Proteasome inhibitor MG132 impairs autophagic flux through compromising formation of autophagosomes in Bombyx cells

Ming Ming Ji, Jae Man Lee, Hiroaki Mon, Jian Xu, Tsuneyuki Tatsuke, Takahiro Kusakabe

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

MG132 has been used as a proteasome inhibitor on Bombyx cells, but its physiological effects on autophagy still have not been elucidated. In this study, we find that the lipidated BmAtg8, BmAtg8-PE as an autophagosomal marker protein, is only localized to membranes. Then we established systems to monitor autophagic flux in Bombyx cells: Induction of autophagy reduces exogenous BmAtg8 and exogenous BmAtg8-PE, facilitates formation of autophagosomes indicated by green EGFP-BmAtg8 puncta after cotreatment by Rapamycin and Bafilomycin A1, and causes accumulation of free EGFP from EGFP-BmAtg8 cleavage in autolysosomes. Using these established systems, we find that exposure of MG132 inhibits both basal and Rapamycin-induced autophagy when polyubiquitinated proteins are accumulated markedly in Bombyx cells. Interestingly, we reveal that attenuation of autophagy in these cells is ascribed as distinct suppression of formation of autophagosomes after MG132 treatment.

Original languageEnglish
Pages (from-to)690-696
Number of pages7
JournalBiochemical and Biophysical Research Communications
Volume479
Issue number4
DOIs
Publication statusPublished - Oct 28 2016

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All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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