Center for Cooperative Research in Biosciences (CIC bioGUNE), Bilbao, Spain.
GAIKER Technology Centre, Basque Research and Technology Alliance (BRTA), Zamudio, Spain.
Protein Sci. 2024 May;33(5):e4980. doi: 10.1002/pro.4980.
Endosomal trafficking ensures the proper distribution of lipids and proteins to various cellular compartments, facilitating intracellular communication, nutrient transport, waste disposal, and the maintenance of cell structure. Retromer, a peripheral membrane protein complex, plays an important role in this process by recruiting the associated actin-polymerizing WASH complex to establish distinct sorting domains. The WASH complex is recruited through the interaction of the VPS35 subunit of retromer with the WASH complex subunit FAM21. Here, we report the identification of two separate fragments of FAM21 that interact with VPS35, along with a third fragment that binds to the VPS29 subunit of retromer. The crystal structure of VPS29 bound to a peptide derived from FAM21 shows a distinctive sharp bend that inserts into a conserved hydrophobic pocket with a binding mode similar to that adopted by other VPS29 effectors. Interestingly, despite the network of interactions between FAM21 and retromer occurring near the Parkinson's disease-linked mutation (D620N) in VPS35, this mutation does not significantly impair the direct association with FAM21 in vitro.
内体运输确保了脂质和蛋白质在各种细胞隔室中的正确分布，促进了细胞内通讯、营养物质运输、废物处理和细胞结构的维持。Retromer 是一种外围膜蛋白复合物，通过招募相关的肌动蛋白聚合 WASH 复合物来建立不同的分拣结构域，在这个过程中起着重要作用。WASH 复合物通过 retromer 的 VPS35 亚基与 WASH 复合物亚基 FAM21 的相互作用被招募。在这里，我们报告了两个与 VPS35 相互作用的 FAM21 的独立片段的鉴定，以及与 retromer 的 VPS29 亚基结合的第三个片段。与源自 FAM21 的肽结合的 VPS29 的晶体结构显示出独特的尖锐弯曲，插入到一个保守的疏水性口袋中，其结合模式类似于其他 VPS29 效应物所采用的模式。有趣的是，尽管 FAM21 和 retromer 之间的相互作用网络发生在 VPS35 中与帕金森病相关的突变（D620N）附近，但该突变并没有显著削弱体外与 FAM21 的直接关联。
