Bosch T C, Unger T F, Fisher D A, Steele R E
Department of Biological Chemistry, University of California, Irvine 92717.
Mol Cell Biol. 1989 Oct;9(10):4141-51. doi: 10.1128/mcb.9.10.4141-4151.1989.
Both cDNA clones and a genomic DNA clone encoding a 509-amino-acid protein that is 64% similar to chicken pp60c-src were isolated from the simple metazoan Hydra attenuata. We have designated this gene STK, for src-type kinase. Features of the amino acid sequence of the protein encoded by the STK gene suggest that it is likely to be myristoylated and regulated by phosphorylation in a manner similar to that found for pp60c-src. The genomic sequence encoding the protein was found to be interrupted by at least two introns, one of which was located in a position identical to that of one of the introns in the chicken src gene. The STK gene was expressed during early development of H. attenuata and at high levels in the epithelial cells of adult polyps. Probing of Hydra proteins with an antibody to phosphotyrosine indicated that the major phosphotyrosine-containing protein in H. attenuata may be the STK protein itself. H. attenuata is the simplest organism from which a protein-tyrosine kinase gene has been isolated. The presence of such a gene in the evolutionarily ancient phylum Cnidaria suggests that protein-tyrosine kinase genes arose concomitantly with or shortly after the appearance of multicellular organisms.
从简单的后生动物细螅中分离出了两个cDNA克隆和一个基因组DNA克隆，它们编码一种509个氨基酸的蛋白质，该蛋白质与鸡的pp60c-src有64%的相似性。我们将这个基因命名为STK，即src型激酶。STK基因编码的蛋白质的氨基酸序列特征表明，它可能被豆蔻酰化，并以与pp60c-src类似的方式受磷酸化调节。发现编码该蛋白质的基因组序列被至少两个内含子打断，其中一个内含子的位置与鸡src基因中的一个内含子位置相同。STK基因在细螅的早期发育过程中表达，并在成年息肉的上皮细胞中高水平表达。用抗磷酸酪氨酸抗体探测细螅蛋白质表明，细螅中主要的含磷酸酪氨酸的蛋白质可能就是STK蛋白质本身。细螅是已分离出蛋白质酪氨酸激酶基因的最简单的生物体。在进化上古老的刺胞动物门中存在这样一个基因，表明蛋白质酪氨酸激酶基因是在多细胞生物出现的同时或之后不久产生的。
