| First Author | Anderson AA | Year | 2006 |
| Journal | J Cell Sci | Volume | 119 |
| Issue | Pt 10 | Pages | 2145-55 |
| PubMed ID | 16638807 | Mgi Jnum | J:108926 |
| Mgi Id | MGI:3625379 | Doi | 10.1242/jcs.02935 |
| Citation | Anderson AA, et al. (2006) The junctional SR protein JP-45 affects the functional expression of the voltage-dependent Ca2+ channel Cav1.1. J Cell Sci 119(Pt 10):2145-55 |
| abstractText | JP-45, an integral protein of the junctional face membrane of the skeletal muscle sarcoplasmic reticulum (SR), colocalizes with its Ca(2+)-release channel (the ryanodine receptor), and interacts with calsequestrin and the skeletal-muscle dihydropyridine receptor Ca(v)1. We have identified the domains of JP-45 and the Ca(v)1.1 involved in this interaction, and investigated the functional effect of JP-45. The cytoplasmic domain of JP-45, comprising residues 1-80, interacts with Ca(v)1.1. JP-45 interacts with two distinct and functionally relevant domains of Ca(v)1.1, 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 Ca(v)1 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 Ca(v)1.1 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 V(Q1/2) to a more negative potential (-10 mV). JP-45 depletion decreased both the content of Ca(v)1.1 and peak charge-movements. Our data demonstrate that JP-45 is an important protein for functional expression of voltage-dependent Ca(2+) channels. |
