dc.contributor.author |
Botha, Rikus |
|
dc.contributor.author |
Kumar, Shree S |
|
dc.contributor.author |
Grimsey, Natasha |
|
dc.contributor.author |
Kay, Emma I |
|
dc.contributor.author |
Mountjoy, Kathleen Grace |
|
dc.date.accessioned |
2022-03-08T22:23:57Z |
|
dc.date.available |
2022-03-08T22:23:57Z |
|
dc.date.issued |
2020-5-8 |
|
dc.identifier.citation |
Journal of the Endocrine Society. 4: A578-A578. 08 May 2020 |
|
dc.identifier.issn |
2472-1972 |
|
dc.identifier.uri |
https://hdl.handle.net/2292/58538 |
|
dc.description.abstract |
<jats:title>Abstract</jats:title>
<jats:p>The human melanocortin 4 receptor (hMC4R) plays a critical role in the regulation of energy balance with more than 150 distinct human obesity-associated mutations. Most exhibit defective MC4R functionality but six have been reported to associate with constitutive activity. This represents a conundrum since a lean phenotype is expected for enhanced MC4R signaling. Human melanocortin 2 receptor accessory protein alpha (hMRAPα) induces hMC4R constitutive activity in transfected HEK293 cells (1,2). We do not know whether the hMRAPα-induced gain-in-function for hMC4R would cause, or prevent, obesity because of this conundrum. Here, we hypothesize that wild-type hMC4R, obesity-associated constitutively active hMC4R and hMRAPα-induced constitutive active hMC4R can exist in distinct conformational states and elicit distinct signaling profiles. To test this, we compared transiently expressed HA-hMC4R in HEK293 cells for basal and agonist activation for adenylyl cyclase, Cre driven β-galactosidase reporter transcription, and receptor protein expression. Six previously reported obesity-associated hMC4R constitutively active variants were compared with two hMC4R constitutively active mutations not associated with obesity, two hMC4R variants associated with protection from development of obesity, five non-constitutively active hMC4R mutations associated with obesity, hMRAPα co-expressed with hMC4R, and wild-type hMC4R. Our data confirm hMC4R constitutive activity coupling to both adenylyl cyclase and Cre β-galactosidase reporter for only two hMC4R variants associated with obesity (H76R & L250Q), one hMC4R mutation (H158R) not associated with obesity, and hMRAPα co-expressed with hMC4R. We show α-MSH stimulated concentration curves for wild-type hMC4R, H76R, L250Q & H158R hMC4R variants and hMRAPα co-expressed with hMC4R coupling to adenylyl cyclase. Surprisingly, out of these, only wild-type hMC4R and H158R hMC4R variant exhibited α-MSH-stimulated Cre β-galactosidase reporter concentration curves. Western blotting and ELISA showed ~70% reduced cell surface and total receptor protein expression for hMC4R co-expressed with hMRAPα and obesity-associated constitutively active hMC4R variants, compared to wild-type hMC4R. To summarize, two constitutively active hMC4R variants (H76R and L250Q) associated with obesity, and hMC4R co-expressed with hMRAPα, share a signaling profile comprising protein expression and α-MSH stimulated functional coupling to adenylyl cyclase and Cre-reporter gene expression. We conclude (1) if hMC4R is co-expressed with hMRAPα in vivo it would likely contribute to human obesity, and (2) obesity-associated constitutively active hMC4R variants exhibit a signaling anomaly that may underpin development of anti-obesity therapeutics.</jats:p>
<jats:p>1. Kay EI, et al. J Mol Endocrinol. 2013;50:203-215.</jats:p>
<jats:p>2. Kay EI, et al. PLoS ONE. 2015;10(10):e0140320.</jats:p> |
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dc.language |
en |
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dc.publisher |
The Endocrine Society |
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dc.relation.ispartofseries |
Journal of the Endocrine Society |
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dc.rights |
Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. |
|
dc.rights.uri |
https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm |
|
dc.rights.uri |
https://creativecommons.org/licenses/by-nc-nd/4.0/ |
|
dc.title |
SAT-598 Shared Signaling Profile Between Human MRAPα-Induced Human MC4R Constitutive Activity and Obesity-Associated Human MC4R Constitutive Activity |
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dc.type |
Journal Article |
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dc.identifier.doi |
10.1210/jendso/bvaa046.1140 |
|
pubs.issue |
Suppl 1 |
|
pubs.begin-page |
sat |
|
pubs.volume |
4 |
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dc.date.updated |
2022-02-16T01:32:20Z |
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dc.rights.holder |
Copyright: Oxford University Press |
en |
pubs.end-page |
598 |
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pubs.publication-status |
Published |
|
dc.rights.accessrights |
http://purl.org/eprint/accessRights/OpenAccess |
en |
pubs.elements-id |
847353 |
|
dc.identifier.eissn |
2472-1972 |
|
pubs.online-publication-date |
2020-5-8 |
|