Repair of the plasma membrane following damage is an important aspect of normal cellular physiology, and disruption of this process is observed in many pathologic states. In a recent series of publications, we resolved that Mitsugumin 53 (MG53) is a novel, muscle-specific member of the tripartite motif/RING B-box Coiled Coil (TRIM/RBCC) family of proteins (TRIM72) that contributes to vesicle trafficking in the course of normal cellular physiology. MG53 can bind phosphatidylserine (PS) with some specificity, and interacts with caveolin-3 (Cav-3) as part of its function in vesicle trafficking.  As part of the response to membrane damage in muscle cells, MG53 acts in an oxidation-dependent manner to facilitate vesicle translocation to the sites of membrane injury where these vesicles are involved in patching the membrane. Here we discuss these findings and examine the implications of this work in the field of membrane repair. Further discussion is provided about potential therapeutic applications for MG53.

Addendum to: Cai C, Masumiya H, Weisleder N, Matsuda N, Nishi M, Hwang M, Ko JK, Lin P, Thornton A, Zhao X, Pan Z, Komazaki S, Brotto M, Takeshima H, Ma J. MG53 nucleates assembly of cell membrane repair machinery. Nat Cell Biol 2009; 11:56–64; PMID: 19043407; DOI: 10.1038/ncb1812.

Cai C, Masumiya H, Weisleder N, Pan Z, Nishi M, Komazaki S, Takeshima H, Ma J. MG53 regulates membrane budding and exocytosis in muscle cells. J Biol Chem 2009; 284:3314–22; PMID: 19029292; doi:10.1074/jbc.M808866200.

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Masumiya H, Asaumi Y, Nishi M, Minamisawa S, Adachi-Akahane S, Yoshida M, Kangawa K, Ito K, Kagaya Y, Yanagisawa T, Yamazaki T, Ma J, Takeshima H. Mitsugumin 53-mediated maintenance of K+ currents in cardiac myocytes. Channels 2009; In press.