Homology between P-glycoprotein and a bacterial haemolysin transport protein suggests a model for multidrug resistance

摘要: Increased expression of P-glycoprotein, a plasma membrane glycoprotein relative molecular mass (Mr) 170,000 (170K), occurs in wide variety cell lines that exhibit pleiotropic resistance to unrelated drugs1–4. The presence P-glycoprotein human cancers refractory chemotherapy suggests tumour cells with multidrug can arise during malignant progression5. We have discovered striking homology between and the HlyB protein, 66K Eschericia coli protein required for export haemolysin (protein Mr 107K). be viewed as tandem duplication protein. hydropathy profiles two proteins are similar reveal an extensive transmembrane region resembling those found pore-forming proteins. C-terminal contain sequences homologous nucleotide-binding domains group closely related bacterial ATP-binding propose model which functions energy-dependent pump reduce intracellular levels anticancer drugs.