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Effects of the gout-causing Q141K polymorphism and a CFTR DeltaF508 mimicking mutation on the processing and stability of the ABCG2 protein.

Sarankó, Hajnalka and Tordai, H. and Telbisz, A. and Laczka, Csilla and Erdos, G. and Sarkadi, Balázs and Hegedűs, Tamás (2013) Effects of the gout-causing Q141K polymorphism and a CFTR DeltaF508 mimicking mutation on the processing and stability of the ABCG2 protein. BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 437 (1). pp. 140-145. ISSN 0006-291X

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Abstract

ABCG2 is an important multidrug transporter involved also in urate transport, thus its mutations can lead to the development of gout and may also alter general drug absorption, distribution and excretion. The frequent ABCG2 polymorphism, Q141K, is associated with an elevated risk of gout and has been controversially reported to reduce the plasma membrane expression and/or the transport function of the protein. In the present work we examined the stability and cellular processing of the Q141K ABCG2 variant, as well as that of the DeltaF142 ABCG2, corresponding to the DeltaF508 mutation in the CFTR (ABCC7) protein, causing cystic fibrosis. The processing and localization of full length ABCG2 variants were investigated in mammalian cells, followed by Western blotting and confocal microscopy, respectively. Folding and stability were examined by limited proteolysis of Sf9 insect cell membranes expressing these ABCG2 constructs. Stability of isolated nucleotide binding domains, expressed in and purified from bacteria, was studied by CD spectroscopy. We find that the Q141K variant has a mild processing defect which can be rescued by low temperature, a slightly reduced activity, and a mild folding defect, especially affecting the NBD. In contrast, the DeltaF142 mutant has major processing and folding defects, and no ATPase function. We suggest that although these mutations are both localized within the NBD, based on molecular modeling their contribution to the ABCG2 structure and function is different, thus rescue strategies may be devised accordingly.

Item Type: Article
Uncontrolled Keywords: TEMPERATURE; Proteolysis/drug effects; Protein Structure, Tertiary; Protein Stability; Protein Processing, Post-Translational; Polymorphism, Single Nucleotide/*genetics; Phenylbutyrates/pharmacology; Neoplasm Proteins/*genetics; Mutation/*genetics; Mutant Proteins/metabolism; Humans; HEK293 Cells; Gout/*genetics; Genetic Predisposition to Disease; Flow Cytometry; Cystic Fibrosis Transmembrane Conductance Regulator/*genetics; Circular Dichroism; Cell Membrane/metabolism; ATP-Binding Cassette Transporters/*genetics
Subjects: Q Science / természettudomány > QH Natural history / természetrajz > QH301 Biology / biológia > QH3011 Biochemistry / biokémia
Q Science / természettudomány > QH Natural history / természetrajz > QH301 Biology / biológia > QH3015 Molecular biology / molekuláris biológia
Q Science / természettudomány > QH Natural history / természetrajz > QH301 Biology / biológia > QH3020 Biophysics / biofizika
SWORD Depositor: MTMT SWORD
Depositing User: MTMT SWORD
Date Deposited: 18 Jan 2014 04:08
Last Modified: 18 Jan 2014 04:08
URI: http://real.mtak.hu/id/eprint/8967

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