MG53 Regulates Membrane Budding and Exocytosis in Muscle Cells
MG53 Regulates Membrane Budding and Exocytosis in Muscle Cells
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DOI：
10.1074/jbc.m808866200
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发表时间：
2009-01-30
影响因子：
4.8
通讯作者：
Ma, Jianjie
中科院分区：
文献类型：
--
作者：
Cai, Chuanxi;Masumiya, Haruko;Ma, Jianjie
膜回收和重塑有助于多种细胞功能，包括肌生成过程中的细胞融合事件。我们鉴定了一个名为 MG53 的三联基序 (TRIM72) 家族成员蛋白，并确定了其在介导横纹肌膜融合和胞吐作用动态过程中的作用。 MG53 是一种肌肉特异性蛋白质，其氨基末端含有 TRIM 基序，羧基末端含有 SPRY 基序。培养的成肌细胞中绿色荧光蛋白-MG53 融合构建体的活细胞成像表明，尽管 MG53 不包含跨膜片段，但它与细胞内囊泡和肌膜紧密相关。 RNA 干扰介导的 MG53 表达敲低阻碍了成肌细胞分化，而 MG53 的过度表达则增强了囊泡向肌膜膜的运输和出芽。共表达研究表明 MG53 活性受到与 Caveolin-3 功能性相互作用的调节。我们的数据揭示了 TRIM 家族蛋白在调节横纹肌膜运输和融合方面的新功能。
Membrane recycling and remodeling contribute to multiple cellular functions, including cell fusion events during myogenesis. We have identified a tripartite motif (TRIM72) family member protein named MG53 and defined its role in mediating the dynamic process of membrane fusion and exocytosis in striated muscle. MG53 is a muscle-specific protein that contains a TRIM motif at the amino terminus and a SPRY motif at the carboxyl terminus. Live cell imaging of green fluorescent protein-MG53 fusion construct in cultured myoblasts showed that although MG53 contains no trans-membrane segment it is tightly associated with intracellular vesicles and sarcolemmal membrane. RNA interference-mediated knockdown of MG53 expression impeded myoblast differentiation, whereas overexpression of MG53 enhanced vesicle trafficking to and budding from sarcolemmal membrane. Co-expression studies indicated that MG53 activity is regulated by a functional interaction with caveolin-3. Our data reveal a new function for TRIM family proteins in regulating membrane trafficking and fusion in striated muscles.