Zhang W, Irvin B J, Trible R P, Abraham R T, Samelson L E
Section on Lymphocyte Signaling, Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-5430, USA.
Int Immunol. 1999 Jun;11(6):943-50. doi: 10.1093/intimm/11.6.943.
The adaptor molecule LAT (linker for activation of T cells) is a palmitoylated integral membrane protein that localizes to the glycolipid-enriched microdomains in the plasma membrane. Upon TCR engagement, LAT becomes phosphorylated on multiple tyrosine residues and then binds several critical signaling molecules. Here, we describe the generation and characterization of a LAT-deficient cell line. Using this cell line, we demonstrate that LAT is required for TCR-mediated Ca2+ mobilization and optimal tyrosine phosphorylation of phospholipase C-gamma1, Vav and SLP-76. LAT is also required for Erk activation, CD69 up-regulation, and AP- and NFAT-mediated gene transcription. We also demonstrate, by reconstituting this cell line with LAT mutants, that the LAT transmembrane domain and palmitoylation at Cys26, but not Cys29, are required for LAT function and TCR signaling. These studies provide further evidence for the crucial role of the LAT molecule, and demonstrate the use of a LAT-deficient cell line for the analysis of LAT structure and function.
衔接分子LAT（T细胞活化连接蛋白）是一种棕榈酰化的整合膜蛋白，定位于质膜中富含糖脂的微结构域。TCR激活后，LAT的多个酪氨酸残基发生磷酸化，然后结合几个关键的信号分子。在此，我们描述了一种LAT缺陷细胞系的产生和特性。利用该细胞系，我们证明LAT是TCR介导的Ca2+动员以及磷脂酶C-γ1、Vav和SLP-76的最佳酪氨酸磷酸化所必需的。LAT也是Erk激活、CD69上调以及AP和NFAT介导的基因转录所必需的。我们还通过用LAT突变体重构该细胞系证明，LAT跨膜结构域和Cys26而非Cys29处的棕榈酰化对于LAT功能和TCR信号传导是必需的。这些研究为LAT分子的关键作用提供了进一步证据，并证明了使用LAT缺陷细胞系分析LAT的结构和功能。
