Radiation inactivation suggests that human multidrug resistance-associated protein 1 occurs as a dimer in the human erythrocyte membrane.
Molecular masses of functional units of two components of 2, 4-dinitrophenyl-S-glutathione (DNP-SG) transport across the erythrocyte membrane determined by radiation inactivation were 437 +/- 69 kDa for the high-affinity component and 466 +/- 67 kDa for the low-affinity component. These results confirm that the multidrug resistance-associated protein (MRP) 1 is responsible for the high-affinity DNP-SG transport across the erythrocyte membrane and suggest that MRP1 exists in the membrane as a dimer. The molecular size of the low-affinity transporter is similar if not identical to that of MRP1. Moreover, while the molecular mass of the DNP-SG-ATPase activity of the erythrocyte membrane corresponds also to that of MRP (375 +/- 36 kDa), the molecular mass of the functional unit of dinitrophenol-stimulated ATPase is significantly lower (232 +/- 26 kDa), which suggests that thisactivity is linked to a different protein, perhapsaminophospholipid translocase.
Soszyński
M
M
Department of Molecular Biophysics, University of Lódź, Banacha 12/16, Lódź, 90-237, Poland. sosmirek@krysia.uni.lodz.pl
Kałuzna
A
A
Rychlik
B
B
Sokal
A
A
Bartosz
G
G
D019297:2,4-Dinitrophenol / Q000378:metabolism; D018528:ATP-Binding Cassette Transporters / Q000737:chemistry* / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000328:Adult; D001692:Biological Transport / Q000528:radiation effects; D019281:Dimerization; D004910:Erythrocyte Membrane / Q000737:chemistry* / Q000378:metabolism / Q000528:radiation effects; D005978:Glutathione / Q000031:analogs & derivatives / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D027425:ATP-Binding Cassette, Sub-Family C Proteins
D019297:2,4-Dinitrophenol; D018528:ATP-Binding Cassette Transporters; D000251:Adenosine Triphosphatases; D005978:Glutathione; D027425:ATP-Binding Cassette, Sub-Family C Proteins; C030190:S-(2,4-dinitrophenyl)glutathione