CASEIN KINASE I-GAMMA SUBFAMILY - MOLECULAR-CLONING, EXPRESSION, AND CHARACTERIZATION OF 3 MAMMALIAN ISOFORMS AND COMPLEMENTATION OF DEFECTS IN THE SACCHAROMYCES-CEREVISIAE YCK GENES
CASEIN KINASE I-GAMMA SUBFAMILY - MOLECULAR-CLONING, EXPRESSION, AND CHARACTERIZATION OF 3 MAMMALIAN ISOFORMS AND COMPLEMENTATION OF DEFECTS IN THE SACCHAROMYCES-CEREVISIAE YCK GENES
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DOI：
10.1074/jbc.270.21.12717
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发表时间：
1995-05-26
影响因子：
4.8
通讯作者：
ROACH, PJ
中科院分区：
文献类型：
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作者：
ZHAI, LM;GRAVES, PR;ROACH, PJ
酪蛋白激酶I是最早的生物化学鉴定的蛋白激酶之一，已知在哺乳动物中以多种亚型存在。利用与CK1-Gamma亚型相对应的部分cDNA片段，克隆了三个大鼠睾丸全长cDNAs，它们定义了该亚家族的三个独立成员。命名为CK1 Gamma 1、CK1 Gamma 2和CK1 Gamma 3的亚型预测的分子质量分别为43,000、45,500和49,700。CK1伽马3也可以以可替换的剪接形式存在。这些蛋白在蛋白激酶结构域中的同源性超过90%，但与该区域内其他酪蛋白激酶I亚型的同源性只有51%-59%。通过睾丸RNA的Northern杂交检测到CK1-Gamma 1(2kb碱基)、CK1-Gamma 2(1.5和2.4kb)以及CK1-Gamma 3(2.8kb)的信息。在脑、心、肾、肺、肝和肌肉中也观察到CK1-GMA3的表达，而CK1-GMA1和CK1-GMA2的表达仅限于睾丸。三种CK1γ亚型均在大肠杆菌中以活性酶的形式表达，并进行了部分纯化。这些酶能磷酸化典型的体外酪蛋白激酶I底物，如酪蛋白、磷高磷蛋白和合成肽D4。D4肽的磷酸化被肝素激活，而蛋白质底物的磷酸化被抑制。已知的酪蛋白激酶I抑制剂CK1-7也抑制CK1γ-S，但不如CK1α或CK1β亚型有效。当与三磷酸腺苷和镁离子孵育时，三个CK1Gamma S都发生了自动磷酸化。酿酒酵母中的YCK1和YCK2基因编码酪蛋白激酶I的同源物，其缺陷导致形态异常和生长停滞。哺乳动物CK1γ1或CK1γ3的表达恢复了酵母突变株的生长和正常形态，该突变株携带YCK1和YCK2的温度敏感等位基因，表明酵母YCK蛋白和这些CK1亚型之间的功能重叠。
Casein kinase I, one of the first protein kinases identified biochemically, is known to exist in multiple isoforms in mammals. Using a partial cDNA fragment corresponding to an isoform termed CK1 gamma, three full-length rat testis cDNAs were cloned that defined three separate members of this subfamily. The isoforms, designated CK1 gamma 1, CK1 gamma 2, and CK1 gamma 3, have predicted molecular masses of 43,000, 45,500, and 49,700. CK1 gamma 3 may also exist in an alternatively spliced form. The proteins are more than 90% identical to each other within the protein kinase domain but only 51-59% identical to other casein kinase I isoforms within this region. Messages for CK1 gamma 1 (2 kilobases (kb)), CK1 gamma 2 (1.5 and 2.4 kb), and CK1 gamma 3 (2.8 kb) were detected by Northern hybridization of testis RNA. Message for CK1 gamma 3 was also observed in brain, heart, kidney, lung, liver, and muscle whereas CK1 gamma 1 and CK1 gamma 2 messages were restricted to testis. All three CK1 gamma isoforms were expressed as active enzymes in Escherichia coli and partially purified. The enzymes phosphorylated typical in vitro casein kinase I substrates such as casein, phosvitin, and a synthetic peptide, D4. Phosphorylation of the D4 peptide was activated by heparin whereas phosphorylation of the protein substrates was inhibited. The known casein kinase I inhibitor CK1-7 also inhibited the CK1 gamma s although less effectively than the CK1 alpha or CK1 delta isoforms. All three CK1 gamma s underwent autophosphorylation when incubated with ATP and Mg2+. The YCK1 and YCK2 genes in Saccharomyces cerevisiae encode casein kinase I homologs, defects in which lead to aberrant morphology and growth arrest. Expression of mammalian CK1 gamma 1 or CK1 gamma 3 restored growth and normal morphology to a yeast mutant carrying a disruption of YCK1 and a temperature-sensitive allele of YCK2, suggesting overlap of function between the yeast Yck proteins and these CK1 isoforms.