Junctophilin type 2 is associated with caveolin-3 and is down-regulated in the hypertrophic and dilated cardiomyopathies.
Functional coupling between the sarcolemmal membrane and the sarcoplasmic reticulum is based on distinct structures called junctional membrane complexes (JMCs). Recently, junctophilins are found to be responsible for normal formation of JMCs. In the present study, we found that junctophilin type 2 (JP-2), a unique isoform in the heart, was localized in caveolin-rich membranes, and that the expression of JP-2 was up-regulated during normal development and down-regulated in a hypertrophic or a dilated cardiomyopathic mouse model. The expression levels of JP-2 may be associated with the development of T-tubules and impaired Ca(2+)-induced Ca(2+) release in the heart.
Minamisawa
Susumu
S
Department of Physiology, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan. sminamis@med.yokohama-cu.ac.jp
Oshikawa
Jin
J
Takeshima
Hiroshi
H
Hoshijima
Masahiko
M
Wang
Yibin
Y
Chien
Kenneth R
KR
Ishikawa
Yoshihiro
Y
Matsuoka
Rumiko
R
D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002311:Cardiomyopathy, Dilated / Q000378:metabolism*; D002312:Cardiomyopathy, Hypertrophic / Q000378:metabolism*; D051244:Caveolin 3; D022461:Caveolins / Q000378:metabolism*; D004195:Disease Models, Animal; D015536:Down-Regulation; D018507:Gene Expression Regulation, Developmental; D006352:Heart Ventricles / Q000196:embryology* / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D008813:Mice, Inbred ICR; D008822:Mice, Transgenic / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000378:metabolism*
D015415:Biomarkers; C495548:Cav3 protein, mouse; D051244:Caveolin 3; D022461:Caveolins; D008565:Membrane Proteins; C412507:junctophilin