title: Ca²⁺ microdomains organized by junctophilins.
abstract: Excitable cells typically possess junctional membrane complexes (JMCs) constructed by the plasma membrane and the endo/sarcoplasmic reticulum (ER/SR) for channel crosstalk. These JMCs are termed triads in skeletal muscle, dyads in cardiac muscle, peripheral couplings in smooth and developing striated muscles, and subsurface cisterns in neurons. Junctophilin subtypes contribute to the formation and maintenance of JMCs by serving as a physical bridge between the plasma membrane and ER/SR membrane in different cell types. In muscle cells, junctophilin deficiency prevents JMC formation and functional crosstalk between cell-surface Ca(2+) channels and ER/SR Ca(2+) release channels. Human genetic mutations in junctophilin subtypes are linked to congenital hypertrophic cardiomyopathy and neurodegenerative diseases. Furthermore, growing evidence suggests that dysregulation of junctophilins induces pathological alterations in skeletal and cardiac muscle.
authors: Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan. Electronic address: takeshim@pharm.kyoto-u.ac.jp.
authors: Hiroshi
authors: H
authors: Takeshima
authors: Department of Medicine and Center for Research in Biological Systems, University of California, San Diego, CA 92093, USA. Electronic address: mhoshijima@ucsd.edu.
authors: Masahiko
authors: M
authors: Hoshijima
authors: Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA. Electronic address: long-sheng-song@uiowa.edu.
authors: Long-Sheng
authors: LS
authors: Song
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000502:physiology*; D002462:Cell Membrane / Q000378:metabolism*; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*
chemical_list: D008565:Membrane Proteins; C412507:junctophilin; D002118:Calcium
keywords: Calcium channel; Excitation–contraction coupling; Muscle