ABCMdb

PMID: 12223492

Loo TW, Clarke DM
Location of the rhodamine-binding site in the human multidrug resistance P-glycoprotein.
J Biol Chem. 2002 Nov 15;277(46):44332-8. Epub 2002 Sep 9., 2002-11-15 [PubMed]

Sentences

No. Mutations Sentence Comment

130 ABCB1 p.Met68Cys ABCB1 p.Leu65Cys The activity of M68C, was inhibited by 44%, whereas that of mutant L65C was increased (189%). Login to comment 131 ABCB1 p.Tyr118Cys ABCB1 p.Val125Cys Four mutants (Y118C, V125C, V133C, and C137) in TM2 were very sensitive to MTS-rhodamine because they were inhibited 94, 68, 80, and 93%, respectively. Login to comment 132 ABCB1 p.Gln132Cys Mutant Q132C showed weaker inhibition (32%). Login to comment 133 ABCB1 p.Gln195Cys ABCB1 p.Lys189Cys In TM3, the activities of two mutants (K189C and Q195C) were inhibited 76 and 78%, respectively, by MTS-rhodamine. Login to comment 138 ABCB1 p.Asn296Cys ABCB1 p.Phe314Cys In contrast, four mutants (N296C, G300C, Y310C, and F314C) were inhibited by Ͼ70% with MTS-rhodamine. Login to comment 139 ABCB1 p.Ile340Cys ABCB1 p.Ala342Cys The activities of two mutants (I340C and A342C) in TM6 were strongly inhibited (87 and 94%, respectively) by MTS-rhodamine. Login to comment 140 ABCB1 p.Phe343Cys The activity of mutant F343C, however, was increased (347%) after treatment with MTS-rhodamine. Login to comment 155 ABCB1 p.Leu975Cys ABCB1 p.Ile340Cys ABCB1 p.Ala841Cys ABCB1 p.Val982Cys Lower levels of protection were observed with mutants I340C, A841C, L975C, and V982C (Fig. 5). Login to comment 164 ABCB1 p.Leu65Cys ABCB1 p.Phe343Cys Two mutants, L65C and F343C, showed increased activity after treatment with MTS-rhodamine. Login to comment 165 ABCB1 p.Leu65Cys Because mutant L65C had only 51% of the verapamil-stimulated ATPase activity relative to that of the Cys-less parent (22), treatment with MTS treatment essentially restored the activity of the mutant to that of the Cys-less P-gp. Login to comment 167 ABCB1 p.Phe343Cys Mutant F343C showed about 3.5-fold increase in activity after treatment with MTS-rhodamine. Login to comment 168 ABCB1 p.Phe343Cys Because mutant F343C had about 60% of the activity of Cys-less P-gp, reaction with MTS-rhodamine essentially causes a 2-fold increase in activity relative to the Cys-less parent. Login to comment 172 ABCB1 p.Val52Cys ABCB1 p.Gly62Cys Three cysteine mutants (V52C, G54C, and G62C) in TM1 were not tested because of low expression, indicating that these residues must be important for structure and/or function. Login to comment 186 ABCB1 p.Asn839Ile Mutations in TM9 (I837L and N839I) or in TM6 (G388A and A339P) resulted in similar drug resistance profiles with four structurally different drugs (increased resistance to vincristine or actinomycin D but decreased resistance to colchicine or daunorubicin relative to wild-type P-gp). Login to comment