Imperial College London
Alternate

DrMarkRosenberg

Faculty of Medicine, Department of Metabolism, Digestion and Reproduction

Honorary Research Fellow
 
 
 
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Contact

 

mark.rosenberg

 
 
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Location

 

Sir Alexander Fleming BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Ni:2010:10.1152/ajpcell.00160.2010,
author = {Ni, Z and Bikadi, Z and Cai, X and Rosenberg, MF and Mao, Q},
doi = {10.1152/ajpcell.00160.2010},
journal = {American Journal of Physiology-Cell Physiology},
pages = {C1100--C1109},
title = {Transmembrane helices 1 and 6 of the human breast cancer resistance protein (BCRP/ABCG2): identification of polar residues important for drug transport},
url = {http://dx.doi.org/10.1152/ajpcell.00160.2010},
volume = {299},
year = {2010}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - <jats:p>The human breast cancer resistance protein (BCRP/ABCG2) mediates efflux of drugs and xenobiotics. In this study, we investigated the role of polar residues within or near the predicted transmembrane α-helices 1 and 6 of BCRP in drug transport. We substituted Asn<jats:sup>387</jats:sup>, Gln<jats:sup>398</jats:sup>, Asn<jats:sup>629</jats:sup>, and Thr<jats:sup>642</jats:sup>with Ala, Thr<jats:sup>402</jats:sup>with Ala and Arg, and Tyr<jats:sup>645</jats:sup>with Phe, and the mutants were stably expressed in human embryonic kidney-293 or Flp-In-293 cells. Immunoblotting and confocal microscopy analysis revealed that all of the mutants were well expressed and predominantly targeted to the plasma membrane. While T402A and T402R showed a significant global reduction in the efflux of mitoxantrone, Hoechst 33342, and BODIPY-prazosin, N629A exhibited significantly increased efflux activities for all of the substrates. N387A and Q398A displayed significantly impaired efflux for mitoxantrone and Hoechst 33342, but not for BODIPY-prazosin. In contrast, T642A and Y645F showed a moderate reduction in Hoechst 33342 efflux only. Drug resistance profiles of human embryonic kidney-293 cells expressing the mutants generally correlated with the efflux data. Furthermore, N629A was associated with a marked increase, and N387A and T402A with a significant reduction, in BCRP ATPase activity. Mutations of some of the polar residues may cause conformational changes, as manifested by the altered binding of the 5D3 antibody to BCRP in the presence of prazosin. The inward-facing homology model of BCRP indicated that Thr<jats:sup>402</jats:sup>within transmembrane 1 may be important for helical interactions, and Asn<jats:sup>629</jats:sup>may be involved in BCRP-substrate interaction. In conclusion, we have demonstrated the functional importance of some of these polar residues i
AU  - Ni,Z
AU  - Bikadi,Z
AU  - Cai,X
AU  - Rosenberg,MF
AU  - Mao,Q
DO  - 10.1152/ajpcell.00160.2010
EP  - 1109
PY  - 2010///
SN  - 0363-6143
SP  - 1100
TI  - Transmembrane helices 1 and 6 of the human breast cancer resistance protein (BCRP/ABCG2): identification of polar residues important for drug transport
T2  - American Journal of Physiology-Cell Physiology
UR  - http://dx.doi.org/10.1152/ajpcell.00160.2010
VL  - 299
ER  -
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