Protein kinase C affects the internalization and recycling of organic anion transporting polypeptide 1B1
Protein kinase C affects the internalization and recycling of organic anion transporting polypeptide 1B1
复制标题
蛋白激酶C影响有机阴离子转运多肽1B1的内化和再循环
DOI：
10.1016/j.bbamem.2015.05.011
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发表时间：
2015-10-01
影响因子：
3.4
通讯作者：
Zhou, Chao
中科院分区：
文献类型：
--
作者：
Hong, Mei;Hong, Weifang;Zhou, Chao
有机阴离子转运多肽是溶质载体 (SLC) 家族的成员，也是多种化合物跨膜转运的关键决定因素。 OATP1B1 主要表达于人肝细胞的基底外侧膜，在体内药物清除中发挥重要作用。它已被证明负责多种药物的肝脏摄取。基于计算机的水病分析预测了 OATP 家族成员的氨基和羧基末端以及细胞内环 3 处的几个假定磷酸化位点。因此，它们的转运功能可能受到磷酸化的调节。先前的研究表明，OATP2B1和OATP1A2的摄取功能受蛋白激酶C（PKC）的调节。在本研究中，我们用不同的 PKC 调节剂处理稳定表达 OATP1B1 的 HEK293 细胞，并测量其原型底物 estrone-3-sulfate 的转运活性。研究发现，PKC 激活后 OATP1B1 摄取功能降低。进一步的研究表明，PKC可能通过调节细胞表面蛋白水平来影响OATP1B1活性。此外，我们发现 PKC 激活剂 phorbo112-myristate 13-acetate (PMA) 不仅影响 OATP1B1 的内化，还影响其循环利用。免疫细胞化学分析表明，内化的 OATP1B1 与早期和再循环内体标记物共定位，并且 OATP1B1 与再循环内体的共定位依赖于 PKC 激活。综上所述，我们目前的研究表明 PKC 通过影响转运蛋白的内化和再循环来调节 OATP1B1 的功能。 (C) 2015 Elsevier B.V. 保留所有权利。
Organic anion-transporting polypeptides are members of the solute carrier (SLC) family and key determinants for the transmembrane transport of a wide variety of compounds. OATP1B1 is predominantly expressed at the basolateral membrane of human hepatocytes and play an important role in drug clearance from the body. It has been demonstrated to be responsible for the hepatic uptake of various drugs. Computer-based hydropathy analysis predicted several putative phosphorylation sites at the amino and carboxyl termini and at intracellular loop 3 of OATP family members. Therefore, their transport functions may be regulated by phosphorylation. Previous studies have demonstrated that uptake function of OATP2B1 and OATP1A2 is regulated by protein kinase C (PKC). In the present study, we treated HEK293 cells stably expressing OATP1B1 with different PKC modulators and measured their transport activity for prototypic substrate estrone-3-sulfate. It was found that OATP1B1 uptake function was reduced upon PKC activation. Further studies indicated that PKC may affect OATP1B1 activity through regulation of the cell surface protein level. Moreover, we found out that PKC activator phorbo112-myristate 13-acetate (PMA) not only affects the internalization of OATP1B1 but its recycling as well. Immunocytochemistry analysis revealed that internalized OATP1B1 co-localized with early and recycling endosomal markers and the co-localization of OATP1B1 with recycling endosome is dependent on PKC activation. Taken together, our present study demonstrated that PKC regulates the function of OATP1B1 by affecting internalization and recycling of the transporter protein. (C) 2015 Elsevier B.V. All rights reserved.