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Updated: Mar 6, 2026

RhoC GTPase Activation Assay
09:58

RhoC GTPase Activation Assay

Published on: August 22, 2010

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The Rho GTPase signaling pathway modulates Moraxella catarrhalis invasion into human respiratory epithelial cells by

Ruirui Ma1,2, Guixue Cheng3, Yun Wu2

  • 1Department of Clinical Laboratory, State Key Laboratory of Complex Severe and Rare Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College Hospital, Beijing, China.

Frontiers in Immunology
|March 5, 2026
PubMed

Insights

Moraxella catarrhalis invasion, a key driver of COPD exacerbations, relies on Rho GTPase regulators. CDC42 and Rac1 are crucial for bacterial entry by controlling actin polymerization and macropinosome formation.

Area of Science:

  • Microbiology
  • Cell Biology
  • Immunology

Background:

  • Moraxella catarrhalis invasion of respiratory cells drives COPD exacerbations.
  • Actin cytoskeleton dynamics are crucial for M. catarrhalis entry, but upstream regulators are unclear.

Purpose of the Study:

  • To identify and validate Rho GTPase regulators involved in M. catarrhalis invasion.
  • To elucidate the molecular mechanisms of M. catarrhalis-induced actin polymerization and host cell entry.

Main Methods:

  • Invasion assays and Transmission Electron Microscopy (TEM) in A549 cells.
  • Utilized wild-type and knockout cell lines for CDC42, Rac1, ArpC2, and ArpC4.
  • Western blot and immunofluorescence to analyze actin dynamics.

Main Results:

  • Rho GTPase signaling regulates M. catarrhalis load by controlling macropinosome volume.
  • CDC42 and Rac1 are essential for actin polymerization and bacterial internalization.
  • ArpC4 influences actin remodeling, ArpC2 is not involved in invasion or actin dynamics.

Conclusions:

  • Rho GTPase signaling pathways are critical for M. catarrhalis invasion by modulating actin polymerization.
  • Findings provide a basis for targeting innate immunity against M. catarrhalis-induced AECOPD.
Keywords:
F-actinG-actinMoraxella catarrhalisRho GTPaseinvasion

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