p21ras is modified by a farnesyl isoprenoid

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摘要：

Association of oncogenic ras proteins with cellular membranes appears to be a crucial step in transformation. ras is synthesized as a cytosolic precursor, which is processed to a mature form that localizes to the plasma membrane. This processing involves, in part, a conserved sequence, Cys-Ali-Ali-Xaa (in which Ali is an amino acid with an aliphatic side chain and Xaa is any amino acid), at the COOH terminus of ras proteins. Yeast a-factor mating hormone precursor also possesses a COOH-terminal Cys-Ali-Ali-Xaa sequence. However, while the COOH-terminal cysteine has been implicated as a site of palmitoylation of ras proteins, in mature a-type mating factor this residue is modified by an isoprenoid, a farnesyl moiety. We asked whether the Cys-Ali-Ali-Xaa sequence signaled different modifications for the yeast peptides (farnesylation) than for ras proteins (palmitoylation) or whether ras proteins were similar to the mating factors and contained a previously undiscovered isoprenoid. We report here that the processing of ras proteins involves addition of a farnesyl moiety, apparently at the COOH-terminal cysteine analogous to the cysteine modified in the yeast peptides, and that farnesylation may be important for membrane association and transforming activity of ras proteins.

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关键词：

Biochemistry Palmitate Transformation Carboxyl-Terminal Processing Membrane Localization Isoprenylation

DOI：

10.1073/pnas.86.21.8323

被引量：

1773

年份：

1989