Ward, Natalie-Anne and Hirst, Simon and Williams, John and Findlay, John B. C.
(2012)
Pharmacological chaperones increase the
cell-surface expression of intracellularly retained
mutants of the melanocortin 4 receptor with
unique rescuing efficacy profiles.
Biochemical Society Transactions, 40.
pp. 717-720.
ISSN 0300-5127
Abstract
Mutated versions of membrane proteins often fail to express at the plasma membrane, but instead are
trapped in the secretory pathway, resulting in disease. The retention of these mutant proteins is thought
to result from local misfolding, which prevents export from the ER (endoplasmic reticulum), targeting
the receptor for degradation via the ER-associated quality control system. The rhodopsin-like G-proteincoupled
MC4R (melanocortin 4 receptor) is an example of such a membrane protein. Over 100 natural MC4R
mutations are linked with an obese phenotype and to date represent the most common monogenic cause
of severe early-onset obesity. More than 80% of these mutations result in a substantial proportion of MC4R
being retained intracellularly. If these receptors were expressed at the plasma membrane, many could
be functional, as mutations often occur in regions distinct from those associated with ligand or G-protein
binding. Our aim is to show proof of concept that selective compounds can rescue the function of MC4R
mutants by increasing their cell-surface expression, and further to this, examine whether the rescue profile
differs between mutants. Whole-cell ELISA and 96-well fluorescence-based assays with N-terminally HA
(haemagglutinin)-tagged and C-terminally mCherry-tagged mutant MC4Rs were used to screen a number of
novel MC4R-selective compounds. A total of four related compounds increased the cell-surface expression
of wild-type and three intracellularly retained mutant MC4Rs, thus acting as pharmacological chaperones.
There appears to be a unique rescue efficacy profile for each compound that does not correlate with potency,
suggesting distinct receptor conformations induced by the different mutations. A degree of functionality of
V50M and S58C was also rescued following relocation to the cell surface.
| Item Type: |
Article
|
| Additional Information: |
This paper was presented at the Protein Folding and Misfolding: Mechanisms and Consequences;
Irish Area Section Annual Meeting 2011, 1-2 December 2011, Glenroyal Hotel/National University of Ireland Maynooth |
| Keywords: |
cell-surface rescue; intracellular retention; melanocortin 4 receptor (MC4R);
pharmacological chaperone; rescue efficacy profile; |
| Academic Unit: |
Faculty of Science and Engineering > Biology |
| Item ID: |
5993 |
| Identification Number: |
https://doi.org/10.1042/BST20110764 |
| Depositing User: |
Professor John Findlay
|
| Date Deposited: |
31 Mar 2015 14:47 |
| Journal or Publication Title: |
Biochemical Society Transactions |
| Publisher: |
Portland Press |
| Refereed: |
Yes |
| URI: |
|
| Use Licence: |
This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available
here |
Repository Staff Only(login required)
 |
Item control page |
Downloads per month over past year
Origin of downloads
Altmetric
Altmetric