KRAP tethers IP₃ receptors to actin and licenses them to evoke cytosolic Ca²⁺ signals.

ABSTRACT: Regulation of IP₃ receptors (IP₃Rs) by IP₃ and Ca²⁺ allows regenerative Ca²⁺ signals, the smallest being Ca²⁺ puffs, which arise from coordinated openings of a few clustered IP₃Rs. Cells express thousands of mostly mobile IP₃Rs, yet Ca²⁺ puffs occur at a few immobile IP₃R clusters. By imaging cells with endogenous IP₃Rs tagged with EGFP, we show that KRas-induced actin-interacting protein (KRAP) tethers IP₃Rs to actin beneath the plasma membrane. Loss of KRAP abolishes Ca²⁺ puffs and the global increases in cytosolic Ca²⁺ concentration evoked by more intense stimulation. Over-expressing KRAP immobilizes additional IP₃R clusters

SUBMITTER: Thillaiappan NB 

PROVIDER: S-EPMC8302619 | biostudies-literature | 2021 Jul

REPOSITORIES: biostudies-literature