Abstract
BackgroundFunctional rescue of misfolded mutant receptors by small non-peptide molecules has been demonstrated. These small, target-specific molecules (pharmacological chaperones or “pharmacoperones”) serve as molecular templates, promote correct folding and allow otherwise misfolded mutants to pass the scrutiny of the cellular quality control system (QCS) and be expressed at the plasma membrane (PM) where they function similarly to wild type (WT) proteins. In the case of the gonadotropin releasing hormone receptor (GnRHR), drugs that rescue one mutant typically rescue many mutants, even if the mutations are located at distant sites (extracellular loops, intracellular loops, transmembrane helices). This increases the value of these drugs. These drugs are typically identified, post hoc, from “hits” in screens designed to detect antagonists or agonists. The therapeutic utility of pharmacoperones has been limited due to the absence of screens that enable identification of pharmacoperones per se.Methods and FindingsWe describe a generalizable primary screening approach for pharmacoperone drugs based on measurement of gain of activity in stable HeLa cells stably expressing the mutants of two different model G-protein coupled receptors (GPCRs) (hGnRHR[E90K] or hV2R[L83Q]). These cells turn off expression of the receptor mutant gene of interest in the presence of tetracycline and its analogs, which provides a convenient means to identify false positives.ConclusionsThe methods described and characterized here provide the basis of novel primary screens for pharmacoperones that detect drugs that rescue GPCR mutants of specific receptors. This approach will identify structures that would have been missed in screens that were designed to select only agonists or antagonists. Non-antagonistic pharmacoperones have a therapeutic advantage since they will not compete for endogenous agonists and may not have to be washed out once rescue has occurred and before activation by endogenous or exogenous agonists.
Highlights
G protein-coupled receptors (GPCRs), which include the gonadotropin releasing hormone (GnRH) receptor (GnRHR) and vasopressin type 2 receptor (V2R), comprise the largest family of validated drug targets; 30–50% of approved drugs derive their benefits by selective targeting of GPCRs [1]
Non-antagonistic pharmacoperones have a therapeutic advantage since they will not compete for endogenous agonists and may not have to be washed out once rescue has occurred and before activation by endogenous or exogenous agonists
When the function of V2R is lost due to mutation, the disease nephrogenic diabetes insipidus (NDI) results
Summary
G protein-coupled receptors (GPCRs), which include the gonadotropin releasing hormone (GnRH) receptor (GnRHR) and vasopressin type 2 receptor (V2R), comprise the largest family of validated drug targets; 30–50% of approved drugs derive their benefits by selective targeting of GPCRs [1]. Functional rescue of misfolded mutant receptors by small non-peptide molecules has been demonstrated These small, target-specific molecules (pharmacological chaperones or ‘‘pharmacoperones’’) serve as molecular templates, promote correct folding and allow otherwise misfolded mutants to pass the scrutiny of the cellular quality control system (QCS) and be expressed at the plasma membrane (PM) where they function to wild type (WT) proteins. In the case of the gonadotropin releasing hormone receptor (GnRHR), drugs that rescue one mutant typically rescue many mutants, even if the mutations are located at distant sites (extracellular loops, intracellular loops, transmembrane helices). This increases the value of these drugs. The therapeutic utility of pharmacoperones has been limited due to the absence of screens that enable identification of pharmacoperones per se
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.