Environmental control of Pub1 (NEDD4 family E3 ligase) in Schizosaccharomyces pombe is regulated by TORC2 and Gsk3.
Environmental control of Pub1 (NEDD4 family E3 ligase) in Schizosaccharomyces pombe is regulated by TORC2 and Gsk3.
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DOI：
10.26508/lsa.202101082
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发表时间：
2022-05
影响因子：
4.4
通讯作者：
Petersen J
中科院分区：
文献类型：
--
作者：
Wang T;Woodman P;Humphrey SJ;Petersen J
NEDD4家族E3连接酶Pub1受营养环境、TORC 2和Gsk 3信号通路调节，以控制质膜上氨基酸转运蛋白的水平，从而控制营养摄取。细胞通过调节表面营养转运蛋白和受体的丰度来响应不断变化的营养环境。这可以通过调节泛素依赖性内吞作用来实现，其部分由E3连接酶的NEDD4家族调节。在这里，我们报告了新的调节Pub1，裂殖酵母裂殖酵母成员的NEDD4家族的E3连接酶。我们发现，氮胁迫抑制Pub1功能，从而增加了丰富的氨基酸转运蛋白Aat1在质膜和增强敏感性的毒性精氨酸类似物刀豆氨酸。我们发现TOR复合物2（TORC2）信号负调控Pub1，因此营养胁迫下的TORC2突变体降低了质膜上的Aat1，并对刀豆氨酸具有抗性。抑制TORC2信号增加Pub1磷酸化，这取决于Gsk3活性。添加Tor抑制剂Torin 1使Pub1在丝氨酸199（S199）处的磷酸化增加2.5倍，并且S199 A磷酸化缺失突变体中的Pub1蛋白水平降低。S199在NEDD4中是保守的，并且位于蛋白质相互作用所需的WW结构域的上游。总之，我们描述了主要的TORC2营养传感信号网络如何调节Pub1的环境控制，以调节营养转运蛋白的丰度。
The NEDD4 family E3 ligase Pub1 is regulated by the nutrient environment, TORC2, and Gsk3 signalling pathway to control the level of amino acid transporters on the plasma membrane and thus nutrient uptake. Cells respond to changing nutrient environments by adjusting the abundance of surface nutrient transporters and receptors. This can be achieved by modulating ubiquitin-dependent endocytosis, which in part is regulated by the NEDD4 family of E3 ligases. Here we report novel regulation of Pub1, a fission yeast Schizosaccharomyces pombe member of the NEDD4-family of E3 ligases. We show that nitrogen stress inhibits Pub1 function, thereby increasing the abundance of the amino acid transporter Aat1 at the plasma membrane and enhancing sensitivity to the toxic arginine analogue canavanine. We show that TOR complex 2 (TORC2) signalling negatively regulates Pub1, thus TORC2 mutants under nutrient stress have decreased Aat1 at the plasma membrane and are resistant to canavanine. Inhibition of TORC2 signalling increases Pub1 phosphorylation, and this is dependent on Gsk3 activity. Addition of the Tor inhibitor Torin1 increases phosphorylation of Pub1 at serine 199 (S199) by 2.5-fold, and Pub1 protein levels in S199A phospho-ablated mutants are reduced. S199 is conserved in NEDD4 and is located immediately upstream of a WW domain required for protein interaction. Together, we describe how the major TORC2 nutrient-sensing signalling network regulates environmental control of Pub1 to modulate the abundance of nutrient transporters.