Endothelin-converting enzyme-1 actions determine differential trafficking and signaling of corticotropin-releasing factor receptor 1 at high agonist concentrations.
CRF receptor 1 (CRF(1)), a key neuroendocrine mediator of the stress response, has two known agonists corticotropin-releasing factor (CRF) and urocortin 1 (Ucn1). Here we report that endothelin-converting enzyme-1 (ECE-1) differentially degrades CRF and Ucn1; ECE-1 cleaves Ucn1, but not CRF, at critical residue Arginine-34/35', which is essential for ligand-receptor binding. At near K(D) agonist concentration (30 nm), both Ucn1- and CRF-mediated Ca(2+) mobilization are ECE-1 dependent. Interestingly, at high agonist concentration (100 nm), Ucn1-mediated Ca(2+) mobilization remains ECE-1 dependent, whereas CRF-mediated mobilization becomes independent of ECE-1 activity. At high agonist concentration, ECE-1 inhibition disrupted Ucn1-, but not CRF-induced CRF(1) recycling and resensitization, but did not prolong the association of CRF(1) with β-arrestins. RNA interference-mediated knockdown of Rab suggests that both Ucn1- and CRF-induced CRF(1) resensitization is dependent on activity of Rab11, but not of Rab4. CRF(1) behaves like a class A G protein-coupled receptor with respect to transient β-arrestins interaction. We propose that differential degradation by ECE-1 is a novel mechanism by which CRF(1) receptor is protected from overactivation by physiologically relevant high concentrations of higher affinity ligand to mediate distinct resensitization and downstream signaling.
Department of Surgery, Center for Neurobiology of Digestive Diseases, University of California, San Francisco, San Francisco, California 94143, USA.
Burcu
B
Hasdemir
Shilpi
S
Mahajan
Nigel W
NW
Bunnett
Min
M
Liao
Aditi
A
Bhargava
D000595:Amino Acid Sequence; D000818:Animals; D019390:Arrestins / Q000502:physiology; D016282:Aspartic Acid Endopeptidases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D003346:Corticotropin-Releasing Hormone / Q000502:physiology*; D011992:Endosomes / Q000378:metabolism; D000072396:Endothelin-Converting Enzymes; D057809:HEK293 Cells; D006801:Humans; D008297:Male; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008969:Molecular Sequence Data; D021381:Protein Transport; D059748:Proteolysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D018019:Receptors, Corticotropin-Releasing Hormone / Q000378:metabolism*; D015290:Second Messenger Systems; D013449:Sulfonamides / Q000494:pharmacology; D013453:Sulfonylurea Compounds / Q000494:pharmacology; D022161:Transport Vesicles / Q000378:metabolism; D054832:Urocortins / Q000502:physiology; D000071557:beta-Arrestins; D020691:rab GTP-Binding Proteins / Q000378:metabolism; D020695:rab4 GTP-Binding Proteins / Q000378:metabolism; D000099052:CRF Receptor, Type 1; D000099193:rab11 GTP-Binding Proteins
D019390:Arrestins; D016282:Aspartic Acid Endopeptidases; D003346:Corticotropin-Releasing Hormone; D000072396:Endothelin-Converting Enzymes; D008666:Metalloendopeptidases; D018019:Receptors, Corticotropin-Releasing Hormone; D013449:Sulfonamides; D013453:Sulfonylurea Compounds; D054832:Urocortins; D000071557:beta-Arrestins; D020691:rab GTP-Binding Proteins; D020695:rab4 GTP-Binding Proteins; D000099052:CRF Receptor, Type 1; D000099193:rab11 GTP-Binding Proteins; C419789:SM 19712; C000606923:ECE1 protein, human