Endogenous melanin-concentrating hormone receptor SLC-1 in human melanoma SK-MEL-37 cells.
Melanin-concentrating hormone (MCH) is a hypothalamic neuropeptide that regulates several physiological functions. The orphan G protein-coupled receptors SLC-1 and MCHR2 were recently found to bind MCH with high affinity. We show here that the human melanoma cell line SK-MEL-37 expresses SLC-1 mRNA but not MCHR2 by RT-PCR analysis and immunofluorescence studies. Using Chinese hamster ovary cells and 293 cells overexpressing SLC-1 by cDNA transfection, it was shown that SLC-1 coupled to both G alpha(i)/G alpha(o) and G alpha(q) proteins. In SK-MEL-37 cells, MCH inhibited forskolin-stimulated cyclic AMP accumulation and induced mitogen-activated protein kinase (MAPK) in a pertussis toxin-(PTX)-sensitive manner. The MAPK activity leads to the production of phosphorylated forms of p42/p44 MAPK. However, an increase in the intracellular free Ca(2+) concentration was not elicited by MCH in SK-MEL-37 cells. These results show that SLC-1 is coupled only to PTX-sensitive G alpha(i)/G alpha(o) in SK-MEL-37 cells. This study provides for the first time a skin-derived cellular model to analyze the molecular mechanism of the MCH signaling pathway.
Saito
Y
Y
Department of Pharmacology, Saitama Medical School, Morohongo, Saitama 350-0495, Japan. yumisait@saitama-med.ac.jp
Wang
Z
Z
Hagino-Yamagishi
K
K
Civelli
O
O
Kawashima
S
S
Maruyama
K
K
D000818:Animals; D016466:CHO Cells; D005576:Colforsin / Q000494:pharmacology; D006224:Cricetinae; D000242:Cyclic AMP / Q000378:metabolism; D004790:Enzyme Induction / Q000187:drug effects; D020962:Heterotrimeric GTP-Binding Proteins / Q000378:metabolism; D006801:Humans; D007028:Hypothalamic Hormones / Q000378:metabolism* / Q000494:pharmacology; D008543:Melanins / Q000378:metabolism* / Q000494:pharmacology; D008545:Melanoma / Q000235:genetics / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000096:biosynthesis; D008954:Models, Biological; D037342:Pertussis Toxin; D010766:Phosphorylation; D010907:Pituitary Hormones / Q000378:metabolism* / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D011979:Receptors, Pituitary Hormone / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D014407:Tumor Cells, Cultured; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D007028:Hypothalamic Hormones; D008543:Melanins; D010907:Pituitary Hormones; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D011979:Receptors, Pituitary Hormone; D010566:Virulence Factors, Bordetella; C092274:melanin-concentrating hormone receptor; D005576:Colforsin; C019463:melanin-concentrating hormone; D000242:Cyclic AMP; D037342:Pertussis Toxin; D020928:Mitogen-Activated Protein Kinases; D020962:Heterotrimeric GTP-Binding Proteins