Soto-Cruz I, Magee A I
Laboratory of Eukaryotic Molecular Genetics, National Institute for Medical Research, Mill Hill, London, U.K.
Biochem J. 1995 Feb 15;306 ( Pt 1)(Pt 1):11-4. doi: 10.1042/bj3060011.
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.
p21ras蛋白的羧基末端高变区在整个进化过程中高度保守，但尚未赋予其任何功能。该区域被认为可能是受体识别的候选区域。我们测试了该区域参与p21ras生物学功能的可能性。将与p21N-ras和p21K(B)-ras高变域相对应的合成肽显微注射到非洲爪蟾卵母细胞中，以评估它们对卵母细胞成熟的影响。与N-ras肽相比，K(B)-ras肽抑制胰岛素依赖性而非孕酮依赖性成熟，而N-ras肽对成熟的抑制作用不明显。一种与K(B)-ras肽氨基酸组成相同但序列混乱的对照肽以及聚（D，L-赖氨酸）均无活性。五赖氨酸具有部分活性，这可能是由于它模拟了K(B)-ras序列中富含赖氨酸的片段。这些数据支持了K(B)-ras基因产物特异性参与转导胰岛素和/或胰岛素样生长因子1信号的假说。
