Purification and characterization of G proteins from human brain: modification of GTPase activity upon phosphorylation
| Autor: | Michel Maitre, Claude Sauvage, J.F. Rumigny |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
GTPase-activating protein
G protein Clinical Biochemistry Cross Reactions Biology Mitogen-activated protein kinase kinase Guanosine Diphosphate GTP Phosphohydrolases MAP2K7 Proto-Oncogene Proteins p21(ras) GTP-Binding Proteins Humans Virulence Factors Bordetella Phosphorylation Protein kinase A Molecular Biology Protein Kinase C Protein kinase C Adenosine Diphosphate Ribose G protein-coupled receptor kinase MAP kinase kinase kinase Brain Cell Biology General Medicine Molecular Weight Pertussis Toxin Biochemistry Guanosine 5'-O-(3-Thiotriphosphate) Guanosine Triphosphate Protein Kinases Protein Processing Post-Translational |
| Zdroj: | Molecular and Cellular Biochemistry. 107:65-77 |
| ISSN: | 1573-4919 0300-8177 |
| DOI: | 10.1007/bf02424577 |
| Popis: | Three G proteins from human brain membranes were purified to near homogeneity by conventional techniques including preparative electrophoresis. These G proteins were characterized by their ability to bind GTP, GDP and GTP analogs. Two of these proteins have molecular weights of 50,000 (G50) and 36,000 (G36), as determined on SDS-gels. G36 was ADP-ribosylated by pertussis toxin. Thus, G50 could represent a Gs alpha subunit, whereas G36 could be Gi alpha or Go alpha. G50 was phosphorylated by cAMP dependent protein kinase and protein kinase C. G36 was phosphorylated by a protein kinase independent of calcium and phospholipid, a proteolytic product of protein kinase C, analogous to protein kinase M. Phosphorylation of G36 by this protein kinase induced a dramatic decrease in its GTPase activity. The third G protein, of molecular weight 22,000 probably belongs to the group of monomeric G proteins possessing functional similarities with ras gene products. The regulation of G proteins involving calcium-dependent and independent pathways is delineated. |
| Databáze: | OpenAIRE |
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