Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, AV, The Netherlands.
Department of Biology, University of Fribourg, Fribourg, Switzerland.
Autophagy. 2024 Oct;20(10):2323-2337. doi: 10.1080/15548627.2024.2366749. Epub 2024 Jul 3.
Autophagosome biogenesis is a complex process orchestrated by dynamic interactions between Atg (autophagy-related) proteins and characterized by the turnover of specific cargoes, which can differ over time and depending on how autophagy is stimulated. Proteomic analyses are central to uncover protein-protein interaction networks and when combined with proximity-dependent biotinylation or proximity labeling (PL) approaches, they also permit to detect transient and weak interactions. However, current PL procedures for yeast , one of the leading models for the study of autophagy, do not allow to keep temporal specificity and thus identify interactions and cargoes at a precise time point upon autophagy induction. Here, we present a new ascorbate peroxidase 2 (APEX2)-based PL protocol adapted to yeast that preserves temporal specificity and allows uncovering neighbor proteins by either western blot or proteomics. As a proof of concept, we applied this new method to identify Atg8 and Atg9 interactors and detected known binding partners as well as potential uncharacterized ones in rich and nitrogen starvation conditions. Also, as a proof of concept, we confirmed the spatial proximity interaction between Atg8 and Faa1. We believe that this protocol will be a new important experimental tool for all those researchers studying the mechanism and roles of autophagy in yeast, but also other cellular pathways in this model organism.: APEX2, ascorbate peroxidase 2, Atg, autophagy-related; BP, biotin phenol; Cvt, cytoplasm-to-vacuole targeting; ER, endoplasmic reticulum; LN2, liquid nitrogen; MS, mass spectrometry; PAS, phagophore assembly site; PL, proximity labeling; PE, phosphatidylethanolamine; PPINs, protein-protein interaction networks; PPIs, protein-protein interactions; RT, room temperature; SARs, selective autophagy receptors; WT, wild-type.
自噬体生物发生是一个复杂的过程,由 Atg(自噬相关)蛋白之间的动态相互作用来协调,并以特定货物的周转为特征,这些货物可以随时间和自噬的刺激方式而变化。蛋白质组学分析是揭示蛋白质-蛋白质相互作用网络的核心方法,当与邻近依赖性生物素化或邻近标记(PL)方法结合使用时,它们还可以检测瞬时和弱相互作用。然而,目前用于酵母的 PL 程序(自噬研究的主要模型之一)不允许保持时间特异性,因此无法在自噬诱导时在精确时间点识别相互作用和货物。在这里,我们提出了一种新的基于抗坏血酸过氧化物酶 2(APEX2)的 PL 方案,该方案适用于酵母,可以保留时间特异性,并通过 Western blot 或蛋白质组学方法揭示邻近蛋白。作为概念验证,我们应用这种新方法来鉴定 Atg8 和 Atg9 的相互作用体,并在丰富和氮饥饿条件下检测到已知的结合伴侣以及潜在的未表征的相互作用体。此外,作为概念验证,我们证实了 Atg8 和 Faa1 之间的空间接近相互作用。我们相信,该方案将成为研究酵母自噬机制和作用的所有研究人员的一个新的重要实验工具,也将成为该模式生物中其他细胞途径的重要工具。:APEX2,抗坏血酸过氧化物酶 2;Atg,自噬相关;BP,生物素酚;Cvt,细胞质到液泡靶向;ER,内质网;LN2,液氮;MS,质谱;PAS,噬菌斑组装位点;PL,邻近标记;PE,磷脂酰乙醇胺;PPINs,蛋白质-蛋白质相互作用网络;PPIs,蛋白质-蛋白质相互作用;RT,室温;SARS,选择性自噬受体;WT,野生型。