The HeLa cell glucagon-like peptide-2 receptor is coupled to regulation of apoptosis and ERK1/2 activation through divergent signaling pathways.
Glucagon-like peptide-2 (GLP-2) regulates proliferative and cytoprotective pathways in the intestine; however GLP-2 receptor (GLP-2R) signal transduction remains poorly understood, and cell lines that express the endogenous GLP-2R have not yet been isolated. We have now identified several expressed sequence tags from human cervical carcinoma cDNA libraries that correspond to GLP-2R nucleotide sequences. GLP-2R mRNA transcripts were detected by RT-PCR in two human cervical carcinoma cell lines, including HeLa cells. GLP-2 increased cAMP accumulation and activated ERK1/2 in HeLa cells transiently expressing the cloned human HeLa cell GLP-2R cDNA. However, the GLP-2R-induced activation of ERK1/2 was not mediated through Galphas, adenylyl cyclase, or transactivation of the epidermal growth factor receptor, but was pertussis toxin sensitive, inhibited by dominant negative Ras, and dependent on betagamma-subunits. GLP-2 also induced a significant increase in bromodeoxyuridine incorporation that was blocked by dominant negative Ras. Furthermore, GLP-2 inhibited HeLa cell apoptosis induced by LY294002 in a protein kinase A-dependent, but ERK-independent, manner. These findings demonstrate that the HeLa cell GLP-2R differentially signals through both Galphas/cAMP- and Gi/Go-dependent pathways, illustrating for the first time that the GLP-2R is capable of coupling to multiple heterotrimeric G proteins defining distinct GLP-2R-dependent biological actions.
Koehler
J A
JA
Department of Medicine, General Hospital, Banting and Best Diabetes Centre, 200 Elizabeth Street, MBRW4R-402, Toronto, Canada M5G 2C4.
Yusta
B
B
Drucker
D J
DJ
D000262:Adenylyl Cyclases / Q000378:metabolism; D017209:Apoptosis; D015139:Blotting, Southern; D015153:Blotting, Western; D001973:Bromodeoxyuridine / Q000494:pharmacology; D045744:Cell Line, Tumor; D002470:Cell Survival; D002584:Cervix Uteri / Q000378:metabolism; D002867:Chromones / Q000494:pharmacology; D003001:Cloning, Molecular; D000242:Cyclic AMP / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D019281:Dimerization; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066246:ErbB Receptors / Q000378:metabolism; D005260:Female; D015723:Gene Library; D005799:Genes, Dominant; D000067757:Glucagon-Like Peptide-1 Receptor; D006367:HeLa Cells; D006801:Humans; D007150:Immunohistochemistry; D008156:Luciferases / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D008954:Models, Biological; D009025:Morpholines / Q000494:pharmacology; D037342:Pertussis Toxin / Q000494:pharmacology; D010957:Plasmids / Q000378:metabolism; D018027:Receptors, Glucagon / Q000737:chemistry* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D015533:Transcriptional Activation; D014162:Transfection
D002867:Chromones; D018076:DNA, Complementary; D004791:Enzyme Inhibitors; C000593833:GLP1R protein, human; D000067757:Glucagon-Like Peptide-1 Receptor; D009025:Morpholines; D018027:Receptors, Glucagon; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D004247:DNA; D000242:Cyclic AMP; D008156:Luciferases; D037342:Pertussis Toxin; D066246:ErbB Receptors; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D000262:Adenylyl Cyclases; D001973:Bromodeoxyuridine