Proximity interactome of LC3B in normal growth conditions
Proximity interactome of LC3B in normal growth conditions
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DOI：
10.1101/2021.10.08.463639
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发表时间：
2021-10
期刊：
影响因子：
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通讯作者：
M. Nollet;A. Agrotis;Fanourios Michailidis;Arran Dokal;V. Rajeeve;J. Burden;T. Nightingale;P. Cutillas;R. Ketteler;S. Kermorgant
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文献类型：
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作者：
M. Nollet;A. Agrotis;Fanourios Michailidis;Arran Dokal;V. Rajeeve;J. Burden;T. Nightingale;P. Cutillas;R. Ketteler;S. Kermorgant
Lc3(轻链3)是自噬的关键分子，自噬是促进细胞内稳态的一种主要的应激反应蛋白分解途径。它协调自噬小体的形成和成熟，并招募货物在自噬小体-溶酶体融合时进一步降解。为了协调其功能，LC3与自噬体内和外膜上的多个蛋白质结合，但这些相互作用的全面程度尚不清楚。此外，在自噬以外的其他细胞位置也有越来越多的报道，细胞结果并不完全清楚，也不都与自噬有关。此外，LC3的新功能以及自噬可以在正常条件下生长的细胞中发生，从而在非应激条件下生长。更好地了解在正常生长条件下靠近Lc3的分子将有助于理解Lc3在自噬和其他细胞生物学功能中的作用。使用基于APEX2的蛋白质组学方法，我们已经在非应激条件下检测到了与特征良好的LC3B亚型接近的407个蛋白质。这些包括已知和新的LC3B邻近蛋白，与各种细胞定位和生物学功能相关。其中69个蛋白含有一个假定的LIR(Lc3相互作用区)，其中41个没有报道与自噬相关。通过共免疫沉淀和共免疫荧光验证了几个APEX2的命中结果。这项研究揭示了LC3B的全球相互作用组，并揭示了新的LC3B相互作用因子，而与LC3B的定位和功能无关。这一知识可以被用来更好地理解LC3B在自噬和非自噬细胞过程中的作用。
LC3 (Light Chain 3) is a key player of autophagy, a major stress-responsive proteolysis pathway promoting cellular homeostasis. It coordinates the formation and maturation of autophagosomes and recruits cargo to be further degraded upon autophagosome-lysosome fusion. To orchestrate its functions, LC3 binds to multiple proteins from the autophagosomes’ inner and outer membranes, but the full extent of these interactions is not known. Moreover, LC3 has been increasingly reported in other cellular locations than the autophagosome, with cellular outcome not fully understood and not all related to autophagy. Furthermore, novel functions of LC3 as well as autophagy can occur in cells growing in a normal medium thus in non-stressed conditions. A better knowledge of the molecule in proximity to LC3 in normal growth conditions will improve the understanding of LC3 function in autophagy and in other cell biology function. Using an APEX2 based proteomic approach, we have detected 407 proteins in proximity to the well-characterised LC3B isoform in non-stress conditions. These include known and novel LC3B proximity proteins, associated with various cell localisation and biological functions. Sixty-nine of these proteins contain a putative LIR (LC3 Interacting Region) including 41 not reported associated to autophagy. Several APEX2 hits were validated by co-immunoprecipitation and co-immunofluorescence. This study uncovers the LC3B global interactome and reveals novel LC3B interactors, irrespective of LC3B localisation and function. This knowledge could be exploited to better understand the role of LC3B in autophagy and non-autophagy cellular processes.