Defining the TLT-1 interactome from resting and activated human platelets
Defining the TLT-1 interactome from resting and activated human platelets
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从静息和活化的人血小板中定义 TLT-1 相互作用组
DOI：
10.1016/j.jprot.2020.103638
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发表时间：
2020
影响因子：
3.3
通讯作者：
Melendez, Loyda M.
中科院分区：
文献类型：
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作者：
Schmoker, Anna M.;Perez Pearson, Leishla M.;Cruz, Claudia;Colon Flores, Luis G.;Branfeild, Siobhan;Pagán Torres, Fabiola D.;Fonseca, Karmen;Cantres, Yadira M.;Salgado Ramirez, Carla A.;Melendez, Loyda M.
髓样细胞表达触发受体（TREM）蛋白家族是一类在免疫细胞中表达的I型跨膜蛋白，在先天性和适应性免疫应答中发挥重要作用。TREM家族成员TREM样转录物1（TLT-1，也称为TREML 1）在巨核细胞中表达并包装成血小板颗粒。TLT-1结合纤维蛋白原，并在炎症损伤引发的出血中发挥作用。在这里，我们描述了一个蛋白质组学屏幕，映射TLT-1相互作用组在休息和活化的人血小板。几种鉴定的TLT-1相互作用物参与细胞粘附和迁移以及血小板活化。在免疫共沉淀/免疫印迹实验中对选定的相互作用物（包括β3-整联蛋白、RACK 1、GRB 2和Rabs 5A、7和11 A）进行了额外表征。最后，在免疫沉淀的TLT-1上发现了几个磷酸化位点，包括Thr 280，一个新的，在TLT-1 ITIM调控序列附近的保守残基上的受调控位点。SignificancePlatelet功能依赖于从胞内囊泡或颗粒中分泌活性分子，其中含有可溶性和膜结合蛋白，这些蛋白对血小板聚集、凝血反应和病原体防御机制至关重要。TLT-1被隔离在α-颗粒中并转运至质膜，在炎症损伤后的止血中发挥独特作用。尽管已知TLT-1在血小板生物学中的重要性，但我们对TLT-1机制信号传导的了解有限。本研究定义了静息和活化人类血小板中的TLT-1相互作用组，鉴定了几种新的TLT-1相互作用物以及TLT-1磷酸化位点，所有这些都可能在血小板聚集动力学中具有信号传导意义。
The triggering receptor expressed on myeloid cells (TREM) protein family forms a class of type I transmembrane proteins expressed in immune cells that play important roles in innate and adaptive immune responses. The TREM family member TREM-like transcript 1 (TLT-1, also TREML1) is expressed in megakaryocytes and packaged into platelet granules. TLT-1 binds fibrinogen and plays a role in bleeding initiated by inflammatory insults. Here, we describe a proteomics screen that maps the TLT-1 interactome in resting and activated human platelets. Several identified TLT-1 interactors are involved in cell adhesion and migration, as well as platelet activation. Select interactors, including β3-integrin, RACK1, GRB2, and Rabs 5A, 7, and 11A, were additionally characterized in co-immunoprecipitation/immunoblotting experiments. Finally, several phosphorylation sites were found on immunoprecipitated TLT-1, including Thr280, a novel, regulated site on a conserved residue near the TLT-1 ITIM regulatory sequence.SignificancePlatelet function relies on the secretion of active molecules from intracellular vesicles, or granules, which contain soluble and membrane-bound proteins that are essential for platelet aggregation, coagulation reactions, and pathogen defense mechanisms. TLT-1 is sequestered in α-granules and transported to the plasma membrane, where it plays a unique role in hemostasis after inflammatory insults. Despite the known importance of TLT-1 in platelet biology, our knowledge of TLT-1 mechanistic signaling is limited. This study defines the TLT-1 interactome in resting and active human platelets, identifying several novel TLT-1 interactors, as well as TLT-1 phosphorylation sites, all with likely signaling implications in platelet aggregation dynamics.