title: Emerging roles of junctophilin-2 in the heart and implications for cardiac diseases.
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.
authors.affiliation: Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA Translational Biology and Molecular Medicine Program, Baylor College of Medicine, Houston, TX, USA.
authors.forename: David L
authors.initials: DL
authors.lastname: Beavers
authors.affiliation: Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Landstrom
authors.affiliation: Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA Translational Biology and Molecular Medicine Program, Baylor College of Medicine, Houston, TX, USA.
authors.forename: David Y
authors.initials: DY
authors.lastname: Chiang
authors.affiliation: Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA Deptartment of Medicine (Cardiology), Baylor College of Medicine, Houston, TX, USA wehrens@bcm.edu.
authors.forename: Xander H T
authors.initials: XH
authors.lastname: Wehrens
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D056966:Excitation Contraction Coupling / Q000502:physiology; D006321:Heart / Q000503:physiopathology*; D006331:Heart Diseases / Q000378:metabolism* / Q000503:physiopathology; D006801:Humans; D007365:Intercellular Junctions / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*
chemical_list: D008565:Membrane Proteins; C412507:junctophilin; D002118:Calcium
keywords: Arrhythmias; Heart failure; Junctional membrane complex; Junctophilin-2; T-tubule development