Cell Biology of Infection Laboratory, The Francis Crick Institute, London NW1 1AT, UK; Division of Medicine, University College London, London WC1E 6JF, UK.
Structural Biology of Disease Processes Laboratory, The Francis Crick Institute, London NW1 1AT, UK; Structural Biology STP, The Francis Crick Institute, London NW1 1AT, UK.
Mol Cell. 2024 Aug 8;84(15):2966-2983.e9. doi: 10.1016/j.molcel.2024.07.003. Epub 2024 Jul 31.
Defects in organellar acidification indicate compromised or infected compartments. Recruitment of the autophagy-related ATG16L1 complex to pathologically neutralized organelles targets ubiquitin-like ATG8 molecules to perturbed membranes. How this process is coupled to proton gradient disruption is unclear. Here, we reveal that the VH subunit of the vacuolar ATPase (V-ATPase) proton pump binds directly to ATG16L1. The VH/ATG16L1 interaction only occurs within fully assembled V-ATPases, allowing ATG16L1 recruitment to be coupled to increased V-ATPase assembly following organelle neutralization. Cells lacking VH fail to target ATG8s during influenza infection or after activation of the immune receptor stimulator of interferon genes (STING). We identify a loop within VH that mediates ATG16L1 binding. A neuronal VH isoform lacks this loop and is associated with attenuated ATG8 targeting in response to ionophores in primary murine and human iPSC-derived neurons. Thus, VH controls ATG16L1 recruitment following proton gradient dissipation, suggesting that the V-ATPase acts as a cell-intrinsic damage sensor.
细胞器酸化缺陷表明隔室功能受损或被感染。自噬相关 ATG16L1 复合物被募集到病理性中和的细胞器，将泛素样 ATG8 分子靶向到受到干扰的膜上。目前尚不清楚这个过程是如何与质子梯度破坏偶联的。在这里，我们揭示了液泡型 ATP 酶 (V-ATPase) 质子泵的 VH 亚基直接与 ATG16L1 结合。只有在完全组装的 V-ATPases 中，才会发生 VH/ATG16L1 相互作用，从而允许在细胞器中和后，将 ATG16L1 的募集与 V-ATPase 组装的增加偶联起来。缺乏 VH 的细胞在流感感染或干扰素基因刺激物免疫受体 (STING) 激活后无法靶向 ATG8。我们确定了 VH 内介导 ATG16L1 结合的环。神经元 VH 同工型缺乏此环，并且与对原代鼠和人 iPSC 衍生神经元中的离子载体的 ATG8 靶向作用减弱有关。因此，VH 控制质子梯度耗散后 ATG16L1 的募集，表明 V-ATPase 充当细胞内固有损伤传感器。
