Calcyon Neuron Specific Vesicular Protein (CALY)

CALCYON is a type II single transmembrane protein. It is required for maximal stimulated calcium release after stimulation of purinergic or muscarinic but not beta-adrenergic receptors. The encoded protein interacts with D1 dopamine receptor and may interact with other DA receptor subtypes and/or GPCRs. Lezcano et al.identified a cDNA from human brain which they designated calcyon, for 'calcium on,' which encodes a 217-amino acid type II single transmembrane protein. Calcyon has a high degree of sequence similarity to the neuronal proteins p19 and p21. Immunoblot and immunolocalization analyses revealed expression of a 34-kD glycosylated protein in pyramidal neuron dendritic spines in prefrontal cortex and suggested an orientation with extracellular N terminus and cytoplasmic C terminus.