Acts as a calcium sensor for mitochondrial flash (mitoflash) activation, an event characterized by stochastic bursts of superoxide production (By similarity). May play a role in neuronal differentiation (PubMed:16336229). Widely expressed (PubMed:16336229). Highest expression in testis, followed by ovary, kidney, cerebrum, cerebellum, heart, liver, and spleen (PubMed:12270117). In the cerebrum and cerebellum, undetectable at embryonic stages, expression increases after birth up to adult stage (PubMed:12270117). In adult CNS, detected in neurons of the cerebellum, cerebrum and hippocampus formation, including dentate gyrus and Cornu Ammonis, but not in the white matter (PubMed:12270117). In the testis, expressed in spermatocytes, but not in spermatogonia nor in interstitial cells (PubMed:12270117). In ovary, found predominantly in mural granulosa cells and those of the cumulus oophorus (PubMed:12270117). In kidney, expressed in collecting ducts, but not in glomeruli (PubMed:12270117). Not detected in skeletal muscle (PubMed:12270117). In the cerebral cortex, at birth, confined in the Purkinje cell layer (PCL) and in cerebellar nuclei. Not detected in the external germinal layer (EGL). At P5 and P10, predominantly found in the PCL and internal germinal layer (IGL). Not detected in the EGL. At P10 and P20, up-regulated. At P20, expression similar to that of the adult cerebellum.