title: The Ras/p120 GTPase-activating protein (GAP) interaction is regulated by the p120 GAP pleckstrin homology domain.
abstract: Pleckstrin homology domains are structurally conserved functional domains that can undergo both protein/protein and protein/lipid interactions. Pleckstrin homology domains can mediate inter- and intra-molecular binding events to regulate enzyme activity. They occur in numerous proteins including many that interact with Ras superfamily members, such as p120 GAP. The pleckstrin homology domain of p120 GAP is located in the NH(2)-terminal, noncatalytic region of p120 GAP. Overexpression of the noncatalytic domains of p120 GAP may modulate Ras signal transduction pathways. Here, we demonstrate that expression of the isolated pleckstrin homology domain of p120 GAP specifically inhibits Ras-mediated signaling and transformation but not normal cellular growth. Furthermore, we show that the pleckstrin homology domain binds the catalytic domain of p120 GAP and interferes with the Ras/GAP interaction. Thus, we suggest that the pleckstrin homology domain of p120 GAP may specifically regulate the interaction of Ras with p120 GAP via competitive intra-molecular binding.
authors.affiliation: Department of Cell and Cancer Biology, NCI, National Institutes of Health, Rockville, Maryland 20850-3300, USA.
authors.forename: J K
authors.initials: JK
authors.lastname: Drugan
authors.forename: K
authors.initials: K
authors.lastname: Rogers-Graham
authors.forename: T
authors.initials: T
authors.lastname: Gilmer
authors.forename: S
authors.initials: S
authors.lastname: Campbell
authors.forename: G J
authors.initials: GJ
authors.lastname: Clark
mesh_terms: D016475:3T3 Cells; D000818:Animals; D001798:Blood Proteins / Q000737:chemistry; D019556:COS Cells; D002455:Cell Division; D018076:DNA, Complementary / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases; D050356:Lipid Metabolism; D048670:MAP Kinase Kinase 4; D020935:MAP Kinase Signaling System; D051379:Mice; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D010750:Phosphoproteins / Q000737:chemistry; D016133:Polymerase Chain Reaction; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D019908:Proto-Oncogene Proteins c-raf / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction; D013997:Time Factors; D014162:Transfection; D014170:Transformation, Genetic; D020729:p120 GTPase Activating Protein / Q000378:metabolism*; D018631:ras Proteins / Q000378:metabolism
chemical_list: D001798:Blood Proteins; D018076:DNA, Complementary; D010750:Phosphoproteins; D011994:Recombinant Proteins; D020729:p120 GTPase Activating Protein; C039077:platelet protein P47; D005982:Glutathione Transferase; D019908:Proto-Oncogene Proteins c-raf; D048031:JNK Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases; D018631:ras Proteins