Calcium binding protein 1 is a protein that in humans is encoded by the CABP1 gene. Calcium-binding protein 1 is a calcium-binding protein discovered in 1999. It has two EF hand motifs and is expressed in neuronal cells in such areas as hippocampus, habenular nucleus of the epithalamus, Purkinje cell layer of the cerebellum, and the amacrine cells and cone bipolar cells of the retina. Calcium-binding protein 1 which is a neuron -specific member of the calmodulin (CaM) superfamily which modulates Ca2+-dependent activity of inositol trisphosphate receptors (InsP3RS). L-CaBP1 is also associated with the cytoskeleton structures. But the S-CaBP1 is situated in or near the plasma membrane. In brain, CaBp1 is found in the cerebral cortex and hippocampus and in the protein, Cabp1 is found in cone bipolar and amacrine cells. We can also express that CaBP1 may regulate Ca2+ dependent activity of InSP3Rs by promoting structural contacts between suppressor and core domains but has no effect on INsP3 binding to the receptor. CaBP1 contains four EF-hands in two separate domains namely, EF1 and Ef2 is contained in N-domain whereas Ef3 and EF4 is contained in c domain to which Ca2+ binds.[7] Calcium-binding protein 1 (CaBP1) is placed in the lumen of the endoplasmic reticulum.it is relocated outside cells during apoptosis and involved in the phagocytosis of apoptotic cells. CaBP1 and CaM. lobes fold independently. CaBP1-CaM chimeras based on exchange of three elements these are N-lobe, C-lobe and inter lobe linker. Expression of CaBP1 helps to block Ca2+-dependent facilitation of P/Q-type Ca2+ current which is markedly reduced facilitation of synaptic transmission.