title: Effect of synthetic peptides representing the hypervariable region of p21ras on Xenopus laevis oocyte maturation.
abstract: The carboxy-terminal hypervariable regions of p21ras proteins have been highly conserved throughout evolution but no function has been assigned to them yet. This region has been suggested as a possible candidate for receptor recognition. We have tested the possibility of this region being involved in p21ras biological function. Synthetic peptides corresponding to the hypervariable domains of p21N-ras and p21K(B)-ras were microinjected into Xenopus oocytes to assess their effect on oocyte maturation. The K(B)-ras peptide inhibited insulin-dependent but not progesterone-dependent maturation, in contrast with the N-ras peptide which did not inhibit maturation significantly. A control peptide, with the same amino acid composition as the K(B)-ras peptide but with a scrambled sequence, and poly(D,L-lysine) were inactive. Pentalysine had partial activity which may be due to its mimicking the lysine-rich stretch of the K(B)-ras sequence. The data support the hypothesis that the K(B)-ras gene product specifically is involved in transducing the insulin and/or insulin-like growth factor 1 signal.
authors.affiliation: Laboratory of Eukaryotic Molecular Genetics, National Institute for Medical Research, Mill Hill, London, U.K.
authors.forename: I
authors.initials: I
authors.lastname: Soto-Cruz
authors.forename: A I
authors.initials: AI
authors.lastname: Magee
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D005260:Female; D007328:Insulin / Q000494:pharmacology; D008845:Microinjections; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000494:pharmacology; D009865:Oocytes / Q000187:drug effects* / Q000502:physiology; D010446:Peptide Fragments / Q000737:chemistry / Q000494:pharmacology*; D011107:Polylysine / Q000494:pharmacology; D011374:Progesterone / Q000494:pharmacology; D016283:Proto-Oncogene Proteins p21(ras) / Q000737:chemistry / Q000494:pharmacology*; D014982:Xenopus laevis
chemical_list: D007328:Insulin; D009842:Oligopeptides; D010446:Peptide Fragments; C026591:pentalysine; D011107:Polylysine; D011374:Progesterone; D016283:Proto-Oncogene Proteins p21(ras)