title: Endothelin-converting enzyme-1 regulates trafficking and signalling of the neurokinin 1 receptor in endosomes of myenteric neurones.
abstract: Neuropeptide signalling at the plasma membrane is terminated by neuropeptide degradation by cell-surface peptidases, and by β-arrestin-dependent receptor desensitization and endocytosis. However, receptors continue to signal from endosomes by β-arrestin-dependent processes, and endosomal sorting mediates recycling and resensitization of plasma membrane signalling. The mechanisms that control signalling and trafficking of receptors in endosomes are poorly defined. We report a major role for endothelin-converting enzyme-1 (ECE-1) in controlling substance P (SP) and the neurokinin 1 receptor (NK(1)R) in endosomes of myenteric neurones. ECE-1 mRNA and protein were expressed by myenteric neurones of rat and mouse intestine. SP (10 nM, 10 min) induced interaction of NK(1)R and β-arrestin at the plasma membrane, and the SP-NK(1)R-β-arrestin signalosome complex trafficked by a dynamin-mediated mechanism to ECE-1-containing early endosomes, where ECE-1 can degrade SP. After 120 min, NK(1)R recycled from endosomes to the plasma membrane. ECE-1 inhibitors (SM-19712, PD-069185) and the vacuolar H(+)ATPase inhibitor bafilomycin A(1), which prevent endosomal SP degradation, suppressed NK(1)R recycling by >50%. Preincubation of neurones with SP (10 nM, 5 min) desensitized Ca(2+) transients to a second SP challenge after 10 min, and SP signals resensitized after 60 min. SM-19712 inhibited NK(1)R resensitization by >90%. ECE-1 inhibitors also caused sustained SP-induced activation of extracellular signal-regulated kinases, consistent with stabilization of the SP-NK(1)R-β-arrestin signalosome. By degrading SP and destabilizing endosomal signalosomes, ECE-1 has a dual role in controlling endocytic signalling and trafficking of the NK(1)R: promoting resensitization of G protein-mediated plasma membrane signalling, and terminating β-arrestin-mediated endosomal signalling.
authors: Department of Surgery, University of California, San Francisco, San Francisco, CA 94143-0660, USA.
authors: Juan-Carlos
authors: JC
authors: Pelayo
authors: Daniel P
authors: DP
authors: Poole
authors: Martin
authors: M
authors: Steinhoff
authors: Graeme S
authors: GS
authors: Cottrell
authors: Nigel W
authors: NW
authors: Bunnett
mesh_terms: D000818:Animals; D019390:Arrestins / Q000378:metabolism; D016282:Aspartic Acid Endopeptidases / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D003106:Colon / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism*; D000072396:Endothelin-Converting Enzymes; D005260:Female; D019204:GTP-Binding Proteins / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D007082:Ileum / Q000378:metabolism; D008297:Male; D008666:Metalloendopeptidases / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D009197:Myenteric Plexus / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018040:Receptors, Neurokinin-1 / Q000378:metabolism*; D015398:Signal Transduction; D013373:Substance P / Q000378:metabolism; D000071557:beta-Arrestins
chemical_list: D019390:Arrestins; D018040:Receptors, Neurokinin-1; D000071557:beta-Arrestins; D013373:Substance P; D016282:Aspartic Acid Endopeptidases; D008666:Metalloendopeptidases; C000606923:ECE1 protein, human; C000606925:Ece1 protein, mouse; D000072396:Endothelin-Converting Enzymes; D019204:GTP-Binding Proteins; D002118:Calcium