, respectively in the 171-residue protein. Following the in vitro exchange of the semisynthetic mutants into native myosin II, activity of the caged and uncaged proteins was characterized with actin-activated ATPase assays. The proteins are promising for cellular studies because active myosin can be generated upon photolysis, allowing effects of phosphorylation-mediated myosin regulation to be investigated.

 

Total Synthesis, Materials, Devices and Switches, Molecular Recognition and Self-Assembly, Biologically-Related Molecules and Processes
8:00 PM-10:00 PM, Sunday, August 19, 2007 BCEC -- Exhibit Hall - B2, Poster

Sci-Mix
8:00 PM-10:00 PM, Monday, August 20, 2007 BCEC -- Exhibit Hall - B2, Sci-Mix

Division of Organic Chemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007