Mitsugumin 53-mediated maintenance of K+ currents in cardiac myocytes

Haruko Masumiya, Yasuhide Asaumi, Miyuki Nishi, Susumu Minamisawa, Satomi Adachi-Akahane, Morikatsu Yoshida, Kenji Kangawa, Kenta Ito, Yutaka Kagaya, Teruyuki Yanagisawa, Tetsuo Yamazaki, Jianjie Ma, Hiroshi Takeshima

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


Mitsugumin 53 (MG53) is a muscle-specific RBCC/TRIM family member predominantly localized on small vesicles underneath the plasma membrane. Upon cell-surface lesion MG53 recruits the vesicles to the repair site in an oxidation-dependent manner and MG53-knockout mice develop progressive myopathy associated with defective membrane repair. In this report, we focus on MG53-knockout cardiomyocytes showing abnormal action potential profile and a reduced K+ current density. In cDNA expression experiments using cultured cells, KV2.1-mediated currents were remarkably increased by MG53 without affecting the total and cell-surface levels of channel expression. In imaging analysis MG53 seemed to facilitate the mobility of K V2.1-containing endocytic vesicles with acidic pH. However, similar effects on the current density and vesicular mobility were not observed in the putative dominant-negative form of MG53. Our data suggest that MG53 is involved in a constitutive cycle of certain cell-surface proteins between the plasma membrane and endosome-like vesicles in striated muscle, and also imply that the vesicular dynamics are essential for the quality control of KV2.1 in cardiomyocytes.

Original languageEnglish
Pages (from-to)6-11
Number of pages6
Issue number1
Publication statusPublished - 2009
Externally publishedYes


  • Cardiac muscle
  • K2.1
  • Membrane recycling
  • Membrane repair
  • Mitsugumin 53
  • RBCC/TRIM family
  • Vesicular trafficking

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry


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