Characterization of a novel five-transmembrane domain cholecystokinin-2 receptor splice variant identified in human tumors

► Seven transmembrane domain receptors are targets for diagnosis and therapy of tumors. ► Discrepancy is noticed between mRNA and protein levels of cholecystokinin-2 receptor. ► We cloned a putative five-transmembrane domain receptor from different tumor types. ► Cholecystokinin-2 receptor variant was retained in endoplasmic reticulum. ► It diminished cell surface density and activity of cholecystokinin-2 receptor.