Functional investigation of a putative calcium-binding site involved in the inhibition of inositol 1,4,5-trisphosphate receptor activity.

ABSTRACT: The regulation of inositol 1,4,5-trisphosphate (IP₃) receptor (IP₃R) activity is thought to define the spatiotemporal patterns of Ca²⁺ signals necessary for the appropriate activation of downstream effectors. The binding of both IP₃ and Ca²⁺ is obligatory for IP₃R channel opening. Ca²⁺ however regulates IP₃R activity in a biphasic manner. Ca²⁺ binding to a high-affinity pocket formed by the third armadillo repeat domain and linker domain promotes IP₃R channel opening without altering the Ca²⁺ dependency for channel inactivation. These data suggest that a distinct low-affinity Ca²⁺-binding site is responsible for the reduction in IP₃R activity at hig

SUBMITTER: Arige V 

PROVIDER: S-EPMC11938044 | biostudies-literature | 2025 Mar

REPOSITORIES: biostudies-literature