State Key Laboratory of Bio-Organic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
School of Chemistry and Materials Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 1 Sub-lane Xiangshan, Hangzhou 310024, China.
Sci Adv. 2023 Mar;9(9):eadf0824. doi: 10.1126/sciadv.adf0824. Epub 2023 Mar 1.
Macroautophagy plays crucial roles in the regulation of cellular physiology and requires de novo synthesis of double-membrane autophagosomes, which relies on a specific interaction between autophagy-related 16L1 (ATG16L1) and WD repeat domain phosphoinositide-interacting protein 2b (WIPI2b). However, the molecular mechanism governing the interaction of ATG16L1 with WIPI2b remains elusive. Here, we find that ATG16L1 has two distinct binding sites for interacting with WIPI2b, the previously reported WIPI2b-binding site (WBS1) and the previously unidentified site (WBS2). We determine the crystal structures of WIPI2b with ATG16L1 WBS1 and WBS2, respectively, and elucidate the molecular mechanism underpinning the recruitment of ATG16L1 by WIPI2b. Moreover, we uncover that ATG16L1 WBS2 and its binding mode with WIPI2b is well conserved from yeast to mammals, unlike ATG16L1 WBS1. Last, our cell-based functional assays demonstrate that both ATG16L1 WBS1 and WBS2 are required for the effective autophagic flux. In conclusion, our findings provide mechanistic insights into the key ATG16L1/WIPI2b interaction in autophagy.
自噬在调节细胞生理中起着至关重要的作用，需要从头合成双层自噬体，这依赖于自噬相关蛋白 16L1（ATG16L1）和 WD 重复域磷酸肌醇相互作用蛋白 2b（WIPI2b）之间的特异性相互作用。然而，调控 ATG16L1 与 WIPI2b 相互作用的分子机制仍不清楚。在这里，我们发现 ATG16L1 有两个与 WIPI2b 相互作用的不同结合位点，即先前报道的 WIPI2b 结合位点（WBS1）和先前未鉴定的位点（WBS2）。我们分别确定了 WIPI2b 与 ATG16L1 WBS1 和 WBS2 的晶体结构，并阐明了 WIPI2b 募集 ATG16L1 的分子机制。此外，我们发现从酵母到哺乳动物，ATG16L1 WBS2 及其与 WIPI2b 的结合模式都与 WBS1 不同，且具有很好的保守性。最后，我们的细胞功能测定表明，ATG16L1 WBS1 和 WBS2 都对有效的自噬通量是必需的。总之，我们的研究结果为自噬中关键的 ATG16L1/WIPI2b 相互作用提供了机制见解。
