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Assessing the Cellular Immune Response of the Fruit Fly, Drosophila melanogaster, Using an In Vivo Phagocytosis Assay
05:50

Assessing the Cellular Immune Response of the Fruit Fly, Drosophila melanogaster, Using an In Vivo Phagocytosis Assay

Published on: April 10, 2019

Endocytic pathway is required for Drosophila Toll innate immune signaling

Hon-Ren Huang1, Zhijian J Chen, Sam Kunes

  • 1Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.

Proceedings of the National Academy of Sciences of the United States of America
|April 21, 2010
PubMed

Insights

The Toll signaling pathway, crucial for innate immunity, requires endosomal proteins Myopic (Mop) and Hepatocyte growth factor-regulated tyrosine kinase substrate (Hrs) for activation. This study reveals endocytosis is essential for Toll pathway signaling in Drosophila.

Area of Science:

  • Immunology
  • Cell Biology
  • Molecular Biology

Background:

  • The Toll signaling pathway is vital for Drosophila's innate immune response against fungal and Gram-positive bacterial infections.
  • Understanding the molecular mechanisms regulating Toll pathway activation is crucial for comprehending innate immunity.

Purpose of the Study:

  • To investigate the role of endosomal proteins Myopic (Mop) and Hepatocyte growth factor-regulated tyrosine kinase substrate (Hrs) in Toll signaling pathway activation.
  • To determine the precise localization and function of Mop and Hrs within the Toll pathway.

Main Methods:

  • Utilized cultured Drosophila cells and whole flies to study Toll pathway activation.
  • Performed epistasis experiments to establish the order of protein function in the pathway.
  • Employed colocalization studies to examine the interaction of Mop and Hrs with the Toll receptor.

Main Results:

  • Demonstrated that both Mop and Hrs are essential for the activation of the Toll signaling pathway.
  • Epistasis experiments revealed that Mop functions upstream of key signaling components MyD88 and Pelle kinase.
  • Showed that Mop and Hrs, components of the ESCRT-0 complex, colocalize with the Toll receptor in endosomes.

Conclusions:

  • Endocytosis is a critical process required for the activation of the Toll signaling pathway in Drosophila.
  • The endosomal proteins Mop and Hrs play a significant role in initiating Toll pathway signaling, likely by facilitating receptor localization or function within endosomes.

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