STIMULATION OF SYSTEM Y+-LIKE AMINO-ACID-TRANSPORT BY THE HEAVY-CHAIN OF HUMAN 4F2 SURFACE-ANTIGEN IN XENOPUS-LAEVIS OOCYTES
STIMULATION OF SYSTEM Y+-LIKE AMINO-ACID-TRANSPORT BY THE HEAVY-CHAIN OF HUMAN 4F2 SURFACE-ANTIGEN IN XENOPUS-LAEVIS OOCYTES
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DOI：
10.1073/pnas.89.12.5606
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发表时间：
1992-06-15
影响因子：
11.1
通讯作者：
MURER, H
中科院分区：
文献类型：
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作者：
BERTRAN, J;MAGAGNIN, S;MURER, H
最近分离出肾皮质 cDNA 克隆 (rBAT)，其在体外转录和加帽互补 RNA (cRNA) 并注射到非洲爪蟾卵母细胞中后，诱导了类似 b0,+ 系统的氨基酸转运活性。该 cDNA 编码一种 II 型膜糖蛋白，与另一种 II 型膜糖蛋白（人和小鼠 4F2 表面抗原 (4F2hc) 的重链）具有显着的同源性。在这里，我们证明，将人 4F2hc cRNA 注射到卵母细胞中会导致阳离子偏好氨基酸转运系统的激活，该系统似乎与卵母细胞中已经存在的 y+ 样转运相同。这是基于以下结果：(i) 将 4F2hc cDNA (4F2hc cRNA) 的体外转录物注射到卵母细胞中，可刺激 L-精氨酸的钠依赖性摄取高达 10 倍，以及 L-亮氨酸的钠依赖性摄取高达 4.1 倍。相反，4F2hc cRNA 不会增加 L-亮氨酸的基础钠依赖性摄取。 (ii) 在钠存在的情况下，基础和 4F2hc cRNA 刺激的不依赖钠的 L-精氨酸吸收完全被 L-亮氨酸抑制。同样，L-亮氨酸的基础和 4F2hc cRNA 刺激的钠依赖性摄取完全被 L-精氨酸抑制。 (iii)通过注射4F2hc cRNA诱导的L-精氨酸的钠依赖性摄取的刺激和L-亮氨酸的钠依赖性摄取的刺激均被二元L氨基酸完全抑制，并且在较小程度上被D-鸟氨酸抑制。 (iv) 基础和 4F2hc cRNA 刺激的不依赖于钠的 L-精氨酸摄取均显示出系统 y+ 转运活性的两个附加特征：仅在钠存在的情况下抑制 L-高丝氨酸的 L-精氨酸摄取，以及随着细胞外 pH 值降低，L-组氨酸施加的抑制增加。我们的结果使我们能够提出，另一个 II 型膜糖蛋白家族（由 rBAT 和 4F2hc 组成）参与氨基酸转运，或者作为特异性激活剂，或者作为氨基酸转运系统的组成部分。
A kidney cortex cDNA clone (rBAT) has recently been isolated, which upon in vitro transcription and capping complementary RNA (cRNA) and injection into Xenopus laevis oocytes induces a system b0,+-like amino acid transport activity. This cDNA encodes a type II membrane glycoprotein that shows significant homology to another type II membrane glycoprotein, the heavy chain of the human and mouse 4F2 surface antigen (4F2hc). Here we demonstrate that injection of human 4F2hc cRNA into oocytes results in the activation of a cation-preferring amino acid transport system that appears to be identical to the y+-like transport already present in the oocyte. This is based on the following results: (i) Injection of in vitro transcripts from 4F2hc cDNA (4F2hc cRNA) into oocytes stimulates up to 10-fold the sodium-independent uptake of L-arginine and up to 4.1-fold the sodium-dependent uptake of L-leucine. In contrast, 4F2hc cRNA does not increase the basal sodium-independent uptake of L-leucine. (ii) Basal and 4F2hc cRNA-stimulated sodium-independent uptake of L-arginine is completely inhibited by L-leucine in the presence of sodium. Similarly, the basal and 4F2hc cRNA-stimulated sodium-dependent uptake of L-leucine is entirely inhibited by L-arginine. (iii) The stimulation of sodium-independent uptake of L-arginine and the stimulation of sodium-dependent uptake of L-leucine induced by injection of 4F2hc cRNA are both completely inhibited by dibasic L amino acids and to a lesser extent by D-ornithine. (iv) Both basal and 4F2hc cRNA-stimulated sodium-independent uptake of L-arginine show two additional characteristics of the system y+ transport activity: inhibition of L-arginine uptake by L-homoserine only in the presence of sodium and an increase in the inhibition exerted by L-histidine as the extracellular pH decreased. Our results allow us to propose that an additional family of type II membrane glycoproteins (composed by rBAT and 4F2hc) is involved in amino acid transport, either as specific activators or as components of amino acid transport systems.