Multiple interactions of PRK1 with RhoA - Functional assignment of the HR1 repeat motif
Multiple interactions of PRK1 with RhoA - Functional assignment of the HR1 repeat motif
复制标题
DOI：
10.1074/jbc.273.5.2698
复制
发表时间：
1998-01-30
影响因子：
4.8
通讯作者：
Parker, PJ
中科院分区：
文献类型：
--
作者：
Flynn, P;Mellor, H;Parker, PJ
PRK 1（PKN）是一种丝氨酸/苏氨酸激酶，已显示其被RhoA激活（Amano，M.，Mukai，H.，一个Y Chihara，K.，Matsui，T.，Hamajima，Y.，Okawa，K.，Iwamatsu，A.，和Kaibuchi，K.（1996）Science 271，648-650），参与RhoA结合的PRK 1区的详细分析揭示了HR 1结构域内的两个同源序列（HR 1a和HR 1b）均结合RhoA;该结构域内的第三个重复序列HR 1c（PRK 1）不结合RhoA，还发现相关的HR 1基序赋予RhoA结合活性给该激酶家族的唯一另一个完全克隆的成员PRK 2。此外，该基序的预测值是针对源自秀丽隐杆线虫开放阅读框的HR 1a序列建立的，该开放阅读框编码未知功能的蛋白激酶。有趣的是，HR 1a（PRK 1）和HR 1b（PRK 1）亚结构域显示出对RhoA结合的独特的核苷酸依赖性，HR 1a（PRK 1）完全是GTP依赖性的，而HR 1b（PRK 1）结合RhoA的GTP和GDP结合形式。这种区别表明，RhoA和PRK 1之间有两个接触位点，一个通过构象依赖于RhoA的核苷酸结合状态的区域接触，另一个不是。对Rho/Rac嵌合体结合的分析提供了在Rho的中心三分之一中HR 1a（PRK 1）而不是HR 1b（PRK 1）相互作用的证据。观察到V14 RhoA突变体结合HR 1a但不结合HR 1b，这种独特的结合行为证实了HR 1a（PRK 1）和HR 1b（PRK 1）基序在RhoA上存在独立接触的结论。
PRK1 (PKN) is a serine/threonine kinase that has been shown to be activated by RhoA (Amano, M., Mukai, H., One, Y., Chihara, K., Matsui, T., Hamajima, Y., Okawa, K., Iwamatsu, A., and Kaibuchi, K. (1996) Science 271, 648-650), Detailed analysis of the PRK1 region involved in RhoA binding has revealed that two homologous sequences within the HR1 domain (HR1a and HR1b) both bind to RhoA; the third repeat within this domain, HR1c(PRK1), does not bind RhoA, The related HR1 motif is also found to confer RhoA binding activity to the only other fully cloned member of this kinase family, PRK2, Furthermore, the predictive value of this motif is established for an HR1a sequence derived from a Caenorhabditis elegans open reading frame encoding a protein kinase of unknown function, Interestingly, the HR1a(PRK1) and HR1b(PRK1) subdomains are shown to display a distinctive nucleotide dependence for RhoA binding, HR1a(PRK1) is entirely GTP-dependent, while HR1b(PRK1) binds both GTP-and GDP-bound forms of RhoA. This distinction indicates that there are two sites of contact between RhoA and PRK1, one contact through a region that is conformationally dependent upon the nucleotide-bound state of RhoA and one that is not, Analysis of binding to Rho/Rac chimera provides evidence for a HR1a(PRK1) but not HR1b(PRK1) interaction in the central third of Rho, Additionally, it is observed that the V14RhoA mutant binds HR1a but does not bind HR1b, This distinct binding behavior corroborates the conclusion that there are independent contacts on RhoA for the HR1a(PRK1) and HR1b(PRK1) motifs.