Vacuolar processing enzyme translocates to the vacuole through the autophagy pathway to induce programmed cell death

Paula Teper-Bamnolker, Raz Danieli, Hadas Peled-Zehavi, Eduard Belausov, Mohamad Abu-Abied, Tamar Avin-Wittenberg, Einat Sadot, Dani Eshel

Research output: Contribution to journalArticlepeer-review


The caspase-like vacuolar processing enzyme (VPE) is a key factor in programmed cell death (PCD) associated with plant stress responses. Growth medium lacking a carbon source and dark conditions caused punctate labeling of 35S::VPE1-GFP (StVPE1-GFP) in potato leaves. Under conditions of carbon starvation, VPE activity and PCD symptoms strongly increased in BY-2 cells, but to a much lesser extent in VPE-RNAi BY-2 cells. During extended exposure to carbon starvation, VPE expression and activity levels peaked, with a gradual increase in BY-2 cell death. Histological analysis of StVPE1-GFP in BY-2 cells showed that carbon starvation induces its translocation from the endoplasmic reticulum to the central vacuole through tonoplast engulfment. Exposure of BY-2 culture to the macroautophagy/autophagy inhibitor concanamycin A led to, along with an accumulation of autophagic bodies, accumulation of StVPE1-GFP in the cell vacuole. This accumulation did not occur in the presence of 3-methyladenine, an inhibitor of early-stage autophagy. BY-2 cells constitutively expressing RFP-StATG8IL, an autophagosome marker, showed colocalization with the StVPE1-GFP protein in the cytoplasm and vacuole. RNAi silencing of the core autophagy component ATG4 in BY-2 cells reduced VPE activity and cell death. These results are the first to suggest that VPE translocates to the cell vacuole through the autophagy pathway, leading to PCD. Abbreviations: ATG: autophagy related; CLP: caspase-like protease; HR: hypersensitive response; PCD: programmed cell death; St: Solanum tuberosum; VPE: vacuolar processing enzyme.

Original languageEnglish
Pages (from-to)3109-3123
Number of pages15
Issue number10
Early online date19 Dec 2020
StatePublished - 3 Oct 2021


  • Autophagosome
  • BY-2 cells
  • Solanum tuberosum
  • autophagy-related gene
  • carbon starvation
  • caspase-like protease
  • tobacco

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Cell Biology


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