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Pellino2 activates the mitogen activated protein kinase pathway.
Liselotte E Jensen1, Alexander S Whitehead
1Department of Pharmacology and Center for Pharmacogenetics, University of Pennsylvania School of Medicine, 153 Johnson Pavilion, 3620 Hamilton Walk, Philadelphia, PA 19104-6084, USA. jensen@pharm.med.upenn.edu
FEBS Letters
|June 14, 2003
Summary
The study reveals Pellino proteins act as crucial scaffolds in innate immune signaling. Pellino2 specifically interacts with TRAF6 and TAK1, activating pathways that regulate transcription factors like AP-1.
Area of Science:
- Immunology
- Molecular Biology
- Cell Signaling
Background:
- Interleukin-1 (IL1) and Toll receptors are key components of the innate immune system.
- Activation of transcription factors NF-kappaB, Elk-1, and AP-1 is facilitated by these receptors.
- Pellino1 and Pellino2 are known intermediates in NF-kappaB activation pathways.
Purpose of the Study:
- To investigate the interaction of Pellino proteins with TRAF6 and TAK1.
- To determine the role of Pellino1 and Pellino2 in IL1/Toll signaling cascades.
- To elucidate the function of Pellino proteins as potential scaffold proteins regulating signaling pathways.
Main Methods:
- Co-immunoprecipitation assays to demonstrate protein interactions.
- Western blotting to detect protein expression and activation.
- Reporter gene assays to assess transcription factor activity.
Main Results:
- Human Pellino2 was shown to interact with TRAF6 (tumor necrosis factor receptor associated factor 6).
- Both Pellino1 and Pellino2 were found to interact with TAK1 (transforming growth factor-beta activated kinase 1).
- Pellino2, but not Pellino1, activated the mitogen-activated protein kinase pathway, leading to AP-1 and Elk-1 activation.
Conclusions:
- Pellino proteins function as scaffold proteins within IL1/Toll signaling pathways.
- Pellino2 plays a distinct role in activating the MAPK pathway and subsequent transcription factor activity.
- These findings suggest Pellino proteins are critical regulators at signaling branch-points in innate immunity.