Structural and functional characterization of interactions between the dihydropyridine receptor II-III loop and the ryanodine receptor.
1. Excitation-contraction coupling in skeletal muscle is dependent on a physical interaction between the dihydropyridine receptor (DHPR) and the ryanodine receptor (RyR). 2. A number of peptides derived from the II-III loop region of the DHPR have been shown to be functionally active in stimulating the release of calcium via RyR channels. Their function has been found to correlate with the presence of a basic helical region located at the N-terminus of the II-III loop. 3. The entire recombinant skeletal DHPR II-III loop is an efficient activator of RyR1 and RyR2. 4. The skeletal DHPR II-III loop is comprised of a series of a-helices, but its tertiary structure has been determined to be unstructured and flexible. 5. Fluorescence quenching experiments have been used to identify and measure the binding affinity of the II-III loop with fragments of the RyR.
Casarotto
Marco G
MG
Division of Molecular Bioscience, John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital Territory, Australia. marco.casarotto@anu.edu.au
Cui
Yanfang
Y
Karunasekara
Yamuna
Y
Harvey
Peta J
PJ
Norris
Nicole
N
Board
Philip G
PG
Dulhunty
Angela F
AF
D001665:Binding Sites; D020746:Calcium Channels, L-Type / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D019837:Ryanodine Receptor Calcium Release Channel / Q000737:chemistry / Q000378:metabolism*
D020746:Calcium Channels, L-Type; D019837:Ryanodine Receptor Calcium Release Channel