Function: Thought to form a receptor-activated non-selective calcium permeant cation channel. Probably is operated by aphosphatidylinositol second messenger system activated by receptor tyrosine kinases or G-protein coupled receptors. Activated bydiacylglycerol (DAG) in a membrane-delimited fashion, independently of protein kinase C, and by inositol-1,4,5-triphosphatereceptors(ITPR) with bound IP3. May also be activated by internal calcium store depletion Tissue specificity: Abundantly expressed in brain. Concentrated in cerebellar Purkinje cells and sparsely localized in cerebellar granulelyer, pontine nuclei and thalamus. Lower levels detected in other tissues Sequence similarities: Belongs to the transient receptor family. STrpC subfamily. Contains 5 ANK repeats.