SLC22A2 O15244

溶质载体家族22成员2 (有机阳离子转运蛋白2) (hOCT2)

功能描述

生电性电压依赖性转运蛋白，介导多种有机阳离子的转运，如内源性生物活性胺、阳离子药物和异生物质 (PubMed:9260930, PubMed:9687576)。作为Na(+)-非依赖性、双向单向转运蛋白发挥作用 (PubMed:21128598, PubMed:9687576)。阳离子的细胞摄取或释放由电化学势驱动，即膜电位和浓度梯度 (PubMed:15212162, PubMed:9260930, PubMed:9687576)。然而，当阳离子底物达到饱和浓度时，也可能进行电中性阳离子交换 (By similarity)。主要表达于肝细胞和近端小管的基底侧膜，参与通过肝和肾清除血流中的阳离子化合物的摄取和处置 (PubMed:15783073)。参与单胺类神经递质的摄取，如组胺、多巴胺、肾上腺素、去甲肾上腺素、5-羟色胺和酪胺，从而通过调节神经递质的间质浓度在中枢神经系统中发挥生理作用 (PubMed:16581093, PubMed:17460754, PubMed:9687576)。也能够转运多巴胺能神经调节剂环(组-脯)、salsolinol和N-甲基-salsolinol，从而参与中枢神经系统中多巴胺能细胞完整性的维持 (PubMed:17460754)。介导乙酰胆碱 (ACh) 在气道上皮纤毛细胞顶膜的双向转运，从而在支气管上皮ACh的腔内释放中发挥作用 (PubMed:15817714)。也转运胍和内源性单胺，如维生素B1/硫胺素、肌酐和N-1-甲基烟酰胺 (NMN) (PubMed:12089365, PubMed:15212162, PubMed:17072098, PubMed:24961373, PubMed:9260930)。介导季铵化合物胆碱的摄取和外排 (PubMed:9260930)。介导多胺鲱精胺的双向转运以及多胺腐胺和亚精胺的摄取 (PubMed:12538837, PubMed:21128598)。能够转运非胺类内源性化合物，如前列腺素E2 (PGE2) 和前列腺素F2-alpha (PGF2-alpha) (PubMed:11907186)。也参与异生物质4-(4-(dimethylamino)styryl)-N-methylpyridinium (ASP) 的摄取 (PubMed:12395288, PubMed:16394027)。可能有助于调节睾丸跨血睾屏障的有机化合物转运 (Probable)。 {ECO:0000250|UniProtKB:Q9R0W2, ECO:0000269|PubMed:11907186, ECO:0000269|PubMed:12089365, ECO:0000269|PubMed:12395288, ECO:0000269|PubMed:12538837, ECO:0000269|PubMed:15212162, ECO:0000269|PubMed:15783073, ECO:0000269|PubMed:15817714, ECO:0000269|PubMed:16394027, ECO:0000269|PubMed:16581093, ECO:0000269|PubMed:17072098, ECO:0000269|PubMed:17460754, ECO:0000269|PubMed:21128598, ECO:0000269|PubMed:24961373, ECO:0000269|PubMed:9260930, ECO:0000269|PubMed:9687576, ECO:0000305|PubMed:35307651}.; FUNCTION: [Isoform 2]: 与isoform 1相反，不能转运胍、肌酐、西咪替丁和二甲双胍。 {ECO:0000269|PubMed:12089365, ECO:0000269|PubMed:15212162, ECO:0000269|PubMed:16272756}.

组织特异性

Mainly expressed in kidney, in the cortex and medulla (PubMed:11912245, PubMed:12089365, PubMed:9260930). Localized in testis, mostly to peritubular myoid cells and Leydig cells and also detected along the basal membrane of Sertoli cells (PubMed:12089365, PubMed:35307651). Expressed in brain, in neurons of the cerebral cortex and in various subcortical nuclei (PubMed:12089365, PubMed:9260930, PubMed:9687576). In the brain, also detected in the dopaminergic regions of the substantia nigra (PubMed:17460754). Expressed in tracheal and bronchial ciliated epithelium in the respiratory tract (PubMed:15817714). Also detected in secretory phase endometrium, in scattered stromal cells (PubMed:17393420). Expressed in spleen, placenta, small intestine and spinal cord (PubMed:12089365, PubMed:9260930). Weakly expressed in prostate, uterus and lung (PubMed:12089365).

亚细胞定位

Basolateral cell membrane