ATP-dependent GSH and glutathioneS-conjugate transport in skate liver: role of an Mrp functional homologue

• DOI: 10.1152/ajpgi.2000.279.2.g417
• Publication Date: 2017-12-24T15:26:08Z
• Authors: James F. Rebbeor; Gregory C. Connolly; John H. Henson; James L. Boyer; Nazzareno Ballatori
• Keywords: Skate

Multidrug resistance-associated proteins 1 and 2 (Mrp1 Mrp2) are thought to mediate low-affinity ATP-dependent transport of reduced glutathione (GSH), but there is as yet no direct evidence for this hypothesis. The present study examined whether livers from the little skate ( Raja erinacea) express an Mrp2 homologue liver membrane vesicles exhibit GSH activity. Antibodies directed against mammalian Mrp2-specific epitopes labeled a 180-kDa protein band in plasma membranes stained canaliculi by immunofluorescence, indicating that homologous protein. Functional assays Mrp activity were carried out using 3 H-labeled S-dinitrophenyl-glutathione (DNP-SG). DNP-SG was accumulated both ATP-independent mechanisms. uptake relatively high affinity [Michaelis-Menten constant K m ) = 32 ± 9 μM] cis-inhibited known substrates GSH. Interestingly, S-ethylglutathione also detected vesicles. mediated pathway 12 mM) transporter not affected potential or pH gradient uncouplers. These results provide first support hypothesis efflux cells members family proteins.