ABCMdb

PMID: 23722250

Kagawa T, Orii R, Hirose S, Arase Y, Shiraishi K, Mizutani A, Tsukamoto H, Mine T
Ursodeoxycholic acid stabilizes the bile salt export pump in the apical membrane in MDCK II cells.
J Gastroenterol. 2014 May;49(5):890-9. doi: 10.1007/s00535-013-0833-y. Epub 2013 May 31., [PubMed]

Sentences

No. Mutations Sentence Comment

11 ABCB11 p.Asp482Gly ABCB11 p.Gly982Arg ABCB11 p.Ala570Thr UDCA significantly increased the activity of Bsep with a benign recurrent intrahepatic cholestasis 2 mutation (A570T) but did not affect Bsep with a progressive familial intrahepatic cholestasis 2 mutation (G982R or D482G). Login to comment 88 ABCB11 p.Asp482Gly ABCB11 p.Gly982Arg ABCB11 p.Ala570Thr MDCK-Ntcp cells were transfected with an expression vector that contained mutated Bsep, including any of a PFIC2 mutation (G982R or D482G) and a BRIC2 mutation (A570T) [11]. Login to comment 90 ABCB11 p.Asp482Gly ABCB11 p.Gly982Arg ABCB11 p.Ala570Thr Basal Bsep activity was slightly lower in the A570T mutant (80.6 % of the wild-type Bsep activity) and much lower in the G982R (15.3 %) and D482G (18.8 %) mutants compared with that in wild-type Bsep (Fig. 6). Login to comment 91 ABCB11 p.Ala570Thr UDCA activated the A570T mutant by 1.3-fold. Login to comment 93 ABCB11 p.Asp482Gly ABCB11 p.Gly982Arg In contrast, UDCA did not affect the activity of the G982R and D482G mutant proteins. Login to comment 163 ABCB11 p.Asp482Gly ABCB11 p.Gly982Arg ABCB11 p.Ala570Thr The inability of TUDCA to stimulate Bsep activity was unexpected because this molecule has been reported to 0 50 100 150 200 wild-type A570T G982R D482G UDCA - + - + - + - + * ** Bsep activity (%) Fig. 6 The effect of UDCA on mutant Bsep activity. Login to comment 164 ABCB11 p.Asp482Gly ABCB11 p.Gly982Arg ABCB11 p.Ala570Thr MDCK II cells stably expressing wild-type or mutant (A570T, G982R, or D482G) Bsep were incubated in the presence or absence of UDCA (100 lM) for 24 h after preincubation with sodium butyrate (5 mM) for 24 h. Thereafter, these cells were incubated for 1 h at 37 &#b0;C with [3 H]-TC (1 lM) and cold TC (10 lM) in the lower compartment. The intracellular accumulation and transcellular flux of TC were calculated on the basis of the radioactivity in the total cells and apical medium, respectively. Bsep activity was determined by the permeability-surface area product for TC transport across the apical membrane (PSapical), which was calculated as (rate of transcellular TC flux)/(intracellular TC concentration). Login to comment 175 ABCB11 p.Asp482Gly ABCB11 p.Gly982Arg Negligible Bsep activity was observed for the G982R and D482G mutants, which cause PFIC2. Login to comment 176 ABCB11 p.Ala570Thr In contrast, the A570T mutant, which causes BRIC2, showed considerable Bsep activity (*70 %), in agreement with a previous report [11]. Login to comment