MUTATION OF NH-2-TERMINAL GLYCINE OF P60SRC PREVENTS BOTH MYRISTOYLATION AND MORPHOLOGICAL TRANSFORMATION
MUTATION OF NH-2-TERMINAL GLYCINE OF P60SRC PREVENTS BOTH MYRISTOYLATION AND MORPHOLOGICAL TRANSFORMATION
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DOI：
10.1073/pnas.82.14.4625
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发表时间：
1985-01-01
影响因子：
11.1
通讯作者：
SEFTON, BM
中科院分区：
文献类型：
--
作者：
KAMPS, MP;BUSS, JE;SEFTON, BM
P60src是Rous肉瘤病毒的转化蛋白激酶，含有14-C饱和脂肪酸肉豆蔻酸，通过酰胺键与其NH2末端甘氨酸残基的α-氨基相连。肉豆蔻酸已知与其他4种真核蛋白质结合。在每种情况下，脂肪酸也通过酰胺键连接到NH2末端的甘氨酸。使用寡核苷酸定向突变来检测使这些蛋白质的NH2末端肉豆蔻酰化的酶的氨基酸专一性。用丙氨酸或谷氨酸替换p60src中NH2末端的甘氨酸，完全阻止了肉豆蔻基化。这表明肉豆蔻酰化酶可能对甘氨酸具有绝对的专一性。尽管在这些细胞中观察到细胞蛋白对酪氨酸的野生型磷酸化水平，但两种非肉豆蔻酰化突变的src蛋白都没有诱导感染细胞的形态转化。由于氨基末端从甘氨酸到丙氨酸的转化对p60src的构象影响不大，因此突变的p60src蛋白不能诱导形态转化，这表明肉豆蔻基部分是该蛋白转化活性所必需的。
p60src, the transforming protein kinase of Rous sarcoma virus, contains the 14-C saturated fatty acid, myristic acid, linked through an amide bond to the .alpha.-amino group of its NH2-terminal glycine residue. Myristic acid is known to be attached to 4 other eukaryotic proteins. In each case the fatty acid is also linked through an amide bond to an NH2-terminal glycine. Oligonucleotide-directed mutagenesis was used to examine the amino acid specificity of the enzyme that myristoylates the NH2 terminus of these proteins. Replacement of the NH2-terminal glycine in p60src with either alanine or glutamic acid prevented myristoylation completely. This indicates that the myristoylating enzyme may have an absolute specificity for glycine. Neither nonmyristoylated mutant src protein induced morphological transformation of infected cells, even though wild-type levels of phosphorylation of cellular proteins on tyrosine were observed in these cells. Since conversion of the NH2-terminal residue from glycine to alanine should have little effect on the conformation of p60src, the inability of this mutant p60src protein to induce morhological transformation suggests that the myristoyl moiety is essential for the transforming activity of the protein.