LIMCH1 regulates nonmuscle myosin-II activity and suppresses cell migration.
LIMCH1 regulates nonmuscle myosin-II activity and suppresses cell migration.
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DOI：
10.1091/mbc.e15-04-0218
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发表时间：
2017-04-15
影响因子：
3.3
通讯作者：
Pai LM
中科院分区：
文献类型：
--
作者：
Lin YH;Zhen YY;Chien KY;Lee IC;Lin WC;Chen MY;Pai LM
LIMCH1特异地与收缩应力纤维相关。LIMCH1的n端直接与NM-IIA的头部相互作用。LIMCH1缺失调节肌球蛋白调节轻链和FAK磷酸化。在limch1缺失的细胞中，肌动蛋白应激纤维和局灶黏附减少，导致细胞迁移增加。非肌球蛋白II （non - muscle myosin II, NM-II）是参与细胞迁移的重要运动蛋白。将NM-II掺入肌动蛋白应力纤维中可提供牵引力，促进肌动蛋白逆行流动和黏附聚集。然而，参与调节纳米- ii活性的成分尚不清楚。在这里，我们发现了一种新的肌动蛋白应激纤维相关蛋白，LIM和钙钙蛋白同源结构域1 (LIMCH1)，它调节NM-II的活性。LIMCH1在收缩应力纤维中的招募表明其定位与肌动蛋白-1互补。LIMCH1与NM-IIA相互作用，而不与NM-IIB相互作用，独立于blebbistatin对肌球蛋白atp酶活性的抑制。此外，LIMCH1的n端与NM-IIA的头部区域结合。在HeLa细胞中，LIMCH1的缺失减弱了肌球蛋白调节轻链（MRLC）的二磷酸化，通过小干扰rna抗性LIMCH1的重新表达恢复了这一磷酸化。此外，limch1缺失的HeLa细胞表现出肌动蛋白应激纤维数量减少和局灶粘连，导致细胞迁移增强。总之，我们的数据表明，在细胞迁移过程中，LIMCH1通过对MRLC的影响，在调节NM-II活性方面发挥了积极作用。
LIMCH1 specifically associates with contractile stress fibers. The N-terminus of LIMCH1 directly interacts with the head of NM-IIA. LIMCH1 depletion modulates the myosin regulatory light chain and FAK phosphorylation. Actin stress fiber and focal adhesion are decreased in LIMCH1-depleted cells, leading to increased cell migration. Nonmuscle myosin II (NM-II) is an important motor protein involved in cell migration. Incorporation of NM-II into actin stress fiber provides a traction force to promote actin retrograde flow and focal adhesion assembly. However, the components involved in regulation of NM-II activity are not well understood. Here we identified a novel actin stress fiber–associated protein, LIM and calponin-homology domains 1 (LIMCH1), which regulates NM-II activity. The recruitment of LIMCH1 into contractile stress fibers revealed its localization complementary to actinin-1. LIMCH1 interacted with NM-IIA, but not NM-IIB, independent of the inhibition of myosin ATPase activity with blebbistatin. Moreover, the N-terminus of LIMCH1 binds to the head region of NM-IIA. Depletion of LIMCH1 attenuated myosin regulatory light chain (MRLC) diphosphorylation in HeLa cells, which was restored by reexpression of small interfering RNA–resistant LIMCH1. In addition, LIMCH1-depleted HeLa cells exhibited a decrease in the number of actin stress fibers and focal adhesions, leading to enhanced cell migration. Collectively, our data suggest that LIMCH1 plays a positive role in regulation of NM-II activity through effects on MRLC during cell migration.