Streptolysin O inhibits clathrin-dependent internalization of group A Streptococcus

Research output: Contribution to journalArticle

Abstract

Group A Streptococcus (GAS) can be internalized by epithelial cells, including keratinocytes from human skin or pharyngeal epithelium. Internalization of GAS by epithelial cells has been postulated both to play a role in host defense and to provide a sanctuary site for GAS survival. The cholesterol-binding cytolysin streptolysin O (SLO) appears to enhance virulence in part by inhibiting GAS internalization by human keratinocytes and by disrupting the lysosomal degradation of internalized GAS. We now report that low-level production of SLO by an inducible expression system reduced GAS internalization by keratinocytes. Induced SLO expression also prevented lysosomal colocalization with intracellular bacteria and acidification of GAS-containing vacuoles. Exogenous recombinant SLO mimicked the inhibitory effect of SLO secretion on GAS entry but not that on colocalization with the lysosomal marker LAMP-1, implying that disruption of lysosomal degradation requires intracellular secretion of SLO. The internalization of SLO-negative GAS was blocked by the depletion of host cell cholesterol and by the inhibition or knocking down of the expression of clathrin or dynamin. SLO also inhibited the cellular uptake of other cargos that are internalized by clathrin-mediated uptake or by macropinocytosis. We conclude that SLO interferes with the internalization of GAS through local perturbation of the keratinocyte cell membrane and disruption of a clathrin-dependent uptake pathway.

Details

Authors
Organisations
External organisations
  • Harvard University
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Infectious Medicine
  • Cell and Molecular Biology

Keywords

  • Bacterial Proteins, Cell Line, Clathrin, Down-Regulation, Dynamins, Gene Expression Regulation, Bacterial, Humans, Keratinocytes, Streptococcal Infections, Streptococcus pyogenes, Streptolysins
Original languageEnglish
Pages (from-to)e00332-10
JournalmBio
Volume2
Issue number1
Publication statusPublished - 2011
Publication categoryResearch
Peer-reviewedYes