Human vasoactive intestinal peptide1 receptors expressed by stable transfectants couple to two distinct signaling pathways.
Vasoactive intestinal peptide (VIP) is a potent neuropeptide mediator of central and peripheral nervous system function. A human VIP1 receptor (HVR) cDNA clone was previously obtained from HT29 intestinal epithelial cells and lung tissue. Stably-transfected human embryonic kidney 293 cells and chinese hamster ovary (CHO) cells expressing about 10(6) HVRs per cell that bind [125I]VIP with a Kd of 0.2-0.8 nM, and specifically recognized by anti-HVR antibodies, were established and characterized. VIP induced increases in intracellular cAMP levels ([cAMP]i) dose-dependently with an EC50 of 0.2 nM in 293 and CHO stable transfectants and concurrently evoked dose-dependent increases in intracellular calcium concentrations ([Ca2+]i), as determined by fluorescence-dye spectroscopy. Untransfected 293 and CHO cells showed minimal binding or intracellular effects of VIP; however, native VIP1 receptors of HT29 cells also increased [cAMP]i and [Ca2+]i in dose-dependent responses to VIP. Thus recombinant and native human VIP1 receptors both couple to two distinct signal transduction pathways within a single cell type.
Sreedharan
S P
SP
Department of Medicine, University of California, San Francisco 94143-0711.
Patel
D R
DR
Xia
M
M
Ichikawa
S
S
Goetzl
E J
EJ
D000818:Animals; D016466:CHO Cells; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D003001:Cloning, Molecular; D006224:Cricetinae; D000242:Cyclic AMP / Q000378:metabolism*; D004622:Embryo, Mammalian; D004848:Epithelium; D006801:Humans; D007422:Intestines; D007668:Kidney; D007700:Kinetics; D008168:Lung; D018005:Receptors, Vasoactive Intestinal Peptide / Q000096:biosynthesis* / Q000378:metabolism; D015398:Signal Transduction; D014162:Transfection; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism / Q000494:pharmacology*
D018005:Receptors, Vasoactive Intestinal Peptide; D014660:Vasoactive Intestinal Peptide; D000242:Cyclic AMP; D002118:Calcium