Myristoylated. cap alpha. subunits of guanine nucleotide-binding regulatory proteins

Journal Article · Sun Nov 01 00:00:00 EST 1987 · Proc. Natl. Acad. Sci. U.S.A.; (United States)

DOI:https://doi.org/10.1073/pnas.84.21.7493· OSTI ID:7075575

Buss, J E; Mumby, S M; Casey, P J; Gilman, A G; Sefton, B M

Antisera directed against specific subunits of guanine nucleotide-binding regulatory proteins (G proteins) were used to immunoprecipitate these polypeptides from metabolically labeled cells. This technique detects, in extracts of a human astrocytoma cell line, the ..cap alpha.. subunits of G/sub s/ (stimulatory) (..cap alpha../sub 45/ and ..cap alpha../sub 52/), a 41-kDa subunit of G/sub i/ (inhibitory) (..cap alpha../sub 41/), a 40-kDa protein (..cap alpha../sub 40/), and the 36-kDa ..beta.. subunit. No protein that comigrated with the ..cap alpha.. subunit of G/sup 0/ (unknown function) (..cap alpha../sub 39/) was detected. In cells grown in the presence of (/sup 3/H)myristic acid, ..cap alpha../sub 41/ and ..cap alpha../sub 40/ contained /sup 3/H label, while the ..beta.. subunit did not. Chemical analysis of lipids attached covalently to purified ..cap alpha../sub 41/ and ..cap alpha../sub 39/ from bovine brain also revealed myristic acid. Similar analysis of brain G protein ..beta.. and ..gamma.. subunits and of G/sub t/ (Transducin) subunits (..cap alpha.., ..beta.., and ..gamma..) failed to reveal fatty acids. The fatty acid associated with ..cap alpha../sub 41/ , ..cap alpha../sub 40/, and ..cap alpha../sub 39/ was stable to treatment with base, suggesting that the lipid is linked to the polypeptide via an amide bond. These GTP binding proteins are thus identified as members of a select group of proteins that contains myristic acid covalently attached to the peptide backbone. Myristate may play an important role in stabilizing interactions of G proteins with phospholipid or with membrane-bound proteins.

• Research Organization: La Jolla Cancer Research Foundation, CA (USA)
• OSTI ID: 7075575
• Journal Information: Proc. Natl. Acad. Sci. U.S.A.; (United States), Vol. 84:21
• Country of Publication: United States
• Language: English

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PURIFICATION
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ELECTROPHORESIS
HEXADECANOIC ACID
IMMUNE SERUMS
LIPIDS
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SULFUR 35
TETRADECANOIC ACID
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DRUGS
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LABELLED COMPOUNDS
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LIPOTROPIC FACTORS
MAMMALS
MONOCARBOXYLIC ACIDS
NUCLEI
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ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PRIMATES
RADIOISOTOPES
SEPARATION PROCESSES
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550201* - Biochemistry- Tracer Techniques