Dynamic recruitment of the adaptor protein LAT: LAT exists in two distinct intracellular pools and controls its own recruitment
Dynamic recruitment of the adaptor protein LAT: LAT exists in two distinct intracellular pools and controls its own recruitment
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DOI：
10.1242/jcs.00968
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发表时间：
2004-03-01
影响因子：
4
通讯作者：
Collette, Y
中科院分区：
文献类型：
--
作者：
Bonello, G;Blanchard, N;Collette, Y
T细胞激活的整合膜适配器蛋白连接物(LAT)将T细胞受体(TCR)与下游信号连接起来，对T细胞的发育和激活是必不可少的。在这里，我们通过活的T淋巴细胞与抗原提呈细胞相互作用的时间推移视频成像来研究LAT-GFP融合蛋白的动态分布。我们发现LAT形成了两个不同的细胞池，一个在质膜上，另一个与转铁蛋白标记的细胞内隔室共同分布，也包含TCR/CD3相关的Zeta链。LAT在这两个池中的分布取决于LAT在胞质内的残基。质膜相关的LAT在细胞结合形成几秒钟后被招募到免疫突触中，而细胞内池首先被极化，然后在几分钟后被招募。我们进一步表明，LAT胞质内氨基酸残基，特别是Tyr136、175、195和235残基，是其自身募集到免疫突触所必需的，本文确定的膜旁LAT区域(氨基酸32-104)参与了LAT在细胞池中的定位和T细胞信号转导。总之，我们的结果表明，LAT控制着自己在免疫突触的招募，在那里它是信号机制所需的支架蛋白。结果还表明，T细胞的激活可能需要LAT的胞内池。
The integral membrane adaptor protein linker for activation of T cells (LAT) couples the T-cell receptor (TCR) with downstream signalling and is essential for T-cell development and activation. Here, we investigate the dynamic distribution of LAT-GFP fusion proteins by time-lapse video imaging of live T lymphocytes interacting with antigen-presenting cells. We show that LAT forms two distinct cellular pools, one at the plasma membrane and one that co-distributes with transferrin-labelled intracellular compartments also containing the TCR/CD3-associated zeta chain. The distribution of LAT between these two pools is dependent on LAT intracytoplasmic residues. Whereas plasma membrane-associated LAT is recruited to immune synapses after a few seconds of cell conjugate formation, the intracellular pool is first polarized and then recruited after a few minutes. We further show that LAT intracytoplasmic amino acid residues, particularly the Tyr136, 175, 195 and 235 residues, are required for its own recruitment to the immune synapse and that a herein-identified juxtamembrane LAT region (amino acids 32-104) is involved in the localization of LAT in intracellular pools and in T-cell signalling. Altogether, our results demonstrate that LAT controls its own recruitment at the immune synapse, where it is required as a scaffold protein for the signalling machinery. The results also suggest that the intracellular pool of LAT might be required for T-cell activation.