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Internalization of factor J and cellular signalization after factor J-cell interaction
S Larrucea1, R Cambronero, C González-Rubio
1Unidad de Inmunología, Hospital La Paz, Madrid, 28046, Spain.
Biochemical and Biophysical Research Communications
|December 3, 1999
Summary
Factor J (FJ) binds to cells, is internalized, and triggers intracellular signaling. This suggests FJ
Area of Science:
- Immunology and Cell Biology
- Complement System and Signal Transduction
Background:
- Factor J (FJ) is a glycoprotein inhibiting complement activation.
- FJ mediates cell adhesion via the nucleolin receptor.
Purpose of the Study:
- Investigate cellular events following Factor J binding.
- Elucidate the role of FJ in intracellular signal transduction.
Main Methods:
- Cell incubation with Factor J (FJ) in K562 and Jurkat cell lines.
- Analysis of FJ internalization and localization (cytoplasm, nucleus).
- Assessment of tyrosine phosphorylation induced by FJ adhesion, compared to fibronectin (FN).
Main Results:
- Factor J was actively internalized and localized intracellularly.
- Cell adhesion to FJ induced tyrosine phosphorylation of proteins.
- This phosphorylation pattern mimicked fibronectin effects and was inhibited by anti-FJ monoclonal antibody (mAb).
Conclusions:
- Cellular binding of Factor J initiates intracellular biochemical signaling.
- FJ may play a crucial role in signal transduction across the plasma membrane.