CABP1

Calcium binding proteins are an important component of calcium mediated cellular signal transduction. This gene encodes a protein that belongs to a subfamily of calcium binding proteins which share similarity to calmodulin. The protein encoded by this gene regulates the gating of voltage-gated calcium ion channels. This protein inhibits calcium-dependent inactivation and supports calcium-dependent facilitation of ion channels containing voltage-dependent L-type calcium channel subunit alpha-1C. This protein also regulates calcium-dependent activity of inositol 1,4,5-triphosphate receptors, P/Q-type voltage-gated calcium channels, and transient receptor potential channel TRPC5. This gene is predominantly expressed in retina and brain. Alternative splicing results in multiple transcript variants encoding disinct isoforms.

Full Name

calcium binding protein 1

Function

Modulates calcium-dependent activity of inositol 1,4,5-triphosphate receptors (ITPRs)(PubMed:14570872).
Inhibits agonist-induced intracellular calcium signaling (PubMed:15980432).
Enhances inactivation and does not support calcium-dependent facilitation of voltage-dependent P/Q-type calcium channels (PubMed:11865310).
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 has an opposite effect on channel function (PubMed:15140941).
Suppresses the calcium-dependent inactivation of CACNA1D (By similarity).
Inhibits TRPC5 channels (PubMed:15895247).
Prevents NMDA receptor-induced cellular degeneration. Required for the normal transfer of light signals through the retina (By similarity).

Biological Process

Negative regulation of protein import into nucleus Source: UniProtKB
Response to stimulus Source: UniProtKB-KW
Visual perception Source: UniProtKB

Cellular Location

Golgi apparatus; Cytoskeleton; Cell membrane; Perinuclear region; Postsynaptic density. L-CaBP1 is associated most likely with the cytoskeletal structures, whereas S-CaBP1 is localized at or near the plasma membrane.
Isoform L-CaBP1: Cytoskeleton. L-CaBP1 is associated most likely with the cytoskeletal structures.
Isoform S-CaBP1: Cell membrane; Cell cortex. S-CaBP1 is localized at or near the plasma membrane.

PTM

Phosphorylated. The phosphorylation regulates the activity.