Cholesterol interaction with the daunorubicin binding site of P-glycoprotein.

Journal Article (Journal Article)

The inherent complexities of cholesterol disposition and metabolism preclude a single transmembrane active transport avenue for this steroid-precursor, cell-membrane constituent. Yet the ABC (ATP binding cassette) transporters are inextricably linked to elements of cholesterol disposition. Recent observations have suggested that, under certain settings, the ABC transporter P-glycoprotein (P-gp) performs a direct role in cholesterol disposition. The gene product of MDR1 (multidrug resistance transporter), P-glycoprotein also confers protection against xenobiotics. Using a whole cell assay in which the retention of a marker substrate is evaluated and quantified, we studied the ability of cholesterol to inhibit directly the function of this transporter. In a NIH-G185 cell line presenting an overexpressed amount of the human transporter P-gp, cholesterol caused dramatic inhibition of daunorubicin transport with an IC(50) of about 8 microM yet had no effect on the parent cell line nor rhodamine 123 transport. Additionally, using the ATP-hydrolysis assay, we showed that cholesterol increases P-gp-mediated ATP hydrolysis by approximately 1.6-fold with a K(s) of 5 microM. Suggesting that cholesterol directly interacts with the substrate binding site of P-gp, these results are consistent with cholesterol being transported by MDR1 P-gp.

Full Text

Duke Authors

Cited Authors

  • Wang, E; Casciano, CN; Clement, RP; Johnson, WW

Published Date

  • October 5, 2000

Published In

Volume / Issue

  • 276 / 3

Start / End Page

  • 909 - 916

PubMed ID

  • 11027568

International Standard Serial Number (ISSN)

  • 0006-291X

Digital Object Identifier (DOI)

  • 10.1006/bbrc.2000.3554


  • eng

Conference Location

  • United States