Views on the co-evolution of the melanocortin-2 receptor, MRAPs, and the hypothalamus/pituitary/adrenal-interrenal axis
•The evolution of the HPA-I axis is intertwined with the co-evolution of the MRAPs and MC2R.•The putative HPI axis in cartilaginous fishes appears to be MRAP independent.•The MC2R ortholog in the HPA-I axis of teleost and tetrapods is MRAP dependent.•The transition to a MRAP dependent HPI axis occur...
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Published in | Molecular and cellular endocrinology Vol. 408; pp. 12 - 22 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
Ireland
Elsevier Ireland Ltd
15.06.2015
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Subjects | |
Online Access | Get full text |
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Summary: | •The evolution of the HPA-I axis is intertwined with the co-evolution of the MRAPs and MC2R.•The putative HPI axis in cartilaginous fishes appears to be MRAP independent.•The MC2R ortholog in the HPA-I axis of teleost and tetrapods is MRAP dependent.•The transition to a MRAP dependent HPI axis occurred in the ancestral bony fishes.
A critical regulatory component of the hypothalamus/pituitary/adrenal axis (HPA) in mammals, reptiles and birds, and in the hypothalamus/pituitary/interrenal (HPI) axis of amphibians and teleosts (modern bony fishes) is the strict ligand selectivity of the melanocortin-2 receptor (MC2R). Tetrapod and teleost MC2R orthologs can only be activated by the anterior pituitary hormone, ACTH, but not by any of the MSH-sized ligands coded in POMC. In addition, both tetrapod and teleost MC2R orthologs require co-expression with the accessory protein, MRAP. However, the MC2R ortholog of the elephant shark, a cartilaginous fish, can be activated by either ACTH or the MSH-sized ligands, and the elephant shark MC2R ortholog does not require co-expression with an MRAP for activation. Given these observations, this review will provide a scenario for the co-evolution of MC2R and MRAP, based on the assumption that the obligate interaction between MC2R and MRAP evolved during the early radiation of the ancestral bony fishes. |
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Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-3 content type line 23 ObjectType-Review-1 |
ISSN: | 0303-7207 1872-8057 |
DOI: | 10.1016/j.mce.2014.12.022 |