The essential mitotic peptidyl-prolyl isomerase Pin1 binds and regulates mitosis-specific phosphoproteins
The essential mitotic peptidyl-prolyl isomerase Pin1 binds and regulates mitosis-specific phosphoproteins
复制标题
DOI：
10.1101/gad.12.5.706
复制
发表时间：
1998-03-01
影响因子：
10.5
通讯作者：
Lu, KP
中科院分区：
文献类型：
--
作者：
Shen, MH;Stukenberg, PT;Lu, KP
丝氨酸/苏氨酸-脯氨酸基序上有丝分裂蛋白的磷酸化已被证明在调节有丝分裂进程中起重要作用。Pin 1是一种新的必需肽基脯氨酰异构酶（PPI酶），抑制进入有丝分裂，也需要通过有丝分裂的适当进展，但其底物（S）和功能（S）仍有待确定。在这里，我们报告说，在人类细胞和爪蟾提取物，Pin 1直接与有丝分裂磷蛋白的磷酸化丝氨酸/苏氨酸-Pro基序的磷酸化依赖性和有丝分裂特异性的方式与一个子集。这些Pin 1结合蛋白中的许多也被单克隆抗体MPM-2识别，它们包括重要的有丝分裂调节因子Cdc 25、Myt 1、Wee 1、Plk 1和Cdc 27。这种Pin 1相互作用的重要性进行了测试，通过构建两个Pin 1活性位点点突变体，不能结合磷酸化的丝氨酸/苏氨酸-脯氨酸基序在有丝分裂磷蛋白。野生型，但不是突变体，Pin 1抑制有丝分裂在非洲爪蟾胚胎和进入有丝分裂在非洲爪蟾提取物。我们详细研究了Pin 1和Cdc 25之间的相互作用。Pin 1不仅结合Cdc 25的有丝分裂形式的磷酸化位点上，其在体外和体内的活性是重要的，但它也抑制其活性，提供了一个解释Pin 1抑制有丝分裂进入的能力。在另一篇论文中，我们已经证明Pin 1是一种磷酸化依赖性PPI酶，可以特异性识别有丝分裂磷蛋白中存在的磷酸化Ser/Thr-Pro键。因此，Pin 1可能作为一个通用的有丝分裂蛋白，已被Cdc 2和其他有丝分裂激酶磷酸化的调节器。
Phosphorylation of mitotic proteins on the Ser/Thr-Pro motifs has been shown to play an important role in regulating mitotic progression. Pin1 is a novel essential peptidyl-prolyl isomerase (PPIase) that inhibits entry into mitosis and is also required for proper progression through mitosis, but its substrate(s) and function(s) remain to be determined. Here we report that in both human cells and Xenopus extracts, Pin1 interacts directly with a subset of mitotic phosphoproteins on phosphorylated Ser/Thr-Pro motifs in a phosphorylation-dependent and mitosis-specific manner. Many of these Pin1-binding proteins are also recognized by the monoclonal antibody MPM-2, and they include the important mitotic regulators Cdc25, Myt1, Wee1, Plk1, and Cdc27. The importance of this Pin1 interaction was tested by constructing two Pin1 active site point mutants that fail to bind a phosphorylated Ser/Thr-Pro motif in mitotic phosphoproteins. Wild-type, but not mutant, Pin1 inhibits both mitotic division in Xenopus embryos and entry into mitosis in Xenopus extracts. We have examined the interaction between Pin1 and Cdc25 in detail. Pin1 not only binds the mitotic form of Cdc25 on the phosphorylation sites important for its activity in vitro and in vivo, but it also inhibits its activity, offering one explanation for the ability of Pin1 to inhibit mitotic entry. In a separate paper, we have shown that Pin1 is a phosphorylation-dependent PPIase that can recognize specifically the phosphorylated Ser/Thr-Pro bonds present in mitotic phosphoproteins. Thus, Pin1 likely acts as a general regulator of mitotic proteins that have been phosphorylated by Cdc2 and other mitotic kinases.