A novel member of the trehalose transporter family functions as an h(+)-dependent trehalose transporter in the reabsorption of trehalose in malpighian tubules.
A novel member of the trehalose transporter family functions as an h(+)-dependent trehalose transporter in the reabsorption of trehalose in malpighian tubules.
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DOI：
10.3389/fphys.2012.00290
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发表时间：
2012
影响因子：
4
通讯作者：
Kikawada T
中科院分区：
文献类型：
--
作者：
Kikuta S;Hagiwara-Komoda Y;Noda H;Kikawada T
在昆虫中，马氏管在功能上类似于哺乳动物的肾脏，因为它们不仅是将废物分子排泄到管腔中所必需的，而且还负责将不可缺少的分子（例如糖）从管腔重吸收到主细胞。在糖类中，二糖海藻糖对昆虫非常重要，因为它是主要的血淋巴糖，作为能量和碳源。海藻糖转运蛋白TRET 1参与将新合成的海藻糖从脂肪体穿过细胞膜转移到血淋巴中。尽管转运蛋白在马氏管海藻糖的重吸收中起着关键作用，但这一过程的分子背景仍不清楚。以前，我们确定了Tret 1同源物（Nlst 8），主要是在马氏管的褐飞虱（BPH）的表达。在此，我们使用非洲爪蟾卵母细胞表达系统来显示NIST 8发挥在低pH条件下升高的海藻糖转运活性。这些功能测定表明Nlst 8编码质子依赖性海藻糖转运蛋白（H-TRET 1）。为了研究Nlst 8参与海藻糖重吸收，我们通过使用具有RNAi基因沉默的BPH分析了蜜露的糖组成。在高血糖条件下，在蜜露中检测到海藻糖作为从Nlst 8-dsRNA注射的BPH排出的废物。然而，即使在高血糖条件下，海藻糖也不会从注射GFP-dsRNA的BPH中排出。我们的结论是，NlST 8可以参与海藻糖重吸收驱动的H+梯度从管腔的马氏管的主细胞。
In insects, Malpighian tubules are functionally analogous to mammalian kidneys in that they not only are essential to excrete waste molecules into the lumen but also are responsible for the reabsorption of indispensable molecules, such as sugars, from the lumen to the principal cells. Among sugars, the disaccharide trehalose is highly important to insects because it is the main hemolymph sugar to serve as a source of energy and carbon. The trehalose transporter TRET1 participates in the transfer of newly synthesized trehalose from the fat body across the cellular membrane into the hemolymph. Although transport proteins must play a pivotal role in the reabsorption of trehalose in Malpighian tubules, the molecular context underlying this process remains obscure. Previously, we identified a Tret1 homolog (Nlst8) that is expressed principally in the Malpighian tubules of the brown planthopper (BPH). Here, we used the Xenopus oocyte expression system to show that NlST8 exerts trehalose transport activity that is elevated under low pH conditions. These functional assays indicate that Nlst8 encodes a proton-dependent trehalose transporter (H-TRET1). To examine the involvement of Nlst8 in trehalose reabsorption, we analyzed the sugar composition of honeydew by using BPH with RNAi gene silencing. Trehalose was detected in the honeydew as waste excreted from Nlst8-dsRNA-injected BPH under hyperglycemic conditions. However, trehalose was not expelled from GFP-dsRNA-injected BPH even under hyperglycemic conditions. We conclude that NlST8 could participate in trehalose reabsorption driven by a H+ gradient from the lumen to the principal cells of the Malpighian tubules.
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DOI：
10.1111/j.1742-4658.2010.07811.x
发表时间：
2010-10
期刊：
The FEBS journal
影响因子：
--
作者：
Mitsumasu K;Kanamori Y;Fujita M;Iwata K;Tanaka D;Kikuta S;Watanabe M;Cornette R;Okuda T;Kikawada T
通讯作者：
Kikawada T
DOI：
10.1073/pnas.0706197105
发表时间：
2008-04-01
影响因子：
11.1
作者：
Sakurai, Minoru;Furuki, Takao;Okuda, Takashi
通讯作者：
Okuda, Takashi
影响因子：
3.6
作者：
Wood, IS;Trayhurn, P
通讯作者：
Trayhurn, P
影响因子：
2.3
作者：
Jarial, Mohinder S.;Kelly-Worden, Marie
通讯作者：
Kelly-Worden, Marie
影响因子：
1.3
作者：
Moriwaki, N;Matsushita, K;Kono, Y
通讯作者：
Kono, Y