module: dmel_crac_channel_complex
title: CRAC channel (Stim-Orai) complex in Drosophila melanogaster
label: CRAC channel complex
module_type: PROTEIN_COMPLEX
description: >-
  The calcium release-activated calcium (CRAC) channel mediates
  store-operated calcium entry. Stim is a single-pass endoplasmic reticulum
  membrane protein whose luminal EF-hand senses ER calcium; when ER stores
  are depleted, Stim oligomerises, moves to ER-plasma membrane junctions and
  binds and opens Orai, the pore-forming plasma membrane channel subunit. Stim
  and Orai were identified in Drosophila S2 cell RNAi screens as essential for
  store-operated calcium entry.
summary: >-
  Stim ER calcium sensor and Orai plasma membrane pore that together mediate
  store-operated calcium entry.
concepts:
  - {id: GO:0034704, label: calcium channel complex}
group: CRAC
roles:
  Orai: pore-forming plasma membrane subunit
  Stim: ER calcium sensor and channel activator
unit_functions:
  Orai: {id: GO:0015279, label: store-operated calcium channel activity}
  Stim: {id: GO:0005246, label: calcium channel regulator activity}
notes: >-
  GO has no specific term for the CRAC channel complex, so the parent term
  calcium channel complex is used. Stim and Orai sit in different membranes
  and interact at ER-plasma membrane junctions after store depletion.