Modulates calcium-dependent activity of inositol 1,4,5-triphosphate receptors (ITPRs). Inhibits agonist-induced intracellular calcium signaling. Enhances inactivation and does not support calcium-dependent facilitation of voltage-dependent P/Q-type calcium channels. Causes calcium-dependent facilitation and inhibits inactivation of L-type calcium channels by binding to the same sites as calmodulin in the C-terminal domain of CACNA1C, but resulting in an opposit effects on channel function. Suppresses the calcium-dependent inactivation of CACNA1D (By similarity). Inhibits TRPC5 channels. Prevents NMDA receptor-induced cellular degeneration.

Retina and brain. Somatodendritic compartment of neurons. Calbrain was found exclusively in brain where it is abundant in the hippocampus, habenular area in the epithalamus and in the cerebellum.

Contains 4 EF-hand domains.

EF-1 binds magnesium constitutively under physiological conditions, EF-3 and EF-4 bind calcium cooperatively and EF-2 binds neither calcium nor magnesium.

Phosphorylated. The phosphorylation regulates the activity.

Cytoplasm > cell cortex. Cell membrane. S-CaBP1 is localized at or near the plasma membrane; Cytoplasm > cytoskeleton. Cytoplasm > perinuclear region. Cell membrane. Golgi apparatus. Cell junction > synapse > postsynaptic cell membrane > postsynaptic density. L-CaBP1 is associated most likely with the cytoskeletal structures, whereas S-CaBP1 is localized at or near the plasma membrane and Cytoplasm > cytoskeleton. L-CaBP1 is associated most likely with the cytoskeletal structures.