Hippocalcin (HPCA)

HPCA is a member of neuron-specific calcium-binding proteins family found in the retina and brain. This protein is associated with the plasma membrane. It has similarities to proteins located in the photoreceptor cells that regulate photosignal transduction in a calcium-sensitive manner. This protein displays recoverin activity and a calcium-dependent inhibition of rhodopsin kinase. It is identical to the rat and mouse hippocalcin proteins and thought to play an important role in neurons of the central nervous system in a number of species.The primary structure of rat hippocalcin comprises 193 amino acid residues and shows striking sequence similarities to proteins located in the photoreceptor cells that regulate photosignal transduction in a Ca(2+)-sensitive manner. Hippocalcin is associated with the plasma membrane.