Roles of COPII-mediated vesicular transport in higher animals

外壳蛋白复合物II （COPII）包被的囊泡介导蛋白质从内质网（ER）到高尔基体的运输。在这项研究中，我们分析了两个copii相互作用蛋白p125和Sec16B的功能。我们发现p125的缺失减少了Sec23 （COPII的内层成分）和Sec31 （COPII的外层成分）之间的相互作用，这表明在COPII的组装中起作用。我们还证明了Sec16B参与了Pex16（一种过氧化物酶体膜蛋白）从内质网到过氧化物酶体的运输。我们对突变Sec16B蛋白的研究结果表明，内质网出口位点（COPII囊泡形成的内质网亚域）不参与这一过程。此外，我们发现Sec16B可能参与HeLa细胞脂滴的生物形成。

Coat protein complex II (COPII)-coated vesicles mediate protein transport from the endoplasmic reticulum (ER) to the Golgi apparatus. In this study, we analyzed functions of two COPII-interacting proteins, p125 and Sec16B. We found that loss of p125 reduced the interaction between Sec23 (an inner layer component of COPII) and Sec31 (an outer layer component of COPII), suggesting a role in the assembly of COPII. We also demonstrated that Sec16B is involved in the transport of Pex16, a peroxisomal membrane protein, from the ER to peroxisomes. Our results with mutant Sec16B proteins suggest that ER exit sites, which are an ER subdomain where COPII vesicles are formed, are not involved in this process. In addition, we found that Sec16B might be involved in lipid droplet biogenesis in HeLa cells.