Related Experiment Video
Updated: Jul 28, 2026

Expression, Detergent Solubilization, and Purification of a Membrane Transporter, the MexB Multidrug Resistance Protein
Published on: December 3, 2010
On the putative co-transport of drugs by multidrug resistance proteins
P Borst1, N Zelcer, K van de Wetering
1Center of Biomedical Genetics, Division of Molecular Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands. p.borst@nki.nl
Abstract:
Experiments with multidrug resistance-associated protein 1 (MRP1) showed 10-years ago that transport of vincristine (VCR) by MRP1 could be stimulated by GSH, and transport of GSH by VCR. Since then many examples of stimulated transport have been reported for MRP1, 2, 3, 4 and 8. We discuss here three models to explain stimulated transport. We favour a model in which a large promiscuous binding site can bind more than one ligand, allowing cooperative/competitive interactions between ligands within the binding site. We conclude that there is no unambiguous proof for co-transport of two different ligands by MRPs, but that cross-stimulated transport can explain the published data.
More Related Videos
Related Concept Videos
Membrane Transporters
Transporters are mainly composed of alpha-helices, built from bundles of ten or more helices traversing the plasma membrane. The solute-binding sites are located midway, where some of the helices are broken or distorted, making space for the binding site through...
Drug Absorption Mechanism: Carrier-Mediated Membrane Transport
Facilitated diffusion is a passive process that utilizes human Solute Carrier (SLC) transporters. These transporters bind to the drug, undergo structural...
Cellular Membranes and Drug Transport
Phospholipids arrange themselves into a bilayer, with hydrophilic heads oriented outward and hydrophobic tails facing inward.
Pore Transport and Ion-Pair Transport
Pore transport, also known as convective transport, is a process where small molecules like urea, water, and sugars rapidly cross cell membranes as though there were channels or pores in the membrane. Although direct microscopic evidence is limited but the concept of pores or channels is widely accepted based on physiological evidence. Despite the lack of direct microscopic...
Carrier-Mediated Transport
Active transport involves two types of membrane-spanning transporters: uptake and efflux. Uptake transporters are expressed in the small...
Pharmacogenetics of Drug Transporters: P-Glycoprotein and Solute Carrier Transporters

