| Background: | Vasoactive Intestinal Polypeptide Receptor 1 (VIPR1) is a member of the Vasoactive Intestinal Polypeptide subfamily. Vasoactive intestinal peptide (VIP) plays multiple roles in the nervous, endocrine, and immune systems as a neurotransmitter, a hormone, and a cytokine. VIPR1, a receptor for VIP, has been shown to expressed widely in normal tissues and is the predominant receptor subtype for VIP in cancers. VIP and its receptors, VIPR1 and VIPR2, are highly expressed in the immune system and modulate diverse T cell functions. Recently VIP-R1 has been shown to be a novel and potent facilitator of HIV-1 infection. Two isoforms are produced by alternative splicing. VIPR1 expression has been documented widely in normal and cancerous tissues, including adipose, adrenal, bladder, blood, brain, breast, colon, ganglion, GI tract, heart, kidney, liver, lung, lymph node, ovary, pancreas, placenta, prostate, skin, small intestine, spinal cord, spleen, stomach, testis, thymus, thyroid, and vessel. ESTs have been isolated from a diverse set of normal and cancerous tissues. |