CSM News
Electronic Edition
Volume 1, number 12
August 7, 1993

Please submit abstracts of your papers as soon as they have been
accepted for publication by sending them to CSM-News@worms.cmsbio.nwu.edu.

Back issues of CSM-News, the CSM Reference database and other useful
information is available by anonymous ftp from worms.cmsbio.nwu.edu
[129.105.233.50].

=====================
Richard Gomer writes:
=====================

Help!  Dave Knecht and I need the recipe for Sorenson's phosphate
buffer.  Could someone please send the recipe to richard@rice.edu?
Many Thanks,

Richard Gomer


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Abstracts
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Mutagenesis of Dictyostelium Myosin Heavy Chain Phosphorylation
Sites: Direct Evidence that These Sites Regulate Myosin Filament
Assembly and Localization In Vivo.

Thomas T. Egelhoff, Randall J. Lee, and James A. Spudich.  

Department of Physiology and Biophysics, Case Western Reserve
School of Medicine, Cleveland, OH; and Department of 
Biochemistry, Stanford University School of Medicine, Stanford
CA.

Cell, in press.

Abstract

   Three threonine residues in the tail of Dictyostelium
myosin II heavy chain have been implicated previously in 
control of myosin filament formation.  Here we report the in 
vitro and in vivo consequences of converting these sites to 
alanine residues, which eliminates phosphorylation at these 
positions, or to aspartate residues, which mimics the negative
charge state of the phosphorylated molecule.  Alanine 
substitution allows in vitro assembly and in vivo contractile
activity, although this myosin shows substantial overassembly
in vivo.  Aspartate substitution eliminates filament assembly
in vitro and renders the myosin unable to drive any tested 
contractile event in vivo.  These results demonstrate that
heavy chain phosphorylation plays a key modulatory role in 
controlling myosin function in vivo.

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[END CSM-News, volume 1, number 12]