Interaction of Leptospira elongation factor Tu with plasminogen and complement factor H: a metabolic leptospiral protein with moonlighting activities

PLoS One. 2013 Nov 27;8(11):e81818. doi: 10.1371/journal.pone.0081818. eCollection 2013.

Abstract

The elongation factor Tu (EF-Tu), an abundant bacterial protein involved in protein synthesis, has been shown to display moonlighting activities. Known to perform more than one function at different times or in different places, it is found in several subcellular locations in a single organism, and may serve as a virulence factor in a range of important human pathogens. Here we demonstrate that Leptospira EF-Tu is surface-exposed and performs additional roles as a cell-surface receptor for host plasma proteins. It binds plasminogen in a dose-dependent manner, and lysine residues are critical for this interaction. Bound plasminogen is converted to active plasmin, which, in turn, is able to cleave the natural substrates C3b and fibrinogen. Leptospira EF-Tu also acquires the complement regulator Factor H (FH). FH bound to immobilized EF-Tu displays cofactor activity, mediating C3b degradation by Factor I (FI). In this manner, EF-Tu may contribute to leptospiral tissue invasion and complement inactivation. To our knowledge, this is the first description of a leptospiral protein exhibiting moonlighting activities.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blood Coagulation
  • Complement Factor H / metabolism*
  • Fibrinolysin / metabolism
  • Host-Pathogen Interactions
  • Immune Evasion
  • Immunity, Innate / immunology
  • Leptospira / enzymology*
  • Leptospira / metabolism
  • Leptospira / physiology
  • Lysine / metabolism
  • Peptide Elongation Factor Tu / chemistry
  • Peptide Elongation Factor Tu / metabolism*
  • Plasminogen / metabolism*
  • Protein Binding
  • Protein Transport

Substances

  • Complement Factor H
  • Plasminogen
  • Fibrinolysin
  • Peptide Elongation Factor Tu
  • Lysine

Grants and funding

Fundação de Amparo à Pesquisa do Estado de São Paulo (grants 2011/07297-3 and 2010/50043-0). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.