Dicty News
Electronic Edition
Volume 22, number 7
March 26, 2004

Please submit abstracts of your papers as soon as they have been
accepted for publication by sending them to dicty@northwestern.edu
or by using the form at
http://dictybase.org/db/cgi-bin/dictyBase/abstract_submit.

Back issues of Dicty-News, the Dicty Reference database and other 
useful information is available at dictyBase - http://dictybase.org.



=============
  Abstracts
=============

  

The identification of Dictyostelium phosphoproteins altered in response to 
the activation of RasG

David M. Secko(1), Robert H. Insall(2), George B. Spiegelman(1) and 
Gerry Weeks(1)

>From the (1)Department of Microbiology and Immunology, University of 
British Columbia, 300-6174 University Blvd., Vancouver, British Columbia, 
V6T 1Z3, Canada and the (2)School of Biosciences, University of Birmingham, 
Birmingham, B15 2TT, U.K.

Proteomics, in press

Dictyostelium RasG has been implicated in the regulation of a variety of 
cellular processes, including the initiation of development, cell movement, 
and cytokinesis, but the molecular components of the signaling pathways 
involved are largely unknown. We used a tetracycline-regulated protein 
expression system to study the effect of activated RasG, RasG(G12T), 
expression on the phosphorylation state of Dictyostelium proteins. Over 70 
vegetative phosphoprotein components were resolved by 2D immunoblot analysis 
and of these 16 phosphothreonine and 3 phosphotyrosine protein components 
were found to reproducibly change upon RasG(G12T) expression. Thirteen of 
these were recovered from 2D gels and identified by mass spectrometry of 
in-gel tryptic digestions. The proteins identified include the signaling 
proteins RasGEF-R and PKB, the adhesion protein DdCAD-1, the cytoskeletal 
protein actin, the mitochondrial division protein FtsZA, and proteins 
involved in translation and metabolism. In addition to the direct 
demonstration of the phosphorylation of putative downstream targets of
 RasG activation, these findings reveal previously undetected 
phosphorylation of several proteins. 

Submitted by: David Secko [dmsecko@interchange.ubc.ca]


===============================================================================
[End Dicty News, volume 22, number 7]