1. Structural basis of prostaglandin efflux by MRP4
- Author
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Pourmal, Sergei, Green, Evan, Bajaj, Ruchika, Chemmama, Ilan E, Knudsen, Giselle M, Gupta, Meghna, Sali, Andrej, Cheng, Yifan, Craik, Charles S, Kroetz, Deanna L, and Stroud, Robert M
- Subjects
Biochemistry and Cell Biology ,Chemical Sciences ,Biological Sciences ,Prostaglandins ,Multidrug Resistance-Associated Proteins ,Biological Transport ,Dinoprostone ,Membrane Transport Proteins ,Medical and Health Sciences ,Biophysics ,Developmental Biology ,Biological sciences ,Biomedical and clinical sciences ,Chemical sciences - Abstract
Multidrug resistance protein 4 (MRP4) is a broadly expressed ATP-binding cassette transporter that is unique among the MRP subfamily for transporting prostanoids, a group of signaling molecules derived from unsaturated fatty acids. To better understand the basis of the substrate selectivity of MRP4, we used cryogenic-electron microscopy to determine six structures of nanodisc-reconstituted MRP4 at various stages throughout its transport cycle. Substrate-bound structures of MRP4 in complex with PGE1, PGE2 and the sulfonated-sterol DHEA-S reveal a common binding site that accommodates a diverse set of organic anions and suggest an allosteric mechanism for substrate-induced enhancement of MRP4 ATPase activity. Our structure of a catalytically compromised MRP4 mutant bound to ATP-Mg2+ is outward-occluded, a conformation previously unobserved in the MRP subfamily and consistent with an alternating-access transport mechanism. Our study provides insights into the endogenous function of this versatile efflux transporter and establishes a basis for MRP4-targeted drug design.
- Published
- 2024