Changes in ion channel expression and function associated with cardiac arrhythmogenic remodeling by Sorbs2

Ling Ling Qian, Xiaojing Sun, Jingchun Yang, Xiao Li Wang, Michael J. Ackerman, Ru Xing Wang, Xiaolei Xu, Hon Chi Lee, Tong Lu

Research output: Contribution to journalArticlepeer-review


The Sorbin and SH3 domain-containing protein 2 (Sorbs2) is an important component of cardiomyocyte sarcomere. It has been recently reported that loss of Sorbs2 is causally associated with arrhythmogenic cardiomyopathy in human. However, the ionic mechanisms leading to cardiac arrhythmogenesis by Sorbs2 deficiency are unknown. In this study, we hypothesized that Sorbs2 plays an important role in regulating cardiac ion channel expression and function. Using electrophysiological and molecular biological approaches, we found that the Sorbs2 knockout (KO) mice progressively developed cardiac structural and electrical remodeling as early as 1 to 2 months of age and died prematurely at 5 to 7 months of age. Electrocardiographic recordings showed that Sorbs2 KO mice had conduction delays, spontaneous ventricular extrasystoles and polymorphic ventricular tachyarrhythmia. Intracellular recordings revealed abnormal action potentials with depolarized resting potential, reduced upstroke velocity, prolonged repolarization, and effective refractory period in the ventricular preparations of Sorbs2 KO mice. Patch clamp experiments demonstrated that Sorbs2 KO mice displayed distinct abnormalities in the expression and function of cardiac ion channels, including those of the voltage-gated Na+ channels, L-type Ca2+ channels, the voltage-gated K+ channels and the inward-rectifier K+ channels. Moreover, Sorbs2 physically interacted with the RNAs and/or proteins of important cardiac ion channels and directly regulated their expression in vitro. Our results indicate that Sorbs2 plays a pivotal role in the regulation of cardiac channel physiology. Loss of Sorbs2 promotes cardiac ion channelopathies and life-threatening arrhythmias.

Original languageEnglish (US)
Article number166247
JournalBiochimica et Biophysica Acta - Molecular Basis of Disease
Issue number12
StatePublished - Dec 1 2021


  • Arrhythmia
  • Electrical remodeling
  • Ion channelopathy
  • Myocardium
  • Sorbs2

ASJC Scopus subject areas

  • Molecular Medicine
  • Molecular Biology


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