Myotonic dystrophy kinase-related Cdc42-binding kinase acts as a Cdc42 effector in promoting cytoskeletal reorganization
Myotonic dystrophy kinase-related Cdc42-binding kinase acts as a Cdc42 effector in promoting cytoskeletal reorganization
复制标题
DOI：
10.1128/mcb.18.1.130
复制
发表时间：
1998-01-01
影响因子：
5.3
通讯作者：
Lim, L
中科院分区：
文献类型：
--
作者：
Leung, T;Chen, XQ;Lim, L
Rho GTP酶在与生长和分化相关的细胞骨架重组中发挥独特的作用。Cdc 42/Rac结合p21激活激酶（PAK）和Rho结合激酶（ROK）作为这些GTP酶的形态效应物。我们已经分离出两种相关的新型脑激酶，其p21结合域类似于PAK，而激酶域类似于强直性肌营养不良激酶相关的ROK。那些类似于190 kDa强直性肌营养不良激酶相关Cdc 42结合激酶（MRCK）优先磷酸化非肌肉肌球蛋白轻链丝氨酸19，这是已知的激活肌动蛋白-肌球蛋白收缩性的关键。pal结合结构域结合GTP-Cdc 42但不结合GDP-Cdc 42。多结构域结构包括一个富含半胱氨酸的基序，类似于蛋白激酶C和n-嵌合蛋白的基序和一个假定的普列克底物蛋白同源结构域。MRCK α和Cdc 42（V12）共定位，特别是在转染的HeLa细胞中的细胞周边。显微注射编码MRCK α的质粒导致肌动蛋白和肌球蛋白重组。激酶死亡的MRCK α的表达阻断了Cdc 42（V12）依赖的局灶性复合物和外周微棘的形成。这不是由于p21的可能螯合，因为Cdc 42结合缺陷的激酶死亡MRCK α突变体是同样有效的阻断剂。共注射MKCK α质粒与Cdc 42质粒，在Cdc 42质粒本身不引起任何影响的浓度下，导致与Cdc 42诱导的形态表型相关的外周结构的形成。这些Cdc 42型的影响没有促进后共注射与激酶死亡或Cdc 42结合缺陷MRCK α突变体的质粒。这些结果表明，MRCK α可能作为Cdc 42在细胞骨架重组的下游效应。
The Rho GTPases play distinctive roles in cytoskeletal reorganization associated with growth and differentiation. The Cdc42/Rac-binding p21-activated kinase (PAK) and Rho-binding kinase (ROK) act as morphological effecters for these GTPases. We have isolated two related novel brain kinases whose p21-binding domains resemble that of PAK whereas the kinase domains resemble that of myotonic dystrophy kinase-related ROK. Those similar to 190-kDa myotonic dystrophy kinase-related Cdc42-binding kinases (MRCKs) preferentially phosphorylate nonmuscle myosin light chain at serine 19, which is known to be crucial for activating actin-myosin contractility. The pal-binding domain binds GTP-Cdc42 but not GDP-Cdc42. The multidomain structure includes a cysteine-rich motif resembling those of protein kinase C and n-chimaerin and a putative pleckstrin homology domain. MRCK alpha and Cdc42(V12) colocalize, particularly at the cell periphery in transfected HeLa cells. Microinjection of plasmid encoding MRCK alpha resulted in actin and myosin reorganization. Expression of kinase-dead MRCK alpha blocked Cdc42(V12)-dependent formation of focal complexes and peripheral microspikes. This was not due to possible sequestration of the p21, as a kinase-dead MRCK alpha mutant defective in Cdc42 binding was an equally effective blocker. Coinjection of MKCK alpha plasmid with Cdc42 plasmid, at concentrations where Cdc42 plasmid by itself elicited no effect, led to the formation of the peripheral structures associated with a Cdc42-induced morphological phenotype. These Cdc42-type effects were not promoted upon coinjection with plasmids of kinase-dead or Cdc42-binding-deficient MRCK alpha mutants. These results suggest that MRCK alpha may act as a downstream effector of Cdc42 in cytoskeletal reorganization.