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Legionella pneumophila secretes a mitochondrial carrier protein during infection

Pavel Dolezal1, Margareta Aili, Janette Tong

  • 1Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia.

Plos Pathogens
|January 14, 2012
PubMed

Insights

Researchers discovered a novel bacterial protein, Legionella nucleotide carrier protein (LncP), that transports ATP across mitochondrial membranes. This finding challenges the exclusive eukaryotic origin of mitochondrial carrier family proteins.

Area of Science:

  • Molecular biology
  • Microbiology
  • Biochemistry

Background:

  • Mitochondrial Carrier Family (MCF) proteins are essential eukaryotic integral membrane proteins.
  • MCF proteins facilitate metabolite transport across the mitochondrial inner membrane via six transmembrane segments.
  • These proteins form selective channels for crucial cellular transport processes.

Purpose of the Study:

  • To identify and characterize novel members of the Mitochondrial Carrier Family (MCF).
  • To investigate the function and localization of a newly discovered bacterial MCF protein, Legionella nucleotide carrier protein (LncP).
  • To explore the presence of MCF proteins in intracellular pathogens beyond eukaryotes.

Main Methods:

  • Genomic analysis to identify novel MCF candidates.
  • Expression and localization studies of LncP in a yeast model system.
  • Liposome reconstitution and transport assays to determine LncP's substrate specificity.
  • Hidden Markov model analysis for identifying homologous proteins.

Main Results:

  • A novel MCF member, LncP, was identified in Legionella pneumophila.
  • LncP was secreted into host macrophages and localized to the mitochondrial inner membrane.
  • LncP functions as an ATP transporter, catalyzing unidirectional ATP transport and exchange.
  • Homologous MCF proteins were found in Legionella longbeachae and Neorickettsia sennetsu.

Conclusions:

  • Legionella nucleotide carrier protein (LncP) is a functional bacterial ATP transporter.
  • The discovery of LncP in bacteria challenges the established view of MCF proteins as exclusively eukaryotic.
  • MCF proteins are present in intracellular pathogens, suggesting broader roles in host-pathogen interactions.

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