Indirect regulation of the intestinal H+-coupled amino acid transporter hPAT1 (SLC36A1)
Indirect regulation of the intestinal H+-coupled amino acid transporter hPAT1 (SLC36A1)
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DOI：
10.1002/jcp.20337
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发表时间：
2005-08-01
影响因子：
5.6
通讯作者：
Thwaites, DT
中科院分区：
文献类型：
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作者：
Anderson, CMH;Thwaites, DT
AH（+）偶联氨基酸转运蛋白在人肠细胞系Caco-2的刷状缘膜上进行了功能表征。这种载体hPAT1 （human质子偶联氨基酸转运蛋白1）或SLC36A1最近在分子水平上被发现，hPAT1蛋白定位于人小肠的刷状边界膜。hPAT1运输氨基酸（例如，β -丙氨酸）和治疗剂（例如，d -环丝氨酸）。在人Caco-2细胞中，hPAT1功能（H+/氨基酸同调）与细胞内pH（pH(i)）的降低有关，pH(i)选择性地激活Na+/H+交换剂NHE3，从而维持pHi和hPAT1功能的驱动力（H+电化学梯度）。本研究为hPAT1功能调控提供了第一个证据。使用药理学工具（forskolin, 8-br-cAMP, [(11,22,28)Ala]VIP）或生理激活剂（神经肽VIP和PACAP）激活Caco-2细胞单层中的cAMP/蛋白激酶A通路，可抑制顶端膜上的hPAT1功能（β -丙氨酸摄取）。在NHE3无活性的条件下（缺乏Na+，顶端pH为5.5，存在NHE3抑制剂S1611），没有观察到β -丙氨酸摄取的调节。Forskolin和VIP抑制β -丙氨酸诱导的细胞内酸化中pHi的恢复（NHE3功能）。免疫细胞化学将NHERF1 （NHE3调节因子1）定位到cco -2细胞的顶端，在那里它将与NHE3相互作用，并允许pka介导的NHE3磷酸化。总之，我们已经证明通过hPAT1的氨基酸摄取被cAMP途径的激活剂通过抑制NHE3活性间接抑制。j .细胞。中国生物医学工程学报，2016,33(4):557 - 557。(c) 2005 Wiley-Liss, Inc。
AH(+)-coupled amino acid transporter has been characterised functionally at the brush border membrane of the human intestinal cell line Caco-2. This carrier, hPAT1 (human Proton-coupled Amino acid Transporter 1) or SLC36A1, has been identified recently at the molecular level and hPAT1 protein is localised to the brush border membrane of human small intestine. hPAT1 transports both amino acids (e.g., beta-alanine) and therapeutic agents (e.g., D-Cycloserine). In human Caco-2 cells, hPAT1 function (H+/amino acid symport) is associated with a decrease in intracellular pH (pH(i)), which selectively activates the Na+/H+ exchanger NHE3, and thus maintains pHi and the driving force for hPAT1 function (the H+ electrochemical gradient). This study provides the first evidence for regulation of hPAT1 function. Activation of the cAMP/protein kinase A pathway in Caco-2 cell monolayers either using pharmacological tools (forskolin, 8-br-cAMP, [(11,22,28)Ala]VIP) or physiological activators (the neuropeptides VIP and PACAP) inhibited hPAT1 function (beta-alanine uptake) at the apical membrane. Under conditions where NHE3 is inactive (the absence of Na+, apical pH 5.5, the presence of the NHE3 inhibitor S1611) no regulation of beta-alanine uptake is observed. Forskolin and VIP inhibit pHi recovery (NHE3 function) from beta-alanine-induced intracellular acidification. Immunocytochemistry localises NHERF1 (NHE3 regulatory factor 1) to the apical portion of Caco-2 cells where it will interact with NHE3 and allow PKA-mediated phosphorylation of NHE3. In conclusion, we have shown that amino acid uptake via hPAT1 is inhibited by activators of the cAMP pathway indirectly through inhibition of NHE3 activity. J. Cell. Physiol. 204: 604-613, 2005. (c) 2005 Wiley-Liss, Inc.