Palmitoylation-Dependent Plasma Membrane Transport but Lipid Raft-Independent Signaling by Linker for Activation of T Cells1
Palmitoylation-Dependent Plasma Membrane Transport but Lipid Raft-Independent Signaling by Linker for Activation of T Cells1
复制标题
用于激活 T 细胞的连接子的棕榈酰化依赖性质膜运输但不依赖脂筏的信号传导1
作者：
M. Hundt;Yohsuke Harada;Lauren De Giorgio;N. Tanimura;Weiguo Zhang;A. Altman
活化T细胞连接蛋白(LAT)是一种双棕榈酸化的跨膜接头蛋白，对T细胞的发育和激活至关重要。然而，LAT是否需要棕榈酰化和/或脂筏定位才能发挥其功能仍存在争议。为了解决这个问题，我们使用了生化、成像和遗传方法的组合，包括LAT逆转录病毒转导的小鼠T细胞和骨髓嵌合体小鼠。跨膜LAT的非棕榈酰化、非脂筏驻留突变体不能重建骨髓嵌合小鼠的T细胞发育。该突变体不存在于质膜上，主要局限于高尔基体。一种嵌合的、非棕榈酰化的LAT蛋白，由针对PM的Src激酶N端序列和LAT细胞质结构域(Src-LAT)组成，定位于PM中的外周膜蛋白，但在脂筏外。然而，Src-LAT恢复了T细胞的发育和激活。最后，Cys26(但不是Cys29)上的LAT的单丝裂化是其PM转运和功能所必需的，也是充分的。因此，LAT在T细胞中的功能需要其PM而不是RAFT定位，即使在表达为外周膜蛋白时也是如此。此外，LAT棕榈酰化主要作为其PM运输所需的分选信号发挥作用。
Linker for activation of T cells (LAT) is a dually palmitoylated transmembrane adaptor protein essential for T cell development and activation. However, whether LAT palmitoylation and/or lipid raft localization are required for its function is controversial. To address this question, we used a combination of biochemical, imaging, and genetic approaches, including LAT retrovirus-transduced mouse T cells and bone marrow chimeric mice. A nonpalmitoylated, non-lipid raft-residing mutant of transmembrane LAT could not reconstitute T cell development in bone marrow chimeric mice. This mutant was absent from the plasma membrane (PM) and was restricted mainly to the Golgi apparatus. A chimeric, nonpalmitoylated LAT protein consisting of the PM-targeting N-terminal sequence of Src kinase and the LAT cytoplasmic domain (Src-LAT) localized as a peripheral membrane protein in the PM, but outside lipid rafts. Nevertheless, Src-LAT restored T cell development and activation. Lastly, monopalmitoylation of LAT on Cys26 (but not Cys29) was required and sufficient for its PM transport and function. Thus, the function of LAT in T cells requires its PM, but not raft, localization, even when expressed as a peripheral membrane protein. Furthermore, LAT palmitoylation functions primarily as a sorting signal required for its PM transport.
影响因子：
32.4
作者：
R. Xavier;Todd Brennan;Qingqin Li;Christine McCormack;B. Seed
通讯作者：
R. Xavier;Todd Brennan;Qingqin Li;Christine McCormack;B. Seed
影响因子：
4.4
作者：
Zhang, WG;Irvin, BJ;Samelson, LE
通讯作者：
Samelson, LE