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

Journal Article · Sun Nov 01 04:00:00 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), Journal Name: Proc. Natl. Acad. Sci. U.S.A.; (United States) Vol. 84:21; ISSN PNASA
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBOXYLIC ACIDS
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTROPHORESIS
EVEN-ODD NUCLEI
HEXADECANOIC ACID
IMMUNE SERUMS
ISOTOPES
LABELLED COMPOUNDS
LIGHT NUCLEI
LIPIDS
LIPOTROPIC FACTORS
MAMMALS
MAN
METHIONINE
MONOCARBOXYLIC ACIDS
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PRECIPITATION
PRIMATES
PROTEINS
PURIFICATION
RADIOISOTOPES
SEPARATION PROCESSES
SULFUR 35
SULFUR ISOTOPES
TETRADECANOIC ACID
TRITIUM COMPOUNDS
TUMOR CELLS
VERTEBRATES