Translocation of Ki-ras p21 between membrane and cytoplasm by smg GDS.
We have previously shown that smg GDS forms a complex with Ki-ras 4B p21 and thereby stimulates its GDP/GTP exchange reaction. We have shown here that smg GDS inhibits the binding of Ki-ras 4B p21 to membranes and induces the dissociation of prebound Ki-ras 4B p21 from membranes. Moreover, we have found that cotransfection of the smg GDS and Ki-ras 4B p21 cDNAs into COS7 cells increases the ratio of the cytosolic form of ras p21 to the membrane-bound form and the ratio of the GTP-bound form of ras p21 to the GDP-bound form. These results indicate that smg GDS regulates not only the GDP/GTP exchange reaction of Ki-ras 4B p21 but also its translocation between membrane and cytoplasm.
Kawamura
M
M
Department of Biochemistry, Kobe University School of Medicine, Japan.
Kaibuchi
K
K
Kishi
K
K
Takai
Y
Y
D000818:Animals; D002451:Cell Compartmentation; D002474:Cell-Free System; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D003593:Cytoplasm / Q000378:metabolism; D004910:Erythrocyte Membrane / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000378:metabolism*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D066298:In Vitro Techniques; D008970:Molecular Weight; D016283:Proto-Oncogene Proteins p21(ras) / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D020668:rap GTP-Binding Proteins
D005656:Fungal Proteins; D011994:Recombinant Proteins; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate; D019204:GTP-Binding Proteins; D016283:Proto-Oncogene Proteins p21(ras); D020668:rap GTP-Binding Proteins