Kobashigawa Yoshihiro, Sakai Mieko, Naito Masato, Yokochi Masashi, Kumeta Hiroyuki, Makino Yoshinori, Ogura Kenji, Tanaka Shinya, Inagaki Fuyuhiko
Department of Structural Biology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan.
Nat Struct Mol Biol. 2007 Jun;14(6):503-10. doi: 10.1038/nsmb1241. Epub 2007 May 21.
CRKI (SH2-SH3) and CRKII (SH2-SH3-SH3) are splicing isoforms of the oncoprotein CRK that regulate transcription and cytoskeletal reorganization for cell growth and motility by linking tyrosine kinases to small G proteins. CRKI shows substantial transforming activity, whereas the activity of CRKII is low, and phosphorylated CRKII has no biological activity whatsoever. The molecular mechanisms underlying the distinct biological activities of the CRK proteins remain elusive. We determined the solution structures of CRKI, CRKII and phosphorylated CRKII by NMR and identified the molecular mechanism that gives rise to their activities. Results from mutational analysis using rodent 3Y1 fibroblasts were consistent with those from the structural studies. Together, these data suggest that the linker region modulates the binding of CRKII to its targets, thus regulating cell growth and motility.
CRKI（SH2-SH3）和CRKII（SH2-SH3-SH3）是癌蛋白CRK的剪接异构体，它们通过将酪氨酸激酶与小G蛋白相连来调节转录和细胞骨架重组，从而促进细胞生长和运动。CRKI具有显著的转化活性，而CRKII的活性较低，磷酸化的CRKII则完全没有生物学活性。CRK蛋白不同生物学活性背后的分子机制仍然不清楚。我们通过核磁共振确定了CRKI、CRKII和磷酸化CRKII的溶液结构，并确定了产生其活性的分子机制。使用啮齿动物3Y1成纤维细胞进行的突变分析结果与结构研究结果一致。这些数据共同表明，连接区调节CRKII与其靶标的结合，从而调节细胞生长和运动。
