Department of Applied Chemistry, University of Toyama 3190 Gofuku, Toyama, 930-855, Japan.
Japan Science and Technology Agency (JST), ERATO Ito Glycotrilogy Project, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
Biochem Biophys Res Commun. 2021 Jan 15;536:52-58. doi: 10.1016/j.bbrc.2020.12.023. Epub 2020 Dec 25.
The lectin chaperones calnexin (CNX) and calreticulin (CRT) localized in the endoplasmic reticulum play important roles in glycoprotein quality control. Although the interaction between these lectin chaperones and ERp57 is well known, it has been recently reported that endoplasmic reticulum protein 29 (ERp29), a member of PDI family, interacts with CNX and CRT. The biochemical function of ERp29 is unclear because it exhibits no ERp57-like redox activity. In this study, we addressed the possibility that ER chaperones CNX and CRT are connected via ERp29, based on our observation that ERp29 exists as a dimer. As a result, we showed that CNX dimerizes through ERp29. These results endorse the hypothesis that ERp29 serves as a bridge that links two molecules of CNX. Also, we showed that similar complexes such as CNX-CRT were formed via ERp29.
内质网中的凝集素伴侣蛋白 calnexin (CNX) 和 calreticulin (CRT) 在糖蛋白质量控制中发挥重要作用。虽然这些凝集素伴侣蛋白与 ERp57 的相互作用已被广泛研究，但最近有报道称，PDI 家族的成员内质网蛋白 29 (ERp29) 与 CNX 和 CRT 相互作用。由于 ERp29 不表现出 ERp57 样的氧化还原活性，其生化功能尚不清楚。在这项研究中，我们基于 ERp29 存在二聚体的观察结果，提出了 ER 伴侣蛋白 CNX 和 CRT 通过 ERp29 连接的可能性。结果表明，CNX 通过 ERp29 二聚化。这些结果支持了 ERp29 作为连接两个 CNX 分子的桥梁的假设。此外，我们还表明，类似的复合物，如 CNX-CRT，也通过 ERp29 形成。
