Oxidized Phagosomal NOX2 Complex Is Replenished From Lysosomes

J Cell Sci. 2017 Apr 1;130(7):1285-1298. doi: 10.1242/jcs.196931. Epub 2017 Feb 15.

Abstract

In dendritic cells, the NADPH oxidase 2 complex (NOX2) is recruited to the phagosomal membrane during antigen uptake. NOX2 produces reactive oxygen species (ROS) in the lumen of the phagosome that kill ingested pathogens, delay antigen breakdown and alter the peptide repertoire for presentation to T cells. How the integral membrane component of NOX2, cytochrome b558 (which comprises CYBB and CYBA), traffics to phagosomes is incompletely understood. In this study, we show in dendritic cells derived from human blood-isolated monocytes that cytochrome b558 is initially recruited to the phagosome from the plasma membrane during phagosome formation. Cytochrome b558 also traffics from a lysosomal pool to phagosomes and this is required to replenish oxidatively damaged NOX2. We identified syntaxin-7, SNAP23 and VAMP8 as the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins mediating this process. Our data describe a key mechanism of how dendritic cells sustain ROS production after antigen uptake that is required to initiate T cell responses.

Keywords: Dendritic cell; NOX2; Phagocytosis; Phagosome maturation; Reactive oxygen species; SNARE.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Compartmentation
  • Cell Membrane / metabolism
  • Cytochrome b Group / metabolism
  • Endosomes / metabolism
  • Gene Knockdown Techniques
  • Humans
  • Intracellular Membranes / metabolism
  • Lysosomal-Associated Membrane Protein 1 / metabolism
  • Lysosomes / metabolism*
  • Membrane Glycoproteins / metabolism*
  • Models, Biological
  • NADPH Oxidase 2
  • NADPH Oxidases / metabolism*
  • Oxidation-Reduction
  • Phagosomes / metabolism*
  • Phosphatidylinositols / metabolism
  • Qa-SNARE Proteins
  • Qb-SNARE Proteins / metabolism
  • Qc-SNARE Proteins / metabolism
  • R-SNARE Proteins / metabolism
  • RNA, Small Interfering / metabolism
  • Reactive Oxygen Species / metabolism
  • Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins / metabolism

Substances

  • Cytochrome b Group
  • Lysosomal-Associated Membrane Protein 1
  • Membrane Glycoproteins
  • Phosphatidylinositols
  • Qa-SNARE Proteins
  • Qb-SNARE Proteins
  • Qc-SNARE Proteins
  • R-SNARE Proteins
  • RNA, Small Interfering
  • Reactive Oxygen Species
  • SNAP23 protein, human
  • Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins
  • VAMP8 protein, human
  • cytochrome b558
  • CYBB protein, human
  • NADPH Oxidase 2
  • NADPH Oxidases