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Updated: Feb 28, 2026
Author Spotlight: A Bicelle Crystallization Setup for ABC Transporter Membrane Proteins to Advance Drug Development
Published on: August 25, 2023
Folding correction of ABC-transporter ABCB1 by pharmacological chaperones: a mechanistic concept
Matthias Spork1, Muhammad Imran Sohail1,2, Diethart Schmid3
1Institute of Medical Chemistry Center of Pathobiochemistry and Genetics Medical University of Vienna Waehringerstrasse 10 Vienna A-1090 Austria.
Abstract:
Point mutations of ATP-binding cassette (ABC) proteins are a common cause of human diseases. Available crystal structures indicate a similarity in the architecture of several members of this protein family. Their molecular architecture makes these proteins vulnerable to mutation, when critical structural elements are affected. The latter preferentially involve the two transmembrane domain (TMD)/nucleotide-binding domain (NBD) interfaces (transmission interfaces), formation of which requires engagement of coupling helices of intracellular loops with NBDs. Both, formation of the active sites and engagement of the coupling helices, are contingent on correct positioning of ICLs 2 and 4 and thus an important prerequisite for proper folding. Here, we show that active site compounds are capable of rescuing P-glycoprotein (P-gp) mutants ∆Y490 and ∆Y1133 in a concentration-dependent manner. These trafficking deficient mutations are located at the transmission interface in pseudosymmetric position to each other. In addition, the ability of propafenone analogs to correct folding correlates with their ability to inhibit transport of model substrates. This finding indicates that folding correction and transport inhibition by propafenone analogs are brought about by binding to the active sites. Furthermore, this study demonstrates an asymmetry in folding correction with cis-flupentixol, which reflects the asymmetric binding properties of this modulator to P-gp. Our results suggest a mechanistic model for corrector action in a model ABC transporter based on insights into the molecular architecture of these transporters.
Insights
Point mutations in ATP-binding cassette (ABC) proteins cause disease. This study shows that active site compounds can rescue P-glycoprotein (P-gp) mutants, suggesting a new therapeutic approach for ABC transporter-related disorders.
Area of Science:
- Biochemistry
- Molecular Biology
- Structural Biology
Background:
- Point mutations in ATP-binding cassette (ABC) proteins are a significant cause of human diseases.
- The molecular architecture of ABC transporters, particularly the transmembrane domain (TMD)/nucleotide-binding domain (NBD) interfaces, renders them susceptible to disease-causing mutations.
- Proper folding and function depend on the correct positioning of intracellular loops (ICLs) and the formation of active sites.
Purpose of the Study:
- To investigate the potential of active site compounds to rescue specific P-glycoprotein (P-gp) mutants.
- To explore the relationship between folding correction, transport inhibition, and drug binding sites in ABC transporters.
- To elucidate the mechanistic model of corrector action in ABC transporters.
Main Methods:
- Utilized P-glycoprotein (P-gp) mutants (∆Y490 and ∆Y1133) located at the transmission interface.
- Assessed the concentration-dependent rescue effects of active site compounds on P-gp mutants.
- Examined the correlation between folding correction and transport inhibition by propafenone analogs.
- Investigated asymmetric folding correction using cis-flupentixol.
Main Results:
- Active site compounds demonstrated a concentration-dependent ability to rescue P-gp mutants ∆Y490 and ∆Y1133.
- Propafenone analogs corrected folding and inhibited transport, indicating binding to the active site.
- Observed asymmetric folding correction with cis-flupentixol, reflecting its asymmetric binding properties.
- A mechanistic model for corrector action in ABC transporters was proposed.
Conclusions:
- Active site compounds can effectively rescue specific P-gp mutants, offering potential therapeutic strategies.
- Folding correction and transport inhibition by certain analogs are mediated by active site binding.
- The study highlights the importance of molecular architecture in ABC transporter function and mutation effects.
- Results provide insights into the mechanism of corrector action for ABC transporter-related diseases.
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