Rab39a interacts with phosphatidylinositol 3-kinase and negatively regulates autophagy induced by lipopolysaccharide stimulation in macrophages

Shintaro Seto; Keiko Sugaya; Kunio Tsujimura; Toshi Nagata; Toshinobu Horii; Yukio Koide

doi:10.1371/journal.pone.0083324

Rab39a interacts with phosphatidylinositol 3-kinase and negatively regulates autophagy induced by lipopolysaccharide stimulation in macrophages

PLoS One. 2013 Dec 13;8(12):e83324. doi: 10.1371/journal.pone.0083324. eCollection 2013.

Authors

Shintaro Seto¹, Keiko Sugaya², Kunio Tsujimura¹, Toshi Nagata², Toshinobu Horii¹, Yukio Koide³

Affiliations

¹ Department of Infectious Diseases, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan.
² Department of Health Science, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan.
³ Department of Infectious Diseases, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan ; Executive Director, Hamamatsu University School of Medicine, Hamamatsu Hamamatsu, Shizuoka, Japan.

Abstract

Rab39a has pleiotropic functions in phagosome maturation, inflammatory activation and neuritogenesis. Here, we characterized Rab39a function in membrane trafficking of phagocytosis and autophagy induction in macrophages. Rab39a localized to the periphery of LAMP2-positive vesicles and showed the similar kinetics on the phagosome to that of LAMP1. The depletion of Rab39a did not influence the localization of LAMP2 to the phagosome, but it augments the autophagosome formation and LC3 processing by lipopolysaccharide (LPS) stimulation. The augmentation of autophagosome formation in Rab39a-knockdown macrophages was suppressed by Atg5 depletion or an inhibitor for phosphatidylinostol 3-kinase (PI3K). Immunoprecipitation analysis revealed that Rab39a interacts with PI3K and that the amino acid residues from 34(th) to 41(st) in Rab39a were indispensable for this interaction. These results suggest that Rab39a negatively regulates the LPS-induced autophagy in macrophages.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Autophagy / drug effects*
Autophagy / physiology
Cell Line
Humans
Lipopolysaccharides / pharmacology*
Lysosomal Membrane Proteins / genetics
Lysosomal Membrane Proteins / metabolism
Macrophages / cytology
Macrophages / metabolism*
Mice
Mice, Knockout
Phosphatidylinositol 3-Kinases / genetics
Phosphatidylinositol 3-Kinases / metabolism*
Protein Binding / drug effects
Protein Binding / physiology
rab GTP-Binding Proteins / genetics
rab GTP-Binding Proteins / metabolism*

Substances

Lamp1 protein, mouse
Lipopolysaccharides
Lysosomal Membrane Proteins
Phosphatidylinositol 3-Kinases
Rab39A protein, mouse
rab GTP-Binding Proteins

Grants and funding

This work was supported in part by Grants-in-Aid for Young Scientists (B) from the Japan Society for the Promotion of Science; the Health and Labour Science Research Grants for Research into Emerging and Reemerging Infectious Diseases from the Ministry of Health, Labour and Welfare of Japan; and the United States-Japan Cooperative Medical Science Committee. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.