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Regulation of mammalian autophagy by class II and III PI 3-kinases through PI3P synthesis.

Publication ,  Journal Article
Devereaux, K; Dall'Armi, C; Alcazar-Roman, A; Ogasawara, Y; Zhou, X; Wang, F; Yamamoto, A; De Camilli, P; Di Paolo, G
Published in: PLoS One
2013

Synthesis of phosphatidylinositol-3-phosphate (PI3P) by Vps34, a class III phosphatidylinositol 3-kinase (PI3K), is critical for the initial steps of autophagosome (AP) biogenesis. Although Vps34 is the sole source of PI3P in budding yeast, mammalian cells can produce PI3P through alternate pathways, including direct synthesis by the class II PI3Ks; however, the physiological relevance of these alternate pathways in the context of autophagy is unknown. Here we generated Vps34 knockout mouse embryonic fibroblasts (MEFs) and using a higher affinity 4x-FYVE finger PI3P-binding probe found a Vps34-independent pool of PI3P accounting for (~)35% of the total amount of this lipid species by biochemical analysis. Importantly, WIPI-1, an autophagy-relevant PI3P probe, still formed some puncta upon starvation-induced autophagy in Vps34 knockout MEFs. Additional characterization of autophagy by electron microscopy as well as protein degradation assays showed that while Vps34 is important for starvation-induced autophagy there is a significant component of functional autophagy occurring in the absence of Vps34. Given these findings, class II PI3Ks (α and β isoforms) were examined as potential positive regulators of autophagy. Depletion of class II PI3Ks reduced recruitment of WIPI-1 and LC3 to AP nucleation sites and caused an accumulation of the autophagy substrate, p62, which was exacerbated upon the concomitant ablation of Vps34. Our studies indicate that while Vps34 is the main PI3P source during autophagy, class II PI3Ks also significantly contribute to PI3P generation and regulate AP biogenesis.

Duke Scholars

Published In

PLoS One

DOI

EISSN

1932-6203

Publication Date

2013

Volume

8

Issue

10

Start / End Page

e76405

Location

United States

Related Subject Headings

  • Proteolysis
  • Protein Phosphatase 2C
  • Protein Binding
  • Phosphoprotein Phosphatases
  • Phosphatidylinositol Phosphates
  • Phagosomes
  • Mice, Knockout
  • Mice
  • Lysosomes
  • Intracellular Space
 

Citation

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Devereaux, K., Dall’Armi, C., Alcazar-Roman, A., Ogasawara, Y., Zhou, X., Wang, F., … Di Paolo, G. (2013). Regulation of mammalian autophagy by class II and III PI 3-kinases through PI3P synthesis. PLoS One, 8(10), e76405. https://doi.org/10.1371/journal.pone.0076405
Devereaux, Kelly, Claudia Dall’Armi, Abel Alcazar-Roman, Yuta Ogasawara, Xiang Zhou, Fan Wang, Akitsugu Yamamoto, Pietro De Camilli, and Gilbert Di Paolo. “Regulation of mammalian autophagy by class II and III PI 3-kinases through PI3P synthesis.PLoS One 8, no. 10 (2013): e76405. https://doi.org/10.1371/journal.pone.0076405.
Devereaux K, Dall’Armi C, Alcazar-Roman A, Ogasawara Y, Zhou X, Wang F, et al. Regulation of mammalian autophagy by class II and III PI 3-kinases through PI3P synthesis. PLoS One. 2013;8(10):e76405.
Devereaux, Kelly, et al. “Regulation of mammalian autophagy by class II and III PI 3-kinases through PI3P synthesis.PLoS One, vol. 8, no. 10, 2013, p. e76405. Pubmed, doi:10.1371/journal.pone.0076405.
Devereaux K, Dall’Armi C, Alcazar-Roman A, Ogasawara Y, Zhou X, Wang F, Yamamoto A, De Camilli P, Di Paolo G. Regulation of mammalian autophagy by class II and III PI 3-kinases through PI3P synthesis. PLoS One. 2013;8(10):e76405.

Published In

PLoS One

DOI

EISSN

1932-6203

Publication Date

2013

Volume

8

Issue

10

Start / End Page

e76405

Location

United States

Related Subject Headings

  • Proteolysis
  • Protein Phosphatase 2C
  • Protein Binding
  • Phosphoprotein Phosphatases
  • Phosphatidylinositol Phosphates
  • Phagosomes
  • Mice, Knockout
  • Mice
  • Lysosomes
  • Intracellular Space