Referenced in: none

Automatically associated channels: Cav2.1

Title: Conversion of an inactive cardiac dihydropyridine receptor II-III loop segment into forms that activate skeletal ryanodine receptors.

Authors: X Zhu, G Gurrola, M T Jiang, J W Walker, H H Valdivia

Journal, date & volume: FEBS Lett., 1999 May 7 , 450, 221-6

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/10359078

Abstract
A 25 amino acid segment (Glu666-Pro691) of the II-III loop of the alpha1 subunit of the skeletal dihydropyridine receptor, but not the corresponding cardiac segment (Asp788-Pro814), activates skeletal ryanodine receptors. To identify the structural domains responsible for activation of skeletal ryanodine receptors, we systematically replaced amino acids of the cardiac II-III loop with their skeletal counterparts. A cluster of five basic residues of the skeletal II-III loop (681RKRRK685) was indispensable for activation of skeletal ryanodine receptors. In the cardiac segment, a negatively charged residue (Glu804) appears to diminish the electrostatic potential created by this basic cluster. In addition, Glu800 in the group of negatively charged residues 798EEEEE802 of the cardiac II-III loop may serve to prevent the binding of the activation domain.