Mackenzie Bryan, Erickson Jeffrey D
Membrane Biology Program and Renal Division, Brigham and Women's Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA.
Pflugers Arch. 2004 Feb;447(5):784-95. doi: 10.1007/s00424-003-1117-9. Epub 2003 Jul 4.
The sodium-coupled neutral amino acid transporters (SNAT) of the SLC38 gene family resemble the classically-described System A and System N transport activities in terms of their functional properties and patterns of regulation. Transport of small, aliphatic amino acids by System A subtypes (SNAT1, SNAT2, and SNAT4) is rheogenic and pH sensitive. The System N subtypes SNAT3 and SNAT5 also countertransport H(+), which may be key to their operation in reverse, and have narrower substrate profiles than do the System A subtypes. Glutamine emerges as a favored substrate throughout the family, except for SNAT4. The SLC38 transporters undoubtedly play many physiological roles including the transfer of glutamine from astrocyte to neuron in the CNS, ammonia detoxification and gluconeogenesis in the liver, and the renal response to acidosis. Probing their regulation has revealed additional roles, and recent work has considered SLC38 transporters as therapeutic targets in neoplasia.
SLC38基因家族的钠偶联中性氨基酸转运体（SNAT）在功能特性和调节模式方面类似于经典描述的A系统和N系统转运活性。A系统亚型（SNAT1、SNAT2和SNAT4）对小的脂肪族氨基酸的转运是生电的且对pH敏感。N系统亚型SNAT3和SNAT5也反向转运H⁺，这可能是它们反向运作的关键，并且其底物谱比A系统亚型更窄。除了SNAT4外，谷氨酰胺是整个家族中较受青睐的底物。SLC38转运体无疑发挥着许多生理作用，包括在中枢神经系统中谷氨酰胺从星形胶质细胞向神经元的转运、肝脏中的氨解毒和糖异生以及肾脏对酸中毒的反应。对其调节的研究揭示了其他作用，并且最近的研究将SLC38转运体视为肿瘤形成中的治疗靶点。
