ABCMdb

ABCB1 p.Asp164Cys

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Publications

PMID: 24064216 [PubMed] Kapoor K et al: "Mutations in intracellular loops 1 and 3 lead to misfolding of human P-glycoprotein (ABCB1) that can be rescued by cyclosporine A, which reduces its association with chaperone Hsp70."

No. Sentence Comment

7 It was observed that the D164C/D805C mutant, when expressed in HeLa cells, led to misprocessing of P-gp, which thus failed to transport the drug substrates. Login to comment
29 2 The abbreviations used are: ABC, ATP binding cassette; P-gp, P-glycoprotein; CsA, cyclosporine A; CYH, cycloheximide; ER, endoplasmic reticulum; ICL, intracellular loop; NBD, nucleotide binding domain; NBD-CsA, NBD-cyclosporine A; Rh123, rhodamine 123; SNP, single-nucleotide polymorphism; TMD, transmembrane domain; Endo H, endo-beta-N-acetylgluco- saminidase H; PNGase F, peptide N-glycosidase F; FKBP, FK506-binding protein; DD, D164C/D805C. Login to comment
35 Our insect cell studies show that the double mutant D164C/D805C displays no change in Km for ATP binding, thus contradicting the suggested direct interaction of these residues with ATP (5). Login to comment
37 The conserved aspartates, when mutated to cysteine singly (D164C, D805C) or together (D164C/D805C), affected the processing and trafficking of P-gp to the cell membrane. Login to comment
38 We discovered that the maturation defect associated with the D164C/D805C mutant was sensitive to growth temperature. Login to comment
39 When cells expressing the D164C/ D805C mutant were incubated at 27 &#b0;C (similar to growth conditions for High-five insect cells), normal maturation of P-gp was observed. Login to comment
41 Subsequently, we observed that the incubation of cells expressing the D164C/ D805C mutant in the presence of pharmacological chaperones or substrates such as cyclosporine A (CsA) completely rescued the misfolded protein as a functional protein to the cell surface. Login to comment
416 Lane 1, cysless-WT; lane 2, D164C/D805C; lane 3, cysless-WT (CsA); lane 4, D164C/D805C (CsA). Login to comment
424 Importantly, like èc;F508-CFTR (43), once the D164C/D805C mutant P-gp is rescued and reaches the cell surface, it is functional to the same levels as cysless-WT. Login to comment

PMID: 25987565 [PubMed] Loo TW et al: "The Transmission Interfaces Contribute Asymmetrically to the Assembly and Activity of Human P-glycoprotein."

No. Sentence Comment

289 To test if residues Asp-164 or Asp-805 were essential for activity, Kapoor et al. (51) tested the effects of introducing D164C or D805C mutations into human Cys-less P-gp. Login to comment
291 The D164C mutation reduced cell surface expression to about 40% of the Cys-less parent while the presence of both the D164C and D805C mutations reduced cell surface expression to about 20% of the parent. Login to comment
292 Immunoblot analysis of whole cell extracts expressing D164C/D805C showed that the major product was immature P-gp. Login to comment
293 The observation that P-gp mutants R262A/ R905A, T263A/T906A (this study), and D164C/D805C (51) retain substantial activity suggests that there are multiple NBD-TMD contacts as reported by Jin et al. (21). Login to comment
294 The D164C/D805C mutant could be efficiently rescued when expressed in the presence of cyclosporine A to yield mature P-gp as the major product. Login to comment
299 The likely explanation is that the D164C mutation was introduced into a Cys-less P-gp background while the D164A mutation was introduced into a wild-type background. Login to comment