The multidomain protein Trio binds the LAR transmembrane tyrosine phosphatase, contains a protein kinase domain, and has separate rac-specific and rho-specific guanine nucleotide exchange factor domains
The multidomain protein Trio binds the LAR transmembrane tyrosine phosphatase, contains a protein kinase domain, and has separate rac-specific and rho-specific guanine nucleotide exchange factor domains
复制标题
DOI：
10.1073/pnas.93.11.5466
复制
发表时间：
1996-05-28
影响因子：
11.1
通讯作者：
Streuli, M
中科院分区：
文献类型：
--
作者：
Debant, A;SerraPages, C;Streuli, M
rho样GTP结合蛋白在调节细胞生长和肌动蛋白聚合中起重要作用。这些分子开关由鸟嘌呤核苷酸交换因子（GEF）正向调节，促进GDP交换为GTP。使用的相互作用陷阱测定，以确定候选蛋白结合的LAR跨膜蛋白酪氨酸磷酸酶（PTYP）的胞质区域，我们分离的cDNA编码的2861个氨基酸的蛋白质称为三，包含三个酶结构域：两个功能GEF结构域和蛋白丝氨酸/苏氨酸激酶（PSK）结构域。其中一个Trio GEF结构域（Trio GEF-D1）具有rac特异性GEF活性，而另一个Trio GEF结构域（Trio GEF-D2）具有rho特异性活性。C-末端PSK结构域与Ig样结构域相邻，并且与钙/钙调蛋白依赖性激酶最相似，例如平滑肌肌球蛋白轻链激酶，其同样含有相关的Ig样结构域。在N末端附近，Trio有四个血影蛋白样重复序列，可能在细胞内靶向中发挥作用。北方印迹分析表明Trio具有广泛的组织分布。Trio似乎仅在丝氨酸残基上磷酸化，表明Trio不是LAR底物，而是与LAR形成复合物。由于LAR PTP 3定位于局灶性粘连的末端，我们认为LAR和三重GEF/PSK可能协调细胞迁移所需的细胞基质和细胞骨架重排。
rho-like GTP binding proteins play an essential role in regulating cell growth and actin polymerization. These molecular switch are positively regulated by guanine nucleotide exchange factors (GEFs) that promote the exchange of GDP for GTP. Using the interaction-trap assay to identify candidate proteins that bind the cytoplasmic region of the LAR transmembrane protein tyrosine phosphatase (PTPase), we isolated a cDNA encoding a 2861-amino acid protein termed Trio that contains three enzyme domains: two functional GEF domains and a protein serine/threonine kinase (PSK) domain. One of the Trio GEF domains (Trio GEF-D1) has rac-specific GEF activity, while the other Trio GEF domain (Trio GEF-D2) has rho-specific activity. The C-terminal PSK domain is adjacent to an Ig-like domain and is most similar to calcium/calmodulin-dependent kinases, such as smooth muscle myosin light chain kinase which similarly contains associated Ig-like domains. Near the N terminus, Trio has four spectrin-like repeats that may play a role in intracellular targeting. Northern blot analysis indicates that Trio has a broad tissue distribution. Trio appears to be phosphorylated only on serine residues, suggesting that Trio is not a LAR substrate, but rather that it forms a complex with LAR. As the LAR PTPase localizes to the ends of focal adhesions, we propose that LAR and the Trio GEF/PSK may orchestrate cell-matrix and cytoskeletal rearrangements necessary for cell migration.