The junctional SR protein JP-45 affects the functional expression of the voltage-dependent Ca2+ channel Cav1.1

Anderson, Ayuk A. and Altafaj, Xavier and Zheng, Zhenlin and Wang, Zhong-Min and Delbono, Osvaldo and Ronjat, Michel and Treves, Susan and Zorzato, Francesco. (2006) The junctional SR protein JP-45 affects the functional expression of the voltage-dependent Ca2+ channel Cav1.1. Journal of Cell Science, 119 (10). pp. 2145-2155.

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Official URL: http://edoc.unibas.ch/dok/A6174315

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JP-45, an integral protein of the junctional face membrane of the skeletal muscle sarcoplasmic reticulum (SR), colocalizes with its Ca2+ -release channel (the ryanodine receptor), and interacts with calsequestrin and the skeletal-muscle dihydropyridine receptor Cav1. We have identified the domains of JP-45 and the Cav1.1 involved in this interaction, and investigated the functional effect of JP-45. The cytoplasmic domain of JP-45, comprising residues 1-80, interacts with Cav1.1. JP-45 interacts with two distinct and functionally relevant domains of Cav1.1, the I-II loop and the C-terminal region. Interaction between JP-45 and the I-II loop occurs through the alpha-interacting domain in the I-II loop. beta1a, a Cav1 subunit, also interacts with the cytosolic domain of JP-45, and its presence drastically reduces the interaction between JP-45 and the I-II loop. The functional effect of JP-45 on Cav1.1 activity was assessed by investigating charge movement in differentiated C2C12 myotubes after overexpression or depletion of JP-45. Overexpression of JP-45 decreased peak charge-movement and shifted VQ1/2 to a more negative potential (-10 mV). JP-45 depletion decreased both the content of Cav1.1 and peak charge-movements. Our data demonstrate that JP-45 is an important protein for functional expression of voltage-dependent Ca2+ channels.
Faculties and Departments:03 Faculty of Medicine > Departement Biomedizin > Department of Biomedicine, University Hospital Basel > Perioperative Patient Safety (Girard/Treves)
UniBasel Contributors:Treves, Susan
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:Company of Biologists
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:15 May 2017 07:37
Deposited On:25 Oct 2013 08:33

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