Highly cooperative and hysteretic response of the skeletal muscle ryanodine receptor to changes in proton concentrations.

AUTOR(ES)

Ma, J

RESUMO

Ryanodine receptors are key molecules in excitation-contraction coupling of skeletal muscle. They form the pore of the calcium release channel, which is regulated by Ca and ATP. Multiple proton titration sites are involved in controlling the different open states of the channel, as indicated by the following: i) the channel had a biphasic response to changes in proton concentrations around neutral pH; ii) the activities of the channel were inhibited by acidic pHs in a highly cooperative manner; and iii) the channel exhibited pronounced hysteresis to changes in pH. Four distinct conductance states can be identified in the single ryanodine-activated calcium release channel. The distribution of the multiple conductance states depends on the level of [Ca], ATP, and pH in the recording solution. The data are consistent with the multimeric structure of the skeletal muscle ryanodine receptor.

Documentos Relacionados

• Chicken skeletal muscle ryanodine receptor isoforms: ion channel properties.
• Postpartum changes to maternal blood lead concentrations.
• Calmodulin activation and inhibition of skeletal muscle Ca2+ release channel (ryanodine receptor).
• Biochemical evidence for a complex involving dihydropyridine receptor and ryanodine receptor in triad junctions of skeletal muscle.
• Abnormal junctions between surface membrane and sarcoplasmic reticulum in skeletal muscle with a mutation targeted to the ryanodine receptor.