Bap29varP, a variant of Bap29, influences the cell surface expression of the human P-glycoprotein

  • Authors:
    • Prema S. Rao
    • Ulrich Bickel
    • Kalkunte S. Srivenugopal
    • U. Subrahmanyeswara Rao
  • View Affiliations

  • Published online on: January 1, 2008     https://doi.org/10.3892/ijo.32.1.135
  • Pages: 135-144
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Abstract

P-glycoprotein (Pgp), a plasma membrane (PM) glycoprotein, is responsible for the development of multidrug resistance. The mechanism by which Pgp is targeted to the PM is not defined. To identify proteins that influence Pgp trafficking, we utilized the yeast two-hybrid analysis procedure, which identified a new isoform of endoplasmic reticulum (ER)-bound Bap29, termed Bap29varP, as an interacting protein with the N-terminus of Pgp. The drug-resistant human breast cancer MCF-7 (MCF-7/AdrR) cells express both Bap29varP and ≈170 kDa Pgp, which are however absent in the drug-sensitive MCF-7 cells. When Bap29varP was overexpressed in MCF-7/AdrR cells, Pgp was predominantly localized in the ER and intracellular vesicles, suggesting Bap29varP influences Pgp trafficking. When Pgp was expressed in MCF-7 cells, it was exclusively found in the ER with a molecular mass of ≈160 kDa slightly smaller than that of the molecular mass of Pgp expressed in MCF-7/AdrR cells. On the other hand, when Pgp was expressed in Bap29varP-containing human colon adenocarcinoma HT-29 cells, it was localized at the PM. These findings together suggest that Bap29varP acts as an essential chaperone, influencing the processing and trafficking of Pgp to the cell surface.

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January 2008
Volume 32 Issue 1

Print ISSN: 1019-6439
Online ISSN:1791-2423

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Spandidos Publications style
Rao PS, Bickel U, Srivenugopal KS and Rao US: Bap29varP, a variant of Bap29, influences the cell surface expression of the human P-glycoprotein. Int J Oncol 32: 135-144, 2008
APA
Rao, P.S., Bickel, U., Srivenugopal, K.S., & Rao, U.S. (2008). Bap29varP, a variant of Bap29, influences the cell surface expression of the human P-glycoprotein. International Journal of Oncology, 32, 135-144. https://doi.org/10.3892/ijo.32.1.135
MLA
Rao, P. S., Bickel, U., Srivenugopal, K. S., Rao, U. S."Bap29varP, a variant of Bap29, influences the cell surface expression of the human P-glycoprotein". International Journal of Oncology 32.1 (2008): 135-144.
Chicago
Rao, P. S., Bickel, U., Srivenugopal, K. S., Rao, U. S."Bap29varP, a variant of Bap29, influences the cell surface expression of the human P-glycoprotein". International Journal of Oncology 32, no. 1 (2008): 135-144. https://doi.org/10.3892/ijo.32.1.135