Cloning of the dog bile salt export pump (BSEP; ABCB11) and functional comparison with the human and rat proteins.
The dog bile salt export pump (BSEP; ABCB11) was cloned and expressed in a Sf9 insect cell system. The deduced amino acid sequence encodes a 1325-amino-acid protein, which shows 89.4% and 80.2% homology with human BSEP and rat Bsep, respectively. The transcript of the dog Bsep gene was detected at a high level in liver, but not other tissues, by quantitative RT-PCR. The BSEP-expressing membrane vesicles isolated from Sf9 cells exhibited saturable uptake of [(3)H]taurocholic acid with Michaelis constants (K(m)) of 33.7, 22.2 and 19.9 microM for the dog, rat and human transporters, respectively. The uptake of [(3)H]taurocholic acid by all three transporters was significantly inhibited by troglitazone, glibenclamide, and other several inhibitors, while pravastatin inhibited dog Bsep and human BSEP, but not rat Bsep at 100 microM. The IC(50) of troglitazone for dog Bsep, human BSEP, and rat Bsep were 32, 20, and 60 microM, and those of pravastatin were 441, 240 and >1,000 microM, respectively. In conclusion, while dog Bsep shows similar ATP-dependent bile acid transport characteristics to human BSEP and rat Bsep, there is a species difference in affinity for drugs such as pravastatin and troglitazone.
Yabuuchi
Hikaru
H
GenoMembrane, Inc., 75-1 Ono-cho, Tsurumi-ku, Yokohama, 230-0046, Japan. h.yabuuchi@genomembrane.com
Tanaka
Kenji
K
Maeda
Miyako
M
Takemura
Masaaki
M
Oka
Masaki
M
Ohashi
Rikiya
R
Tamai
Ikumi
I
D000074020:ATP Binding Cassette Transporter, Subfamily B, Member 11; D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000502:physiology*; D000595:Amino Acid Sequence; D000818:Animals; D002839:Chromans / Q000494:pharmacology; D003001:Cloning, Molecular; D004285:Dogs; D006801:Humans; D008969:Molecular Sequence Data; D009928:Organ Specificity; D017035:Pravastatin / Q000494:pharmacology; D051381:Rats; D013045:Species Specificity; D018411:Spodoptera; D013656:Taurocholic Acid / Q000378:metabolism; D045162:Thiazolidinediones / Q000494:pharmacology; D000077288:Troglitazone
C093491:ABCB11 protein, human; D000074020:ATP Binding Cassette Transporter, Subfamily B, Member 11; D018528:ATP-Binding Cassette Transporters; C490548:Abcb11 protein, rat; D002839:Chromans; D045162:Thiazolidinediones; D013656:Taurocholic Acid; D000077288:Troglitazone; D017035:Pravastatin