1995 Fiscal Year Final Research Report Summary
Localization and functional difference of various betagamma subunits of G protein
| Project/Area Number |
06680639
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Functional biochemistry
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| Research Institution | Institute for Developmental Research, Aichi Human Service Center |
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Principal Investigator |
ASANO Tomiko Institute for Developmental Research Department of Biochemistry Section Head, 生化学, 室長 (70100154)
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| Co-Investigator(Kenkyū-buntansha) |
MORISHITA Rika Institute for Developmental Research Aichi Human Service Center Department of Bi, 生化学, 研究助手
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| Project Period (FY) |
1994 – 1995
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| Keywords | G Protein / gamma subunit / Primary structure / Protein kinase C / Phosphorylation / Tissue distribution |
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| Research Abstract |
We have determined the primary structure of a novel gamma subunit (gamma12, previously designated gammaS1) of G protein purified from bovine spleen. The mature gamma12 protein composed of 68 amino acids had acetylated serine at the N-terminus and geranylgeranylated/carboxylmethylated cysteine at the Cterminus. This was consistent with the C-terminal prenylation signal in the amino acid sequence which was predicted from gamma12 cDNA isolated from a bovine spleen cDNA library. Among various gamma subunits (gamma1, gamma2, gamma3, gamma7 and gamma12), gamma12 has a unique property to be phosphorylated by protein kinase C.The phosphorylated amino acid residue was Ser1 (or Ser2). Exposure of Swiss 3T3 and aortic smooth muscle cells to phorbol 12-myristate 13-acetate ane NaF induced phosphorylation of gamma12.Stimulation of aortic smooth muscle cells with natural vasoactive agents such as angiotensin II and vasopressin also induced phosphorylation of gamma12. The extent of phosphorylation of betagamma12 in vitro was suppressed by a complex formation with Goalpha, which was relieved by the addition of GTPgammaS or aluminum fluoride. These results strongly suggest that gamma12 is phosphorylated by protein kinase C during activation of receptor (s) and G protein (s) in living cells. Then the localization of various forms of the gamma subunit of G protein was investigated by the use of antibodies against the respective gamma subunits. The gamma3 was expressed in neuronal cells, and gamma12 was the major gamma subunit in most nonneural cells. gamma2, gamma5 and gamma12 were distributed in a variety of tissues, but gamma2 was dominant in the brain.
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