Functional role of arginine 375 in transmembrane helix 6 of multidrug resistance protein 4 (MRP4/ABCC4)

Autor: Frans G. M. Russel, Azza A.K. El-Sheikh, Jan B. Koenderink, Jeroen J. M. W. van den Heuvel, Elmar Krieger
Rok vydání: 2008
Předmět:
Models
Molecular
DNA
Complementary
Arginine
Guanosine Monophosphate
Membrane transport and intracellular motility [NCMLS 5]
Synthetic Organic Chemistry
Biology
Kidney
Protein Structure
Secondary
Cell Line
Cell membrane
Serine
Metabolism
transport and motion [NCMLS 2]
Protein structure
medicine
Humans
Fluorescent Antibody Technique
Indirect
Renal disorder [IGMD 9]
Pharmacology
chemistry.chemical_classification
Alanine
Binding Sites
Dose-Response Relationship
Drug
Multidrug resistance-associated protein 2
Cell Membrane
Poverty-related infectious diseases [N4i 3]
Biological Transport
Molecular biology
Cellular Structures
Protein Structure
Tertiary
Amino acid
Pathogenesis and modulation of inflammation [N4i 1]
Renal disorders [UMCN 5.4]
Kinetics
Transmembrane domain
Methotrexate
medicine.anatomical_structure
Amino Acid Substitution
Biochemistry
chemistry
Growth and differentiation [NCMLS 3]
CGMP transport
Molecular Medicine
Multidrug Resistance-Associated Proteins
Baculoviridae
Protein Binding
Zdroj: Molecular Pharmacology, 74, 4, pp. 964-971
Molecular Pharmacology, 74, 964-971
ISSN: 0026-895X
Popis: Contains fulltext : 70256.pdf (Publisher’s version ) (Open Access) Multidrug resistance protein (MRP) 4 transports a variety of endogenous and xenobiotic organic anions. MRP4 is widely expressed in the body and specifically localized to the renal apical proximal tubule cell membrane, where it mediates the excretion of these compounds into urine. To characterize the MRP4 substrate-binding site, the amino acids Phe368, Phe369, Glu374, Arg375, and Glu378 of transmembrane helix 6, and Arg998 of helix 12, localized in the intracellular half of the central pore, were mutated into the corresponding amino acids of MRP1 and MRP2. Membrane vesicles isolated from human embryonic kidney 293 cells overexpressing these mutants showed significantly reduced methotrexate (MTX) and cGMP transport activity compared with vesicles that expressed wild-type MRP4. The only exception was substitution of Arg375 with serine, which had no effect on cGMP transport but significantly decreased the affinity of MTX. Substitution of the same amino acid with a positively charged lysine returned the MTX affinity to that of the wild type. Furthermore, MTX inhibition of MRP4-mediated cGMP transport was noncompetitive, and the inhibition constant was increased by introduction of the R375S mutation. A homology model of MRP4 showed that Arg375 and Arg998 face right into the central aqueous pore of MRP4. We conclude that positively charged amino acids in transmembrane helices 6 and 12 contribute to the MRP4 substrate-binding pocket. 8 p.
Databáze: OpenAIRE
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