Molecular evolution of GPCRs: CRH/CRH receptors.
Corticotrophin-releasing hormone (CRH) is the pivotal neuroendocrine peptide hormone associated with the regulation of the stress response in vertebrates. However, CRH-like peptides are also found in a number of invertebrate species. The origin of this peptide can be traced to a common ancestor of lineages leading to chordates and to arthropods, postulated to occur some 500 million years ago. Evidence indicates the presence of a single CRH-like receptor and a soluble binding protein system that acted to transduce and regulate the actions of the early CRH peptide. In vertebrates, genome duplications led to the divergence of CRH receptors into CRH1 and CRH2 forms in tandem with the development of four paralogous ligand lineages that included CRH; urotensin I/urocortin (Ucn), Ucn2 and Ucn3. In addition, taxon-specific genome duplications led to further local divergences in CRH ligands and receptors. Functionally, the CRH ligand-receptor system evolved initially as a molecular system to integrate early diuresis and nutrient acquisition. As multicellular organisms evolved into more complex forms, this ligand-receptor system became integrated with the organismal stress response to coordinate homoeostatic challenges with internal energy usage. In vertebrates, CRH and the CRH1 receptor became associated with the hypothalamo-pituitary-adrenal/interrenal axis and the initial stress response, whereas the CRH2 receptor was selected to play a greater role in diuresis, nutrient acquisition and the latter aspects of the stress response.
Department of Cell and Systems BiologyUniversity of Toronto, 25 Harbord Street, Toronto, Ontario, Canada L4A IK6Department of Ecology and EvolutionUniversity of Toronto, Toronto, Ontario, CanadaDepartment of Life SciencesUniversity of Toronto Scarborough, Toronto, Ontario, Canada david.lovejoy@utoronto.ca.
David A
DA
Lovejoy
Department of Cell and Systems BiologyUniversity of Toronto, 25 Harbord Street, Toronto, Ontario, Canada L4A IK6Department of Ecology and EvolutionUniversity of Toronto, Toronto, Ontario, CanadaDepartment of Life SciencesUniversity of Toronto Scarborough, Toronto, Ontario, CanadaDepartment of Cell and Systems BiologyUniversity of Toronto, 25 Harbord Street, Toronto, Ontario, Canada L4A IK6Department of Ecology and EvolutionUniversity of Toronto, Toronto, Ontario, CanadaDepartment of Life SciencesUniversity of Toronto Scarborough, Toronto, Ontario, Canada.
Belinda S W
BS
Chang
Department of Cell and Systems BiologyUniversity of Toronto, 25 Harbord Street, Toronto, Ontario, Canada L4A IK6Department of Ecology and EvolutionUniversity of Toronto, Toronto, Ontario, CanadaDepartment of Life SciencesUniversity of Toronto Scarborough, Toronto, Ontario, Canada.
Nathan R
NR
Lovejoy
Department of Cell and Systems BiologyUniversity of Toronto, 25 Harbord Street, Toronto, Ontario, Canada L4A IK6Department of Ecology and EvolutionUniversity of Toronto, Toronto, Ontario, CanadaDepartment of Life SciencesUniversity of Toronto Scarborough, Toronto, Ontario, Canada.
Jon
J
del Castillo
D000311:Adrenal Glands / Q000502:physiology; D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000235:genetics*; D004231:Diuresis; D004734:Energy Metabolism; D019143:Evolution, Molecular; D007031:Hypothalamus / Q000502:physiology; D010902:Pituitary Gland / Q000502:physiology; D018019:Receptors, Corticotropin-Releasing Hormone / Q000235:genetics*; D015398:Signal Transduction; D054832:Urocortins / Q000235:genetics; D014579:Urotensins / Q000235:genetics
D018019:Receptors, Corticotropin-Releasing Hormone; D054832:Urocortins; D014579:Urotensins; D003346:Corticotropin-Releasing Hormone; C029676:urotensin I
CNS; Metazoa; diuresis; energy metabolism; reproduction; stress