Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany.
Institute for Physiological Chemistry, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany.
Nat Commun. 2022 Jul 23;13(1):4262. doi: 10.1038/s41467-022-31831-1.
In their GTP-bound (active) form, Rab proteins interact with effector proteins that control downstream signaling. One such Rab15 effector is Rep15, which is known to have a role in receptor recycling from the endocytic recycling compartment but otherwise remains poorly characterized. Here, we report the characterization of the Rep15:Rab15 interaction and identification of Rab3 paralogs and Rab34 as Rep15 interacting partners from a yeast two-hybrid assay. Biochemical validation of the interactions is presented and crystal structures of the Rep15:Rab3B and Rep15:Rab3C complexes provide additional mechanistic insight. We find that Rep15 adopts a globular structure that is distinct from other reported Rab15, Rab3 and Rab34 effectors. Structure-based mutagenesis experiments explain the Rep15:Rab interaction specificity. Rep15 depletion in U138MG glioblastoma cells impairs cell proliferation, cell migration and receptor recycling, underscoring the need for further clarification of the role of Rep15 in cancer.
在其 GTP 结合（活性）形式中，Rab 蛋白与控制下游信号转导的效应蛋白相互作用。Rab15 的一种效应蛋白是 Rep15，已知其在受体从内体再循环隔室的再循环中起作用，但除此之外，其功能仍知之甚少。在这里，我们报告了 Rep15：Rab15 相互作用的特征，并从酵母双杂交测定中鉴定了 Rab3 同源物和 Rab34 是 Rep15 的相互作用伙伴。相互作用的生化验证，并提供了 Rep15：Rab3B 和 Rep15：Rab3C 复合物的晶体结构，提供了额外的机制见解。我们发现 Rep15 采用了与其他报道的 Rab15、Rab3 和 Rab34 效应蛋白不同的球形结构。基于结构的诱变实验解释了 Rep15：Rab 相互作用的特异性。U138MG 神经胶质瘤细胞中 Rep15 的缺失会损害细胞增殖、细胞迁移和受体再循环，这突显了进一步阐明 Rep15 在癌症中的作用的必要性。
