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PARP-1 attenuates Smad-mediated transcription
Peter Lönn1, Lars P van der Heide, Markus Dahl
1Ludwig Institute for Cancer Research, Uppsala University, Box 595 Biomedical Center, SE-751 24 Uppsala, Sweden.
Molecular Cell
|November 25, 2010
Summary
Poly(ADP-ribose) polymerase-1 (PARP-1) interacts with Smad proteins, regulating gene transcription. PARP-1’s ADP-ribosylation of Smad proteins controls transforming growth factor β (TGF-β) signaling duration and strength.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Transforming growth factor β (TGF-β) is a crucial cytokine regulating cellular processes like growth, differentiation, and migration.
- TGF-β signaling involves Smad proteins, which interact with DNA to control gene transcription.
- Smad-mediated transcription is regulated by dephosphorylation, nuclear export, and degradation.
Purpose of the Study:
- To identify novel partners of Smad proteins involved in TGF-β signaling termination.
- To investigate the role of poly(ADP-ribose) polymerase-1 (PARP-1) in Smad-mediated transcription.
Main Methods:
- Unbiased proteomic screening to identify Smad-interacting proteins.
- Biochemical assays to characterize the interaction between PARP-1 and Smad proteins.
- Analysis of Smad-DNA binding and gene transcription in response to TGF-β signaling.
Main Results:
- Poly(ADP-ribose) polymerase-1 (PARP-1) was identified as a Smad-interacting partner.
- PARP-1 ADP-ribosylates Smad3 and Smad4, leading to dissociation of Smad complexes from DNA.
- This interaction attenuates Smad-specific gene responses and TGF-β-induced epithelial-mesenchymal transition.
Conclusions:
- ADP-ribosylation of Smad proteins by PARP-1 is a key mechanism for regulating Smad-mediated transcription.
- PARP-1 acts as a negative regulator of TGF-β signaling by controlling the strength and duration of Smad transcriptional activity.
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