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. Author manuscript; available in PMC: 2021 Apr 19.
Published in final edited form as: Cell Calcium. 2019 Jan 9;78:56–65. doi: 10.1016/j.ceca.2019.01.003

Fig. 3. CRAC channel function in mast cells.

Fig. 3.

Mast cell Fcε-receptors and GPCR’s such as the cysteinyl leukotriene receptor 1 (CysLTR1) induce calcium entry via store-operated calcium entry (SOCE). Activation of these receptors induces a signaling cascade that activates phospholipase C (PLC) family members, an enzyme that liberates IP3 from membrane bound PIP2. IP3 then releases calcium from the endoplasmic reticulum (ER) through binding to the IP3R. Depletion of ER calcium is sensed by ER resident STIM molecules, STIM1 and STIM2. Calcium-disassociation from the ER luminal EF-hand induces STIM conformational change, oligomerization, binding and opening of the plasma membrane CRAC-channels. This allows sustained calcium entry into the cytoplasm which is important for multiple mast cell functions, including degranulation, leukotriene production and cytokine production.