Deletion of the gene encoding the multidrug efflux pump Pdr5 sensitizes cells to puromycin. The andrastins inhibit proteins involved in the efflux of anticancer drugs from multidrug-resistant cancer cells. This antimicrobial resistance is thought to be attributable mainly to multidrug efflux pumps. Some types of efflux pumps can act to decrease intracellular quinolone concentration. These interactions result in a synergistic increase in auxin efflux. P-gp is an ATP-dependent drug efflux pump for xenobiotic compounds with broad substrate specificity. The efflux of potassium ions decreases the membrane potential or hyperpolarizes the cell. This is mediated through MRP-1 dependent efflux. Specialized potassium efflux channels participate in mediating release of potassium from guard cells. Auxin relies on PIN1 which works as an auxin efflux carrier. Drug resistance associated with drug efflux, mediated by P-glycoprotein, was originally reported in mammalian cells. Calcium dependent efflux of the osmolyte Taurine. Resting platelets maintain active calcium efflux via a cyclic AMP-activated calcium pump. Mutations in drug efflux pumps have also been linked to resistance. The presence of these molecules causes a production of ROS and K+ efflux.