A role for P-glycoprotein in regulating cell death

P-glycoprotein (P-gp) is an energy dependent drug pump responsible for mult idrug resistance (MDR) in human cancers. While it is irrefutable that P-gp can efflux xenobiotics out of cells, the biological function of P-gp in mul ticellular organisms has yet to be firmly established. The question of what , if anything, P-gp does when nor effluxing drugs has been raised by recent reports indicating that P-gp may regulate apoptosis, chloride channel acti vity, cholesterol metabolism and immune cell function. There is now a livel y debate regarding the possible role of P-gp in regulating cell differentia tion, proliferation and survival.