SIRT1 regulates Dishevelled proteins and promotes transient and constitutive Wnt signaling

Area of Science:

• Molecular Biology
• Cellular Signaling
• Epigenetics

Background:

• Sirtuin 1 (SIRT1) is a histone deacetylase regulating diverse cellular processes.
• Its role in orchestrating pleiotropic effects, including Wnt signaling, remained unclear.
• Previous studies linked SIRT1 to Wnt signaling primarily through epigenetic silencing of antagonists.

Purpose of the Study:

• To investigate the role of Sirtuin 1 (SIRT1) in regulating Wnt signaling.
• To determine if SIRT1 directly impacts key components of the Wnt pathway.
• To elucidate the mechanism by which SIRT1 influences Wnt-mediated cellular functions.

Main Methods:

• Investigated the effect of SIRT1 loss of function on Dishevelled (Dvl) protein levels.
• Performed co-immunoprecipitation to assess in vivo complex formation between SIRT1 and Dvl proteins.
• Analyzed changes in Wnt target gene expression following SIRT1 inhibition.
• Assessed the impact of SIRT1 inhibition on Wnt-stimulated cell migration.

Main Results:

• SIRT1 loss of function significantly decreased levels of all three Dishevelled (Dvl) proteins.
• SIRT1 and Dvl proteins were shown to form complexes in vivo.
• SIRT1 inhibition altered the gene expression of Wnt target genes.
• Wnt-stimulated cell migration was inhibited by a SIRT1 inhibitor.

Conclusions:

• SIRT1 directly regulates Wnt signaling by modulating Dishevelled (Dvl) protein levels.
• This regulation provides a mechanistic link between SIRT1 activity and diverse Wnt-dependent physiological responses.
• SIRT1 acts as a regulator of both transient and constitutive Wnt signaling pathways.