Chattopadhyay Subrata, Pearce David A
Center for Aging and Developmental Biology, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA.
Eukaryot Cell. 2002 Aug;1(4):606-12. doi: 10.1128/EC.1.4.606-612.2002.
Btn2p, a novel coiled-coil protein, is up-regulated in btn1delta yeast strains, and this up-regulation is thought to contribute to maintaining a stable vacuolar pH in btn1delta strains (D. A. Pearce, T. Ferea, S. A. Nosel, B. Das, and F. Sherman, Nat. Genet. 22:55-58, 1999). We now report that Btn2p interacts biochemically and functionally with Rsglp, a down-regulator of the Can1p arginine and lysine permease. Rsglp localizes to a distinct structure toward the cell periphery, and strains lacking Btn2p (btn2delta strains) fail to correctly localize Rsg1p. btn2delta strains, like rsg1delta strains, are sensitive for growth in the presence of the arginine analog canavanine. Furthermore, btn2delta strains, like rsg1delta strains, demonstrate an elevated rate of uptake of [14C]arginine, which leads to increased intracellular levels of arginine. Overexpression of BTN2 results in a decreased rate of arginine uptake. Collectively, these results indicate that altered levels of Btn2p can modulate arginine uptake through localization of the Can1p-arginine permease regulatory protein, Rsglp. Our original identification of Btn2p was that it is up-regulated in the btn1delta strain which serves as a model for the lysosomal storage disorder Batten disease. Btnlp is a vacuolar/lysosomal membrane protein, and btn1delta suppresses both the canavanine sensitivity and the elevated rate of uptake of arginine displayed by btn2delta rsg1delta strains. We conclude that Btn2p interacts with Rsglp and modulates arginine uptake. Up-regulation of BTN2 expression in btn1delta strains may facilitate either a direct or indirect effect on intracellular arginine levels.
Btn2p是一种新型的卷曲螺旋蛋白，在btn1δ酵母菌株中上调，这种上调被认为有助于维持btn1δ菌株中稳定的液泡pH值（D.A.皮尔斯、T.费雷亚、S.A.诺塞尔、B.达斯和F.谢尔曼，《自然遗传学》22:55 - 58，1999年）。我们现在报告，Btn2p在生物化学和功能上与Rsglp相互作用，Rsglp是Can1p精氨酸和赖氨酸通透酶的下调因子。Rsglp定位于细胞周边的一个独特结构，而缺乏Btn2p的菌株（btn2δ菌株）无法正确定位Rsg1p。btn2δ菌株与rsg1δ菌株一样，在精氨酸类似物刀豆氨酸存在的情况下对生长敏感。此外，btn2δ菌株与rsg1δ菌株一样，显示出[14C]精氨酸摄取率升高，这导致细胞内精氨酸水平增加。BTN2的过表达导致精氨酸摄取率降低。总的来说，这些结果表明Btn2p水平的改变可以通过Can1p - 精氨酸通透酶调节蛋白Rsglp的定位来调节精氨酸摄取。我们最初鉴定Btn2p是它在btn1δ菌株中上调，该菌株用作溶酶体贮积病巴滕病的模型。Btn1p是一种液泡/溶酶体膜蛋白，btn1δ抑制btn2δrsg1δ菌株显示的刀豆氨酸敏感性和精氨酸摄取率升高。我们得出结论，Btn2p与Rsglp相互作用并调节精氨酸摄取。btn1δ菌株中BTN2表达的上调可能对细胞内精氨酸水平产生直接或间接影响。
