SLC17A5 Q9NRA2

唾液酸转运蛋白 (H(+)/硝酸根协同转运蛋白) (H(+)/唾液酸协同转运蛋白) (AST) (膜糖蛋白 HP59) (溶质载体家族17成员5) (囊泡兴奋性氨基酸转运蛋白) (VEAT)

功能描述

多功能阴离子转运蛋白，通过两种不同的转运机制运作，即质子偶联阴离子共转运和膜电位依赖性阴离子转运 (PubMed:15510212, PubMed:21781115, PubMed:22778404, PubMed:23889254)。电中性质子偶联酸性单糖同向转运蛋白，糖与质子的化学计量比为1:1。在向外指向的溶酶体pH梯度的驱动下，将源自唾液酸糖复合物降解的葡萄糖醛酸和游离唾液酸转运出溶酶体。可能调节溶酶体功能和唾液酸化复合物的代谢，从而影响中枢神经系统中少突胶质细胞谱系分化和髓鞘形成 (By similarity) (PubMed:15510212, PubMed:21781115, PubMed:22778404, PubMed:23889254)。生电性质子偶联硝酸根同向转运蛋白，跨唾液腺腺泡细胞基底侧膜转运硝酸根离子，硝酸根与质子的化学计量比为2:1。可能通过唾液腺促进血清中硝酸根的清除，并在唾液腺中进一步浓缩后分泌到唾液中 (PubMed:22778404)。利用膜电位驱动酸性氨基酸和多肽摄取进入突触囊泡。负责松果体细胞中L-天冬氨酸和L-谷氨酸的突触囊泡储存，以及N-乙酰-L-天冬氨酰-L-谷氨酸神经肽的囊泡摄取，这与天冬氨酸相关的谷氨酸能神经传递以及抑制后续递质释放的代谢型受体激活有关 (By similarity) (PubMed:21781115, PubMed:22778404, PubMed:23889254)。 {ECO:0000250|UniProtKB:Q5Q0U0, ECO:0000250|UniProtKB:Q8BN82, ECO:0000269|PubMed:15510212, ECO:0000269|PubMed:21781115, ECO:0000269|PubMed:22778404, ECO:0000269|PubMed:23889254}.; FUNCTION: CM101的受体，CM101是由B群链球菌产生的具有抗病理性血管生成特性的多糖。 {ECO:0000250|UniProtKB:Q9MZD1}.

组织特异性

In the adult, detected in placenta, kidney and pancreas. Abundant in the endothelial cells of tumors from ovary, colon, breast and lung, but is not detected in endothelial cells from the corresponding normal tissues (PubMed:10581036, PubMed:11751519). Highly expressed in salivary glands and liver, with lower levels of expression in brain, spleen kidney, muscle and pancreas. Expressed in acinar cells of salivary glands (at protein level) (PubMed:22778404).

亚细胞定位

Basolateral cell membrane