THE RETINOBLASTOMA PROTEIN IS PHOSPHORYLATED ON MULTIPLE SITES BY HUMAN CDC2
THE RETINOBLASTOMA PROTEIN IS PHOSPHORYLATED ON MULTIPLE SITES BY HUMAN CDC2
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DOI：
10.1002/j.1460-2075.1991.tb05006.x
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发表时间：
1991-12-01
期刊：
影响因子：
11.4
通讯作者：
HARLOW, E
中科院分区：
文献类型：
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作者：
LEES, JA;BUCHKOVICH, KJ;HARLOW, E
视网膜母细胞瘤基因产物（pRB）是一种核磷蛋白，被认为在细胞增殖的负调控中起关键作用。pRB以细胞周期依赖性方式磷酸化，并且在活跃分裂和分化细胞中的研究表明，这种修饰对于细胞在细胞周期中的进展可能是必需的。使用胰蛋白酶磷酸肽映射，我们已经表明，pRB是磷酸化的多个丝氨酸和苏氨酸残基在体内，许多这些磷酸化事件可以在体外使用纯化的p34cdc2模拟。使用合成肽对应于潜在的cdc2磷酸化位点，我们已经开发出一种策略，它允许识别五个网站。S249、T252、T373、S807和S811在体内被磷酸化，并且在每种情况下，这些位点与p34cdc2磷酸化的共有序列密切对应。这一点以及pRB在体内与p34cdc2形成特异性复合物的观察结果表明，p34cdc2或p34cdc2相关蛋白是主要的pRB激酶。
The retinoblastoma gene product (pRB) is a nuclear phosphoprotein that is thought to play a key role in the negative regulation of cellular proliferation. pRB is phosphorylated in a cell cycle dependent manner, and studies in both actively dividing and differentiated cells suggest that this modification may be essential for cells to progress through the cell cycle. Using tryptic phosphopeptide mapping we have shown that pRB is phosphorylated on multiple serine and threonine residues in vivo and that many of these phosphorylation events can be mimicked in vitro using purified p34cdc2. Using synthetic peptides corresponding to potential cdc2 phosphorylation sites, we have developed a strategy which has allowed the identification of five sites. S249, T252, T373, S807 and S811 are phosphorylated in vivo, and in each case these sites correspond closely to the consensus sequence for phosphorylation by p34cdc2. This and the observation that pRB forms a specific complex with p34cdc2 in vivo suggests that p34cdc2 or a p34cdc2-related protein is a major pRB kinase.