Regulation of membrane traffic between the ER and Golgi by SNARE-associated proteins, ZW10/RINT-1

SNARE（可溶性NSF附着蛋白受体）参与真核细胞囊泡转运途径中的膜融合。我们先前报道了syntaxin 18，一种哺乳动物ER定位的SNARE，与其他SNARE（BNIP 1，p31和Sec 22 b）和外周膜蛋白ZW 10和RINT-1形成复合物。在本研究中，我们研究了ZW 10/RINT-1复合物在内质网和高尔基体之间的膜运输中的功能，并获得了以下结果：1）ZW 10和dynamitin之间的相互作用蛋白质从内质网到高尔基体的运输是由微管运动蛋白dynein-dynactin介导的。我们发现dynamitin，dynactin复合物的一个亚基，和RINT-1结合ZW 10的N-末端区域的竞争方式。ZW 10的N-末端区域与动力素的体内相互作用的证据是通过使用去甲二氢愈创木酸（nordihydroguaiaretic acid）获得的，所述去甲二氢愈创木酸是已知刺激动力蛋白-动力肌动蛋白介导的过程的试剂。这些结果增加了ZW 10在ER膜上通过与dynamitin相互作用而被募集来运输载体的可能性。2）ZW 10与被膜亚基的相互作用在哺乳动物细胞中，COPI包被的囊泡负责蛋白质从ER转运到高尔基体。结合实验表明，β、γ和δ-COPI与ZW 10之间存在弱相互作用，支持ZW 10存在于COPI包被的囊泡上，并作为动力蛋白-动力肌动蛋白受体的观点。3）NAG（Neuroblastoma amplified gene）产物与ZW 10/RINT-1相互作用我们发现NAG是syntaxin 18复合物的一个组分。NAG的N-末端区域与p31的N-末端区域相互作用，并且NAG的C-末端区域结合ZW 10/RINT-1。

SNAREs (Soluble NSF attachment protein receptors) are involved in membrane fusion in the vesicular transport pathways in eukaryotic cells. We previously reported that syntaxin 18, a mammalian ER-localized SNARE, forms a complex with other SNAREs (BNIP1, p31, and Sec22b) and peripheral membrane proteins ZW10, and RINT-1). In the present study, we examined the function of a ZW10/RINT-1 complex in membrane traffic between the ER and the Golgi apparatus, and obtained the following results.1) Interaction between ZW10 and dynamitinProtein transport from the ER to the Golgi is mediated by the microtubule motor protein dynein-dynactin. We found that dynamitin, a subunit of the dynactin complex, and RINT-1 bind to the N-terminal region of ZW10 in a competitive manner. Evidence for the in vivo interaction of the N-terminal region of ZW10 with dynamitin was obtained by using nordihydroguaiaretic acid, a reagent that is known to stimulate dynein-dynactin-mediated processes. These results raise the possibility that ZW10 on the ER membrane is recruited to transport carriers through the interaction with dynamitin.2) Interaction of ZW10 with coatomer subunitsCOPI-coated vesicles are responsible for protein transport from the ER to the Golgi in mammalian cells. Binding experiments revealed that β,γ, and δ-COPI, weakly interact with ZW10, supporting the idea that ZW10 exists on COPI-coated vesicles and acts as a dynein-dynactin receptor.3) The NAG (Neuroblastoma amplified gene) product interacts with ZW10/RINT-1We discovered that NAG is a component of the syntaxin 18 complex. The N-terminal region of NAG interacts with the N-terminal region of p31, and the C-terminal region of NAG bind ZW10/RINT-1.