<p>The general consensus is that the vacuolar-type H<sup>+</sup>-translocating ATPase (V-ATPase) is critical for macroautophagy/autophagy. However, there is a fundamental conundrum because follicular lymphoma-associated mutations in the V-ATPase result in lysosomal/vacuolar deacidification but elevated autophagy activity under nutrient-replete conditions and the underlying mechanisms remain unclear. Here, working in yeast, we show that V-ATPase dysfunction activates a selective autophagy flux termed “V-ATPase-dependent autophagy “. By combining transcriptomic and proteomic profiling, along with genome-wide suppressor screening approaches, we found that V-ATPase-dependent autophagy is regulated through a unique mechanism distinct from classical nitrogen starvation-induced autophagy. Tryptophan metabolism negatively regulates V-ATPase-dependent autophagy via two parallel effectors. On the one hand, it activates ribosome biogenesis, thus repressing the translation of the transcription factor Gcn4/ATF4. On the other hand, tryptophan fuels NAD<sup>+</sup> de novo biosynthesis to inhibit autophagy. These results provide an explanation for the mutational activation of autophagy seen in follicular lymphoma patients.</p>

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V-ATPase-dependent induction of selective autophagy

  • Yuxiang Huang,
  • Dimitra Dialynaki,
  • Yuchen Lei,
  • Zhihai Zhang,
  • Charles R. Evans,
  • Daniel J. Klionsky

摘要

The general consensus is that the vacuolar-type H+-translocating ATPase (V-ATPase) is critical for macroautophagy/autophagy. However, there is a fundamental conundrum because follicular lymphoma-associated mutations in the V-ATPase result in lysosomal/vacuolar deacidification but elevated autophagy activity under nutrient-replete conditions and the underlying mechanisms remain unclear. Here, working in yeast, we show that V-ATPase dysfunction activates a selective autophagy flux termed “V-ATPase-dependent autophagy “. By combining transcriptomic and proteomic profiling, along with genome-wide suppressor screening approaches, we found that V-ATPase-dependent autophagy is regulated through a unique mechanism distinct from classical nitrogen starvation-induced autophagy. Tryptophan metabolism negatively regulates V-ATPase-dependent autophagy via two parallel effectors. On the one hand, it activates ribosome biogenesis, thus repressing the translation of the transcription factor Gcn4/ATF4. On the other hand, tryptophan fuels NAD+ de novo biosynthesis to inhibit autophagy. These results provide an explanation for the mutational activation of autophagy seen in follicular lymphoma patients.