鉴定有丝分裂特异性p65二聚体作为人类M期促进因子的一个组成部分。

Identification of mitosis-specific p65 dimer as a component of human M phase-promoting factor.

作者信息

Meikrantz W, Suprynowicz F A, Halleck M S, Schlegel R A

机构信息

Department of Molecular and Cell Biology, Pennsylvania State University, University Park 16802.

出版信息

Proc Natl Acad Sci U S A. 1990 Dec;87(24):9600-4. doi: 10.1073/pnas.87.24.9600.

Antisera raised against two mitosis-specific protein kinases from human cells recognized a single 65-kDa polypeptide (p65) that is present in similar amounts in interphase and mitotic cell extracts. Immunoblot analysis of reduced and unreduced extracts revealed that p65 exists as a 65-kDa monomer during interphase but forms a 130-kDa disulfide-linked homodimer during mitosis. Several different antibodies recognizing the p34cdc2 protein kinase and cyclin B components of M phase-promoting factor (MPF) coprecipitated p65 from mitotic but not from interphase extracts. In addition, an anti-p65 immunoaffinity column substantially depleted mitotic extracts of histon H1 kinase activity assayed under conditions diagnostic for MPF. These results suggest that active human MPF may be a complex of p34cdc2, cyclin B, and dimeric p65. A sulfhydryl cycle, proposed in the earlier literature on the biochemistry of mitosis, might underlie the dimerization of p65 and formation of active MPF.

针对来自人类细胞的两种有丝分裂特异性蛋白激酶产生的抗血清识别出一种单一的65 kDa多肽（p65），该多肽在间期和有丝分裂细胞提取物中的含量相似。对还原和未还原提取物的免疫印迹分析表明，p65在间期以65 kDa单体形式存在，但在有丝分裂期间形成130 kDa的二硫键连接的同源二聚体。几种识别M期促进因子（MPF）的p34cdc2蛋白激酶和细胞周期蛋白B成分的不同抗体，能从有丝分裂提取物而非间期提取物中共沉淀出p65。此外，在对MPF有诊断意义的条件下检测时，抗p65免疫亲和柱能使有丝分裂提取物中的组蛋白H1激酶活性大幅降低。这些结果表明，活性人类MPF可能是p34cdc2、细胞周期蛋白B和二聚体p65的复合物。早期关于有丝分裂生物化学的文献中提出的巯基循环，可能是p65二聚化和活性MPF形成的基础。