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YopK regulates the Yersinia pestis type III secretion system from within host cells

Rebecca Dewoody1, Peter M Merritt, Andrew S Houppert

  • 1Department of Biology, Indiana University, Bloomington, IN 47405, USA.

Molecular Microbiology
|January 6, 2011
PubMed

Insights

Yersinia

Area of Science:

  • Microbiology
  • Cell Biology
  • Bacterial Pathogenesis

Background:

  • Pathogenic Yersinia species utilize a type III secretion system (T T S S) to inject cytotoxic effectors (Yops) into host cells.
  • YopK (also known as YopQ) is a key regulator of Yop injection across Yersinia species.
  • YopK exhibits paradoxical behavior: yopK mutants show increased Yop injection and cytotoxicity in vitro but are attenuated in vivo.

Purpose of the Study:

  • To elucidate the mechanism underlying the paradoxical in vitro and in vivo roles of YopK in Yersinia pathogenesis.
  • To investigate how YopK regulates the translocation of Yop effectors into host cells.
  • To determine the relationship between YopK and YopE in regulating the T T S S.

Main Methods:

  • Utilized a beta-lactamase reporter assay to quantify Yop translocation rates.
  • Investigated YopK's regulatory function from both bacterial and host cell compartments.
  • Examined the interplay between YopK and YopE in the context of Yop injection.

Main Results:

  • YopK directly controls the rate of Yop effector injection into host cells.
  • YopK's regulatory activity on Yop translocation does not originate from within the bacterial cytosol.
  • YopK and YopE regulate Yop injection at distinct steps, with YopK functioning independently of YopE.
  • Host cell-expressed YopK confers resistance to Yop injection, indicating YopK regulates translocation from within the host cell.

Conclusions:

  • YopK plays a critical role in modulating the Yersinia T T S S, acting independently of YopE.
  • YopK's function in regulating Yop injection is dependent on its location, suggesting a novel mechanism of control from within the host cell.
  • These findings offer new insights into the complex regulatory network governing bacterial effector delivery during infection.

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