Src homology 2 and 3 regions of p120 kDa rasGTPase activating protein induces morphological alteration of rat 3Y1 fibroblast

Abstract

pl20 kDa rasGTPase activating protein (GAP), as a negative regulator of pH™5, contains src homology (SH) 2 and 3 regions just upstream of catalytic domain, which has no GTPase activity but it stimulates GTPase activity of normal c-ras gene product To investigate the differential role of non-catalytic regulatory domain of GAP in cell growth control，we constructed a truncated gene encoding 164-449 amino acids of rat GAP which correspond to SH2/SH3 re없on alone and expressed in rat fibroblast using stable mammalian expression vector. Expression of only SH2/SH3 re建on of GAP in 3Y1 cells resulted in a morphological alterations. Furthermore, this SH2/SH3 re建on expressing clones showed increased phosphotyrosine levels of pl90 and p62 when those cells were incubated in orthovanadate, a protein phosphatase inhibitor. These results suggest that src homology regions of pl20 kDa GAP have a unique biological activity in cellular signaling.