Myosin Light Chain Kinase (MLCK) Regulates Cell Migration in a Myosin Regulatory Light Chain Phosphorylation-independent Mechanism
Myosin Light Chain Kinase (MLCK) Regulates Cell Migration in a Myosin Regulatory Light Chain Phosphorylation-independent Mechanism
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肌球蛋白轻链激酶 (MLCK) 通过肌球蛋白调节轻链磷酸化独立机制调节细胞迁移
DOI：
10.1074/jbc.m114.567446
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发表时间：
2014-10-10
影响因子：
4.8
通讯作者：
Zhu, Min-Sheng
中科院分区：
文献类型：
--
作者：
Chen, Chen;Tao, Tao;Zhu, Min-Sheng
肌球蛋白轻链激酶（MLCK）长期以来一直参与肌球蛋白磷酸化和细胞迁移所需的力的产生。在此，我们惊奇地发现MLCK的缺失导致快速细胞迁移，增强突起形成，并且肌球蛋白轻链磷酸化没有改变。突变细胞表现出膜束缚力降低和膜F-肌动蛋白丝减少。这种表型被激酶死亡的MLCK或5-DFRXXL基序（一种具有有效F-肌动蛋白结合活性的MLCK片段）拯救。下拉和免疫共沉淀试验表明，MLCK的情况下，导致衰减形成的跨膜复合物，包括肌球蛋白II，整合素和纤连蛋白。我们认为，MLCK是不需要肌球蛋白磷酸化在迁移细胞。MLCK在细胞迁移中的关键作用包括调节迁移所需的细胞膜张力和突起，从而通过F-肌动蛋白结合活性稳定膜骨架。这一发现揭示了细胞迁移过程中突起的一种新的调节机制。
Myosin light chain kinase (MLCK) has long been implicated in the myosin phosphorylation and force generation required for cell migration. Here, we surprisingly found that the deletion of MLCK resulted in fast cell migration, enhanced protrusion formation, and no alteration of myosin light chain phosphorylation. The mutant cells showed reduced membrane tether force and fewer membrane F-actin filaments. This phenotype was rescued by either kinase-dead MLCK or five-DFRXXL motif, a MLCK fragment with potent F-actin-binding activity. Pull-down and co-immunoprecipitation assays showed that the absence of MLCK led to attenuated formation of transmembrane complexes, including myosin II, integrins and fibronectin. We suggest that MLCK is not required for myosin phosphorylation in a migrating cell. A critical role of MLCK in cell migration involves regulating the cell membrane tension and protrusion necessary for migration, thereby stabilizing the membrane skeleton through F-actin-binding activity. This finding sheds light on a novel regulatory mechanism of protrusion during cell migration.