ABCB4 p.Asp459His
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PMID: 24594635
[PubMed]
Gordo-Gilart R et al: "Functional analysis of ABCB4 mutations relates clinical outcomes of progressive familial intrahepatic cholestasis type 3 to the degree of MDR3 floppase activity."
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9
Results Eight distinct ABCB4 mutations were identified: one nonsense, one splicing and six missense mutations, four of which (G68R, T201M, P479L, D459H) affected MDR3 expression level.
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ABCB4 p.Asp459His 24594635:9:146
status: NEW10 G68R and D459H also led to retention of the protein in endoplasmic reticulum.
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ABCB4 p.Asp459His 24594635:10:9
status: NEW42 Plasmids and site-directed mutagenesis The plasmid pReceiver-M02-MDR3, containing the full open reading frame of ABCB4 (Capital Biosciences, Rockville, Maryland, USA) was used as a template for introducing the substitutions G68R, T201M, P352L, D459H, S978P and E1118K, by site-directed mutagenesis using the QuickChange II system (Agilent Technologies, Santa Clara, California, USA).
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ABCB4 p.Asp459His 24594635:42:244
status: NEW111 By contrast, mutations G68R and D459H resulted in intracellular retention of the protein, with predominant localisation in the endoplasmic reticulum (ER), as revealed by colocalisation with the ER marker calnexin (figure 2).
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ABCB4 p.Asp459His 24594635:111:32
status: NEW117 MDR3 was detected as a 140-150 kDa band, Table 2 ABCB4 mutations and MDR3 immunohistochemical analysis Mutation allele 1 Mutation allele 2 Patient n Nucleotide change Predicted effect Nucleotide change Predicted effect MDR3 staining 1 c.3559C>T p.R1187X c.3633+2 T>A Splicing defect ABSENT 2 c.202G>A p.G68R c.202G>A p.G68R ABSENT 3 c.202G>A p.G68R c.202G>A p.G68R NA 4 c.1375G>C p.D459H c.1436C>T p.P479L FAINT 5 c.602C>T p.T201M c.3352G>A p.E1118K NORMAL 6 c.2932T>C p.S978P ND NORMAL Immunostaining was carried out on liver biopsy specimens in patients 2-6 and in hepatectomy specimens in patient 1.
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ABCB4 p.Asp459His 24594635:117:382
status: NEW122 (C) Faint staining in patient 4, who is compound heterozygous for two missense mutations (D459H and P479L).
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ABCB4 p.Asp459His 24594635:122:90
status: NEW128 By contrast, expression levels of mutants G68R and D459H were markedly decreased (15% and 20% of wild-type, respectively), consistent with the fact that ER retention usually leads to a premature degradation of the proteins.32 T201M and P479L mutations also caused a significant reduction in the expression of MDR3 (60% and 65% of wild-type, respectively).
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ABCB4 p.Asp459His 24594635:128:51
status: NEW142 The same pattern was obtained with mutants G68R and D459H (data not shown), consistent with their absence of expression at the plasma membrane.
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ABCB4 p.Asp459His 24594635:142:52
status: NEW158 We found that changes G68R and D459H caused a marked reduction in MDR3 expression with an accompanying retention of the protein in the ER.
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ABCB4 p.Asp459His 24594635:158:31
status: NEW