RAB30 regulates PI4KB (phosphatidylinositol 4-kinase beta)-dependent autophagy against group A Streptococcus

Autophagy. 2019 Mar;15(3):466-477. doi: 10.1080/15548627.2018.1532260. Epub 2018 Oct 18.

Abstract

Macroautophagy/autophagy plays an important role in the immune response to invasion by intracellular pathogens such as group A Streptococcus (GAS; Streptococcus pyogenes). We previously identified RAB30, a Golgi-resident GTPase, as a novel anti-bacterial autophagic regulator in the formation of GAS-containing autophagosome-like vacuoles (GcAVs); however, the precise mechanism underlying this process remains elusive. Here, we elucidate a novel property of RAB30: the ability to recruit PI4KB (phosphatidylinositol 4-kinase beta) to the Golgi apparatus and GcAVs. We found that trans-Golgi network (TGN) vesicles were incorporated into GcAVs via RAB30 to promote GcAV formation. Moreover, depletion of phosphatidylinositol-4-phosphate (PtdIns4P), a phosphatidylinositol enriched in the TGN, by wortmannin and phenylarsine oxide, followed by subsequent repletion with exogenous PtdIns4P revealed that PtdIns4P is crucial for GcAV formation. Furthermore, we identify an interaction between RAB30 and PI4KB, in which the knockdown of RAB30 decreased the localization of PI4KB to the TGN and GcAVs. Finally, PI4KB knockout suppressed autophagy by inhibiting GcAV formation, resulting in the increased survival of GAS. Our results demonstrate a novel autophagosomal formation mechanism involving coordinative functions of RAB30 and PI4KB distinct from those utilized in canonical autophagy. Abbreviations: GAS: group A Streptococcus; GcAVs: GAS-containing autophagosome-like vacuoles; PI4KB: phosphatidylinositol 4-kinase beta; PtdIns: phosphatidylinositol; PtdIns3P: phosphatidylinositol-3-phosphate; PtdIns4P: phosphatidylinositol-4-phosphate; PtdIns5P: phosphatidylinositol-5-phosphate; SLO: streptolysin O; TGN: trans-Golgi network; TGOLN2: trans-golgi network protein 2; PH: plekstrin homology; OSBP: oxysterol binding protein.

Keywords: GcAV; PI4KB; group A; trans-Golgi network; xenophagy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 1-Phosphatidylinositol 4-Kinase / antagonists & inhibitors
  • 1-Phosphatidylinositol 4-Kinase / genetics
  • 1-Phosphatidylinositol 4-Kinase / metabolism*
  • Autophagosomes / metabolism
  • Autophagosomes / microbiology*
  • Autophagy / genetics
  • Golgi Apparatus / metabolism*
  • Golgi Apparatus / microbiology
  • HEK293 Cells
  • HeLa Cells
  • Host-Pathogen Interactions
  • Humans
  • Phosphatidylinositol Phosphates / chemistry
  • Phosphatidylinositol Phosphates / metabolism
  • Phosphorylation
  • Streptococcus pyogenes / physiology*
  • Vacuoles / metabolism
  • Vacuoles / microbiology
  • rab GTP-Binding Proteins / antagonists & inhibitors
  • rab GTP-Binding Proteins / genetics
  • rab GTP-Binding Proteins / metabolism*
  • trans-Golgi Network / metabolism*
  • trans-Golgi Network / microbiology

Substances

  • Phosphatidylinositol Phosphates
  • phosphatidylinositol 4-phosphate
  • 1-Phosphatidylinositol 4-Kinase
  • RAB30 protein, human
  • rab GTP-Binding Proteins

Grants and funding

This research was supported in part by Grants-in-Aid for Scientific Research (16H05188, 15K15130, 26462776, 17K19552), the Takeda Science Foundation (T.N.), Yakult Bio-Science Foundation, Joint Research Project of the Institute of Medical Science, the University of Tokyo (I.N.), the Research Program on Emerging and Re-emerging Infectious Diseases (18fk0108044h0202, 18fk0108073h0001) and J-PRIDE (18fm0208030h0002) from Japan Agency for Medical Research and development, AMED (I.N.).