A double point mutation in PCL-gamma1 (Y509A/F510A) enhances Y783 phosphorylation and inositol phospholipid-hydrolyzing activity upon EGF stimulation.
10.3858/emm.2010.42.3.023
- Author:
Sang Hee CHUNG
1
;
Sung Kuk KIM
;
Jung Kuk KIM
;
Yong Ryoul YANG
;
Pann Ghill SUH
;
Jong Soo CHANG
Author Information
1. Department of Life Science, College of Natural Science, Daejin University, Pocheon 487-711, Korea. jchang@daejin.ac.kr
- Publication Type:Original Article ; Research Support, Non-U.S. Gov't
- Keywords:
phosphatidylinositol 4,5-bisphosphate;
phospholipase Cgamma;
protein-tyrosine kinases;
src homology domains
- MeSH:
Amino Acid Substitution/drug effects/*genetics;
Animals;
COS Cells;
Cercopithecus aethiops;
Enzyme Activation/drug effects;
Epidermal Growth Factor/*pharmacology;
Hydrolysis/drug effects;
Mutant Proteins/metabolism;
Phosphatidylinositols/*metabolism;
Phospholipase C gamma/*genetics/metabolism;
Phosphorylation/drug effects;
Phosphotyrosine/*metabolism;
Point Mutation/*genetics;
Rats
- From:Experimental & Molecular Medicine
2010;42(3):216-222
- CountryRepublic of Korea
- Language:English
-
Abstract:
Growth factor stimulation induces Y783 phosphorylation of phosphoinositide-specific PLC-gamma1, and the subsequent activation of this enzyme in a cellular signaling cascade. Previously, we showed that a double point mutation, Y509A/F510A, of PLC-gamma1, abolished interactions with translational elongation factor 1-alpha. Here, we report that the Y509A/F510A mutant PLC-gamma1 displayed extremely high levels of Y783 phosphorylation and enhanced catalytic activity, compared to wild-type PLC-gamma1, upon treatment of COS7 cells with EGF. In quiescent COS7 cells, the Y509A/F510A mutant PLC-gamma1 exhibited a constitutive hydrolytic activity, whereas the wild-type counterpart displayed a basal level of activity. Upon treatment of COS7 cells with EGF, the Y783F mutation in Y509A/F510A PLC-gamma1 (Y509A/F510A/Y783F triple mutant) cells also led to an enhanced catalytic activity, whereas Y783F mutation alone displayed a basal level of activity. Our results collectively suggest that the Y509A/F510A mutant is more susceptible to receptor tyrosine kinase-induced Y783 phosphorylation than is wild-type PLC-gamma1, but no longer requires Y783 phosphorylation step for the Y509A/F510A mutant PLC-gamma1 activation in vivo.
