FHL3 is an actin-binding protein that regulates α-actinin-mediated actin bundling -: FHL3 localizes to actin stress fibers and enhances cell spreading and stress fiber disassembly
FHL3 is an actin-binding protein that regulates α-actinin-mediated actin bundling -: FHL3 localizes to actin stress fibers and enhances cell spreading and stress fiber disassembly
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DOI：
10.1074/jbc.m213259200
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发表时间：
2003-06-27
影响因子：
4.8
通讯作者：
Mitchell, CA
中科院分区：
文献类型：
--
作者：
Coghill, ID;Brown, S;Mitchell, CA
四个半LIM结构域(FHL)蛋白是LIM蛋白超家族的成员。一些FHL蛋白作为CREM/CREB转录因子和雄激素受体的共同激活因子发挥作用。FHL3在骨骼肌中高表达，但其功能尚不清楚。在C2C12成肌细胞中，FHL3定位于细胞核，整合素结合后，FHL3离开细胞核，定位于肌动蛋白应激纤维和灶性粘连。在成熟骨骼肌中，FHL3位于Z线。肌动蛋白被确定为一个潜在的FHL3结合伙伴在酵母双杂交筛选骨骼肌文库。谷胱甘肽S转移酶下拉实验和重组蛋白与内源蛋白的免疫共沉淀表明，FHL3在体内外均与肌动蛋白形成络合。FHL3促进细胞伸展，当在伸展的C2C12细胞中过表达时，会破坏肌动蛋白应激纤维。与非运动性细胞相比，迁移到人工伤口中的高运动性细胞中FHL3的表达增加。用低速肌动蛋白共沉淀法和电子显微镜对FHL3诱导肌动蛋白应激纤维解体的分子机制进行了研究。FHL3抑制α-肌动蛋白介导的肌动蛋白捆绑。这些研究表明，FHL3是骨骼肌母细胞肌动蛋白细胞骨架动力学的重要调节因子。
Four and a half LIM domain (FHL) proteins are members of the LIM protein superfamily. Several FHL proteins function as co-activators of CREM/CREB transcription factors and the androgen receptor. FHL3 is highly expressed in skeletal muscle, but its function is unknown. FHL3 localized to the nucleus in C2C12 myoblasts and, following integrin engagement, exited the nucleus and localized to actin stress fibers and focal adhesions. In mature skeletal muscle FHL3 was found at the Z-line. Actin was identified as a potential FHL3 binding partner in yeast two-hybrid screening of a skeletal muscle library. FHL3 complexed with actin both in vitro and in vivo as shown by glutathione S-transferase pull-down assays and co-immunoprecipitation of recombinant and endogenous proteins. FHL3 promoted cell spreading and when overexpressed in spread C2C12 cells disrupted actin stress fibers. Increased FHL3 expression was detected in highly motile cells migrating into an artificial wound, compared with non-motile cells. The molecular mechanism by which FHL3 induced actin stress fiber disassembly was demonstrated by low speed actin co-sedimentation assays and electron microscopy. FHL3 inhibited alpha-actinin-mediated actin bundling. These studies reveal FHL3 as a significant regulator of actin cytoskeletal dynamics in skeletal myoblasts.