The cytoskeletal network controls c-Jun translation in a UTR-dependent manner

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• The cytoskeleton, a dynamic cellular network, regulates critical processes like proliferation, differentiation, and apoptosis.
• c-Jun, an AP1 transcription factor, is crucial for normal and aberrant cell growth.
• Cytoskeletal dynamics are known to influence cellular events, but their direct impact on c-Jun protein regulation is less understood.

Purpose of the Study:

• To investigate the effect of cytoskeleton depolymerization on c-Jun accumulation.
• To elucidate the regulatory mechanism controlling c-Jun protein levels upon cytoskeletal disruption.
• To determine if changes in c-Jun mRNA or protein stability mediate this accumulation.

Main Methods:

• Depolymerization of actin and microtubule networks in cellular models.
• Quantification of c-Jun protein and mRNA levels.
• Assessment of c-Jun protein half-life.
• Analysis of c-Jun mRNA translatability and the role of untranslated regions (UTRs).

Main Results:

• Depolymerization of the cytoskeleton significantly increased c-Jun protein accumulation.
• This increase occurred without changes in c-Jun mRNA levels or protein half-life.
• The accumulation was attributed to enhanced translation of the c-Jun transcript, mediated by its UTRs.
• The mechanism was independent of activated mitogen-activated protein kinase (MAPK) pathways.

Conclusions:

• Cytoskeleton integrity influences c-Jun protein levels through translational control.
• A novel regulatory mechanism involving c-Jun mRNA UTRs enhances translation upon cytoskeletal disruption.
• This finding provides a new perspective on c-Jun regulation in physiological contexts.