| The drug resistant phenotype which develops in various human malignancies has been shown to be associated with the overexpression of a 170 kDa plasma membrane P-glycoprotein. This protein has been shown to increase the efflux of a wide range of cytotoxic drugs from the cell. Although it's thought to function as an energy dependent drug efflux pump, its mechanism of action is not clearly defined. Based on its primary sequence, P-glycoprotein has been identified as a member of a large superfamily of ABC (ATP binding cassette) transport proteins, including many bacterial transporters, and the Cystic Fibrosis Transmembrane conductance Regulator (CFTR). Unlike other members of this family, CFTR functions as a cAMP-dependent chloride (Cl;We have used the Xenopus laevis expression system to study the effects of mdr1 and mdr3 cRNA injection on Cl... |
