Emerging roles of junctophilin-2 in the heart and implications for cardiac diseases

Cardiovasc Res. 2014 Jul 15;103(2):198-205. doi: 10.1093/cvr/cvu151. Epub 2014 Jun 15.

Abstract

Cardiomyocytes rely on a highly specialized subcellular architecture to maintain normal cardiac function. In a little over a decade, junctophilin-2 (JPH2) has become recognized as a cardiac structural protein critical in forming junctional membrane complexes (JMCs), which are subcellular domains essential for excitation-contraction coupling within the heart. While initial studies described the structure of JPH2 and its role in anchoring junctional sarcoplasmic reticulum and transverse-tubule (T-tubule) membrane invaginations, recent research has an expanded role of JPH2 in JMC structure and function. For example, JPH2 is necessary for the development of postnatal T-tubule in mammals. It is also critical for the maintenance of the complex JMC architecture and stabilization of local ion channels in mature cardiomyocytes. Loss of this function by mutations or down-regulation of protein expression has been linked to hypertrophic cardiomyopathy, arrhythmias, and progression of disease in failing hearts. In this review, we summarize current views on the roles of JPH2 within the heart and how JPH2 dysregulation may contribute to a variety of cardiac diseases.

Keywords: Arrhythmias; Heart failure; Junctional membrane complex; Junctophilin-2; T-tubule development.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Calcium / metabolism
  • Excitation Contraction Coupling / physiology
  • Heart / physiopathology*
  • Heart Diseases / metabolism*
  • Heart Diseases / physiopathology
  • Humans
  • Intercellular Junctions / metabolism*
  • Membrane Proteins / metabolism*

Substances

  • Membrane Proteins
  • junctophilin
  • Calcium