Kabouridis Panagiotis S, Isenberg David A, Jury Elizabeth C
William Harvey Research Institute , Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London, UK.
Mol Membr Biol. 2011 Oct-Nov;28(7-8):487-94. doi: 10.3109/09687688.2011.624990.
We have shown previously that in T cells, LAT co-immunoprecipitates with the active but not the inactive-'closed' form of Lck, and that this interaction impacts negatively on Lck activity. Here we confirm that activation of T cells induced a transient LAT/Lck association within 4 min after stimulation, returning to basal levels by 30 min. Interestingly, autoimmune T cells isolated from patients with systemic lupus erythematosus, which contain a larger pool of active Lck and LAT, exhibited increased LAT/Lck association compared to healthy controls. To identify the domain of LAT responsible for its interaction with active Lck, a series of LAT truncation mutants were constructed and tested in co-immunoprecipitation experiments. We found that the segment comprising residues 112-126 of human LAT is required for its interaction with Lck. This domain is rich in negatively charged amino acids and is conserved among different species. Therefore, in addition to the conserved tyrosines, the 112-126 domain identified here could be important for certain functions of LAT in T cells.
我们之前已经表明，在T细胞中，LAT与活性形式而非无活性的“封闭”形式的Lck共免疫沉淀，并且这种相互作用对Lck活性有负面影响。在此我们证实，T细胞的激活在刺激后4分钟内诱导了短暂的LAT/Lck结合，到30分钟时恢复到基础水平。有趣的是，从系统性红斑狼疮患者中分离出的自身免疫性T细胞含有更大的活性Lck和LAT池，与健康对照相比，其LAT/Lck结合增加。为了确定LAT中负责其与活性Lck相互作用的结构域，构建了一系列LAT截短突变体并在共免疫沉淀实验中进行测试。我们发现，人LAT的112 - 126位残基组成的片段是其与Lck相互作用所必需的。该结构域富含带负电荷的氨基酸，并且在不同物种中保守。因此，除了保守的酪氨酸外，这里鉴定出的112 - 126结构域可能对LAT在T细胞中的某些功能很重要。
