Role of myosin-II phosphorylation in V12Cdc42-mediated disruption of Drosophila cellularization.
Role of myosin-II phosphorylation in V12Cdc42-mediated disruption of Drosophila cellularization.
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肌球蛋白-II 磷酸化在 V12Cdc42 介导的果蝇细胞化破坏中的作用。
DOI：
10.1078/0171-9335-00156
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
Kiehart,DP
中科院分区：
文献类型：
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作者：
Crawford,JM;Su,Z;Varlamova,O;Bresnick,AR;Kiehart,DP
显微注射组成型活性Cdc 42（V12 Cdc 42）在细胞化过程中破坏肌动球蛋白细胞骨架（Crawford等人，Dev.生物学：204，151 - 164（1998））。丝氨酸/苏氨酸激酶的p21激活激酶（PAK）家族是小GTP酶Cdc 42和Rac的GTP结合形式的效应物。果蝇PAK，与肌动蛋白和肌球蛋白-II在细胞化过程中共定位，集中在V12 Cdc 42诱导的肌动球蛋白中断的网站。体外生化分析表明，PAK磷酸化的调节轻链（RLC）的果蝇非肌肉肌球蛋白-II的丝氨酸21，一个网站已知激活肌球蛋白-II的功能。虽然激活的PAK不破坏肌动球蛋白细胞骨架，它诱导Ser 21磷酸化RLC的水平增加。这些发现表明，RLC磷酸化水平的增加并不有助于破坏肌动球蛋白六边形阵列。
Microinjection of constitutively active Cdc42 (V12Cdc42) disrupts the actomyosin cytoskeleton during cellularization (Crawford et al., Dev. Biol., 204, 151 – 164 (1998)). The p21-activated kinase (PAK) family of Ser/Thr kinases are effectors of GTP-bound forms of the small GTPases, Cdc42 and Rac. Drosophila PAK, which colocalizes with actin and myosin-II during cellularization, concentrates at sites of V12Cdc42-induced actomyosin disruption. In vitro biochemical analyses demonstrate that PAK phosphorylates the regulatory light chain (RLC) of Drosophila nonmuscle myosin-II on Ser21, a site known to activate myosin-II function. Although activated PAK does not disrupt the actomyosin cytoskeleton, it induces increased levels of Ser21 phosphorylated RLC. These findings suggest that increased levels of RLC phosphorylation do not contribute to disruption of the actomyosin hexagonal array.