Phosphorylation of the novel mTOR substrate Unkempt regulates cellular morphogenesis.
Phosphorylation of the novel mTOR substrate Unkempt regulates cellular morphogenesis.
复制标题
DOI：
10.1016/j.jbc.2022.102788
复制
发表时间：
2023-01
影响因子：
4.8
通讯作者：
Bateman, Joseph M.
中科院分区：
文献类型：
--
作者：
Baskaran, Pranetha;Mihaylov, Simeon R.;Vinsland, Elin;Shah, Kriti;Granat, Lucy;Ultanir, Sila K.;Tee, Andrew R.;Murn, Jernej;Bateman, Joseph M.
雷帕霉素的机制靶点（mTOR）是一种整合多种输入来调节合成代谢细胞过程的蛋白激酶。例如，mTOR复合物1 （mTORC1）在生长控制、自噬和代谢中具有关键功能。然而，对于mTORC1下游调控细胞形态发生的信号成分知之甚少。在这里，我们发现rna结合蛋白Unkempt是细胞形态发生的关键调节因子，是mTORC1的一种新的底物。我们发现Unkempt磷酸化通过mTORC1受到营养水平和生长因子的调节。为了分析Unkempt的磷酸化，我们在存在或不存在mTORC1抑制剂雷帕霉素的情况下免疫沉淀细胞中的Unkempt，并使用质谱法鉴定mTORC1依赖性磷酸化残基。该分析表明，mtorc1依赖性磷酸化集中在Unkempt的c端一半富含丝氨酸的内在无序区。我们还发现Unkempt与mTORC1物理相互作用，并通过结合mTOR的调控相关蛋白Raptor直接被mTORC1磷酸化。此外，对缺乏TSC1表达的小鼠发育中的大脑的分析表明，Unkempt的磷酸化在体内依赖于mTORC1。最后，对富丝氨酸区关键丝氨酸/苏氨酸残基的突变分析表明，磷酸化抑制了Unkempt诱导双极形态的能力。因此，这个富含丝氨酸的区域内的磷酸化深刻地影响了Unkempt调节细胞形态发生的能力。综上所述，我们的发现揭示了mTORC1信号传导和细胞形态发生之间的一种新的分子联系。
Mechanistic target of rapamycin (mTOR) is a protein kinase that integrates multiple inputs to regulate anabolic cellular processes. For example, mTOR complex 1 (mTORC1) has key functions in growth control, autophagy, and metabolism. However, much less is known about the signaling components that act downstream of mTORC1 to regulate cellular morphogenesis. Here, we show that the RNA-binding protein Unkempt, a key regulator of cellular morphogenesis, is a novel substrate of mTORC1. We show that Unkempt phosphorylation is regulated by nutrient levels and growth factors via mTORC1. To analyze Unkempt phosphorylation, we immunoprecipitated Unkempt from cells in the presence or the absence of the mTORC1 inhibitor rapamycin and used mass spectrometry to identify mTORC1-dependent phosphorylated residues. This analysis showed that mTORC1-dependent phosphorylation is concentrated in a serine-rich intrinsically disordered region in the C-terminal half of Unkempt. We also found that Unkempt physically interacts with and is directly phosphorylated by mTORC1 through binding to the regulatory-associated protein of mTOR, Raptor. Furthermore, analysis in the developing brain of mice lacking TSC1 expression showed that phosphorylation of Unkempt is mTORC1 dependent in vivo. Finally, mutation analysis of key serine/threonine residues in the serine-rich region indicates that phosphorylation inhibits the ability of Unkempt to induce a bipolar morphology. Phosphorylation within this serine-rich region thus profoundly affects the ability of Unkempt to regulate cellular morphogenesis. Taken together, our findings reveal a novel molecular link between mTORC1 signaling and cellular morphogenesis.
登录
查看更多内容
DOI：
10.1083/jcb.200403069
发表时间：
2004-07-19
期刊：
The Journal of cell biology
影响因子：
--
作者：
Harrington LS;Findlay GM;Gray A;Tolkacheva T;Wigfield S;Rebholz H;Barnett J;Leslie NR;Cheng S;Shepherd PR;Gout I;Downes CP;Lamb RF
通讯作者：
Lamb RF
影响因子：
9.9
作者：
通讯作者：
--
影响因子：
3.5
作者：
Anderl, Stefanie;Freeland, Megan;Goto, June
通讯作者：
Goto, June
DOI：
10.1126/science.1199498
发表时间：
2011-06-10
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Hsu PP;Kang SA;Rameseder J;Zhang Y;Ottina KA;Lim D;Peterson TR;Choi Y;Gray NS;Yaffe MB;Marto JA;Sabatini DM
通讯作者：
Sabatini DM
影响因子：
14.9
作者：
Ishida T;Kinoshita K
通讯作者：
Kinoshita K