title: rap1 p21 regulates the interaction of ras p21 with RGL, a new effector protein of ras p21.
abstract: We have recently found that ralGDS family members (RGL and ralGDS) are putative effector proteins of ras p21. rap1 p21 is a small GTP-binding protein which has the same amino acid sequence as the effector loop of ras p21. We examined the effect of rap1 p21 on the interaction of ras p21 with RGL. The GTP-bound form of rap1 p21 interacted with RGL as well as did ras p21. rap1 p21 inhibited the interaction of ras p21 with RGL. RGL was phosphorylated by cyclic AMP-dependent protein kinase (protein kinase A). Phosphorylation of RGL did not affect its binding to ras p21 and rap1 p21 under the conditions that phosphorylation of Raf-1 reduced its affinity for ras p21. These results demonstrate that rap1 p21 but not protein kinase A regulates the interaction of ras p21 with RGL and suggest that rap1 p21 and protein kinase A may cooperate to distinguish the signal or ras p21 to RGL from that to Raf-1.
mesh_terms: D003001:Cloning, Molecular; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004926:Escherichia coli; D019204:GTP-Binding Proteins / Q000378:metabolism*; D011905:Genes, ras; D005982:Glutathione Transferase / Q000096:biosynthesis; D020662:Guanine Nucleotide Exchange Factors; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D006153:Guanosine Diphosphate / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D007700:Kinetics; D010766:Phosphorylation; D011485:Protein Binding; D017433:Protein Structure, Secondary; D016283:Proto-Oncogene Proteins p21(ras) / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000378:metabolism; D013379:Substrate Specificity; D014157:Transcription Factors / Q000378:metabolism*; D020726:ral Guanine Nucleotide Exchange Factor; D020668:rap GTP-Binding Proteins
chemical_list: D020662:Guanine Nucleotide Exchange Factors; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; C097104:Rgl1 protein, mouse; D014157:Transcription Factors; D020726:ral Guanine Nucleotide Exchange Factor; D006153:Guanosine Diphosphate; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate; D005982:Glutathione Transferase; D017868:Cyclic AMP-Dependent Protein Kinases; D019204:GTP-Binding Proteins; D016283:Proto-Oncogene Proteins p21(ras); D020668:rap GTP-Binding Proteins