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Immunofluorescence Staining Using IBA1 and TMEM119 for Microglial Density, Morphology and Peripheral Myeloid Cell Infiltration Analysis in Mouse Brain
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Microglia/macrophage-specific protein Iba1 binds to fimbrin and enhances its actin-bundling activity

Keiko Ohsawa1, Yoshinori Imai, Yo Sasaki

  • 1Department of Neurochemistry, National Institute of Neuroscience, Tokyo, Japan. kohsaka@ncnp.go.jp

Journal of Neurochemistry
|February 6, 2004
PubMed

Insights

Ionized calcium binding adaptor molecule 1 (Iba1) interacts with L-fimbrin, another actin-bundling protein. This interaction enhances L-fimbrin

Area of Science:

  • Cell Biology
  • Immunology
  • Molecular Biology

Background:

  • Ionized calcium binding adaptor molecule 1 (Iba1) is a microglia/macrophage-specific protein involved in actin reorganization.
  • Iba1 plays a role in membrane ruffling and phagocytosis in activated microglia.

Purpose of the Study:

  • To elucidate the intracellular signaling pathway associated with Iba1.
  • To identify molecules that interact with Iba1.

Main Methods:

  • Yeast two-hybrid screen to identify Iba1-interacting proteins.
  • Co-localization studies in MG5 microglial cell line.
  • Biochemical assays including immunoprecipitation, glutathione S-transferase pull-down, and ligand overlay assays using purified proteins.

Main Results:

  • L-fimbrin, an actin-bundling protein, was identified as an Iba1-interacting molecule.
  • L-fimbrin and Iba1 co-localized in membrane ruffles and phagocytic cups upon stimulation.
  • Direct binding between Iba1 and L-fimbrin was confirmed, and Iba1 binding enhanced L-fimbrin's actin-bundling activity.

Conclusions:

  • Iba1 forms complexes with L-fimbrin in cellular structures crucial for microglial function.
  • The Iba1-L-fimbrin interaction modulates actin reorganization, facilitating microglial cell migration and phagocytosis.

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