Prasad P D, Wang H, Huang W, Kekuda R, Rajan D P, Leibach F H, Ganapathy V
Department of Obstetrics and Gynecology, Medical College of Georgia, Augusta 30912, USA.
Biochem Biophys Res Commun. 1999 Feb 16;255(2):283-8. doi: 10.1006/bbrc.1999.0206.
We report here on the cloning and functional characterization of human LAT1, a subunit of the amino acid transport system L. The hLAT1 cDNA, obtained from a human placental cDNA library, codes for a protein of 507 amino acids. When functionally expressed in mammalian cells together with the heavy chain of the rat 4F2 antigen (r4F2hc), hLAT1 induces the transport of neutral amino acids. When expressed independently, neither hLAT1 nor r4F2hc was capable of amino acid transport to any significant extent. Thus, the hLAT1-r4F2hc heterodimeric complex is responsible for the observed amino acid transport. The transport process induced by the heterodimer is Na+ independent and is not influenced by pH. It recognizes exclusively neutral amino acids with high affinity. LAT1-specific mRNA is expressed in most human tissues with the notable exception of the intestine.
我们在此报告人LAT1（氨基酸转运系统L的一个亚基）的克隆及功能特性。从人胎盘cDNA文库获得的hLAT1 cDNA编码一个由507个氨基酸组成的蛋白质。当与大鼠4F2抗原重链（r4F2hc）在哺乳动物细胞中共同进行功能性表达时，hLAT1可诱导中性氨基酸的转运。单独表达时，hLAT1和r4F2hc在任何显著程度上均无氨基酸转运能力。因此，hLAT1 - r4F2hc异二聚体复合物负责所观察到的氨基酸转运。该异二聚体诱导的转运过程不依赖于Na + ，且不受pH影响。它仅以高亲和力识别中性氨基酸。LAT1特异性mRNA在大多数人体组织中表达，但肠道是明显的例外。
