Endothelin-converting enzyme-1 actions determine differential trafficking and signaling of corticotropin-releasing factor receptor 1 at high agonist concentrations

Mol Endocrinol. 2012 Apr;26(4):681-95. doi: 10.1210/me.2011-1361. Epub 2012 Feb 9.


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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Arrestins / physiology
  • Aspartic Acid Endopeptidases / antagonists & inhibitors
  • Aspartic Acid Endopeptidases / metabolism*
  • Corticotropin-Releasing Hormone / physiology*
  • Endosomes / metabolism
  • Endothelin-Converting Enzymes
  • HEK293 Cells
  • Humans
  • Male
  • Metalloendopeptidases / antagonists & inhibitors
  • Metalloendopeptidases / metabolism*
  • Molecular Sequence Data
  • Protein Transport
  • Proteolysis
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Corticotropin-Releasing Hormone / metabolism*
  • Second Messenger Systems
  • Sulfonamides / pharmacology
  • Sulfonylurea Compounds / pharmacology
  • Transport Vesicles / metabolism
  • Urocortins / physiology
  • beta-Arrestins
  • rab GTP-Binding Proteins / metabolism
  • rab4 GTP-Binding Proteins / metabolism


  • Arrestins
  • Receptors, Corticotropin-Releasing Hormone
  • SM 19712
  • Sulfonamides
  • Sulfonylurea Compounds
  • Urocortins
  • beta-Arrestins
  • CRF receptor type 1
  • Corticotropin-Releasing Hormone
  • Aspartic Acid Endopeptidases
  • Metalloendopeptidases
  • ECE1 protein, human
  • Endothelin-Converting Enzymes
  • rab11 protein
  • rab GTP-Binding Proteins
  • rab4 GTP-Binding Proteins