IP3R2: a multi-pass endoplasmic reticulum membrane receptor for inositol 1,4,5-trisphosphate, a second messenger that mediates the release of intracellular calcium. This release is regulated by cAMP both dependently and independently of PKA. Most normal tissues displayed weak to moderate cytoplasmic positivity. Strong staining was observed in the gastrointestinal tract, hepatocytes and exocrine pancreas. Short isoform Is found in skeletal muscle and heart. The receptor contains a calcium channel in its C-terminal extremity. Its large N-terminal cytoplasmic region has the ligand-binding site in the N-terminus and modulatory sites in the middle portion immediately upstream of the channel region. Phosphorylation by PKA increases calcium release. Calcium appears to inhibit ligand binding to the receptor, most probably by interacting with a distinct calcium-binding protein which then inhibits the receptor. Belongs to the InsP3 receptor family. 2 isoforms of the human protein are produced by alternative splicing. The short isoform is found in skeletal muscle and heart.
Protein type: Membrane protein, multi-pass; Channel, calcium; Membrane protein, integral; Channel, ligand-gated
Chromosomal Location of Human Ortholog: 12p11
Cellular Component: endoplasmic reticulum membrane; sarcoplasmic reticulum membrane; membrane; plasma membrane; integral to membrane; cell cortex; receptor complex
Molecular Function: calcium ion transmembrane transporter activity; phosphoinositide binding; inositol 1,4,5-triphosphate-sensitive calcium-release channel activity
Biological Process: epidermal growth factor receptor signaling pathway; platelet activation; inositol phosphate-mediated signaling; fibroblast growth factor receptor signaling pathway; nerve growth factor receptor signaling pathway; signal transduction; transport; phospholipase C activation; response to hypoxia; energy reserve metabolic process; innate immune response; blood coagulation; vascular endothelial growth factor receptor signaling pathway; regulation of insulin secretion
Disease: Anhidrosis, Isolated, With Normal Sweat Glands
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