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Type IV secretion in the obligatory intracellular bacterium Anaplasma phagocytophilum

Yasuko Rikihisa1, Mingqun Lin, Hua Niu

  • 1Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA. rikihisa.1@osu.edu

Cellular Microbiology
|July 31, 2010
PubMed

Insights

Anaplasma phagocytophilum uses a type IV secretion system to inject effector proteins into host cells, aiding its survival and manipulation of host defenses during infection. This mechanism is crucial for the bacterium

Area of Science:

  • Microbiology
  • Cellular Biology
  • Pathogen-Host Interactions

Background:

  • Anaplasma phagocytophilum is an intracellular bacterium causing human granulocytic anaplasmosis.
  • The bacterium infects neutrophils, critical host defense cells.
  • Despite genome reduction, Anaplasma has expanded its type IV secretion (T4S) system genes.

Purpose of the Study:

  • To investigate the role of the T4S system and its effector proteins in Anaplasma phagocytophilum pathogenesis.
  • To understand how Anaplasma manipulates host cells for survival and replication.

Main Methods:

  • Analysis of Anaplasma phagocytophilum genome evolution, focusing on T4S apparatus genes.
  • Identification and characterization of T4S effector proteins, Ats-1 and AnkA.
  • Investigation of effector protein secretion, localization, and function within host cells.

Main Results:

  • Anaplasma phagocytophilum possesses an expanded T4S system, crucial for pathogenesis.
  • Two effector proteins, Ats-1 and AnkA, are secreted into the host cytoplasm.
  • These effectors possess eukaryotic motifs, manipulate host cell processes, and exhibit distinct subcellular localizations.

Conclusions:

  • The T4S system is a key survival factor for Anaplasma phagocytophilum, enabling host cell manipulation.
  • Effector proteins Ats-1 and AnkA play distinct roles in subverting host cell functions.
  • Understanding these mechanisms provides insights into treating anaplasmosis.

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