ATP-dependent transport of bile salts by rat multidrug resistance-associated protein 3 (Mrp3)
ATP-dependent transport of bile salts by rat multidrug resistance-associated protein 3 (Mrp3)
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DOI：
10.1074/jbc.275.4.2905
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发表时间：
2000-01-28
影响因子：
4.8
通讯作者：
Sugiyama, Y
中科院分区：
文献类型：
--
作者：
Hirohashi, T;Suzuki, H;Sugiyama, Y
我们先前已经证明，克隆的大鼠多药耐药相关蛋白3(MRP3)具有转运有机阴离子的能力，如17β-雌二醇17-β-D-葡萄糖醛酸苷(E(2)17βG)，并具有不同于MRP1和MRP2的底物特异性，因为谷胱甘肽结合物是MRP3(Hirohashi，T，Suzuki，H.和Sugiyama，Y，(1999)J，Biol)的不良底物。化学。274、15181-15185)。[H-3]牛磺胆酸(TC)、[C-14]甘胆酸(GC)、[H-3]牛磺鹅脱氧胆酸-3-硫酸酯(TCDC-S)和[H-3]牛磺胆酸-3-硫酸盐(TLC-S)的摄取受到明显的刺激。MRP3介导的胆盐转运程度依次为：TLC-S>；TCDC-S>；TC>；GC。吸收TC和TLC-S的K-m和V-max分别为：K-m=15.9+/-4.9µM和V-max=50.1+/-9.3pmoL/min/mg蛋白质和K-m=3.06+/-0.57u M和V-max=161.9+/-21.7pmol/min/mg蛋白质。在55 nm[H-3]E(2)17βG和1.2µM[H-3]TC下，ATP的表观K-m值分别为1.36和0.66 mm。在所考察的胆盐中，S对[H-3]E(2)17βG和[H-3]TC的转运有相同程度的抑制作用，其IC50与10 mU M相近。在所考察的胆盐中，S对[H-3]E(2)17βG和[H-3]TC的摄取抑制作用最强(IC50接近1 mU M)，而胆酸盐对[H-3]E(2)17βG和[H-3]TC摄取的抑制作用较弱(IC50类似于75 mU M)。虽然TC和GC是由胆盐输出泵/P-糖蛋白姊妹转运的，但不是由MRP2转运的，TCDC-S和TLC-S是由MRP2转运的，但不是由胆盐输出泵/P-糖蛋白姊妹转运的。
We have previously shown that cloned rat multidrug resistance-associated protein 3 (Mrp3) has the ability to transport organic anions such as 17 beta-estradiol 17-beta-D-glucuronide (E(2)17 beta G) and has a different substrate specificity from MRP1 and MRP2 in that glutathione conjugates are poor substrates for Mrp3 (Hirohashi, T,, Suzuki, H., and Sugiyama, Y, (1999) J, Biol. Chem. 274, 15181-15185). In the present study, the involvement of Mrp3 in the transport of endogenous bile salts was investigated using membrane vesicles from LLC-PK1 cells transfected with rat Mrp3 cDNA The ATP-dependent uptake of [H-3]taurocholate (TC), [C-14]glycocholate (GC), [H-3]taurochenodeoxycholate-3-sulfate (TCDC-S), and [H-3]taurolithocholate-3-sulfate (TLC-S) was markedly stimulated by Mrp3 transfection in LLC-PK1 cells. The extent of Mrp3-mediated transport of bile salts was in the order, TLC-S > TCDC-S > TC > GC. The K-m and V-max values for the uptake of TC and TLC-S were K-m = 15.9 +/- 4.9 mu M and V-max = 50.1 +/- 9.3 pmol/min/mg of protein and K-m = 3.06 +/- 0.57 mu M and V-max = 161.9 +/- 21.7 pmol/min/mg of protein, respectively. At 55 nM [H-3]E(2)17 beta G and 1.2 mu M [H-3]TC, the apparent K-m values for ATP were 1.36 and 0.66 mM, respectively, TC, GC, and TCDC-S inhibited the transport of [H-3]E(2)17 beta G and [H-3]TC to the same extent with an apparent IC50 of similar to 10 mu M. TLC-S inhibited the uptake of [H-3]E(2)17 beta G and [H-3]TC most potently (IC50 of similar to 1 mu M) among the bile salts examined, whereas cholate weakly inhibited the uptake (IC50 similar to 75 mu M). Although TC and GC are transported by bile salt export pump/sister of P-glycoprotein, but not by MRP2, and TCDC-S and TLC-S are transported by MRP2, but not by bile salt export pump/sister of P-glycoprotein, it was found that Mrp3 accepts all these bile salts as substrates, This information, together with the finding that MRP3 is extensively expressed on the basolateral membrane of human cholangiocytes, suggests that MRP3/Mrp3 plays a significant role in the cholehepatic circulation of bile salts.