Acetylation of RNA processing proteins and cell cycle proteins in mitosis

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• Mitosis is a critical cell division process where transcription and translation are suppressed.
• Post-translational modifications like phosphorylation and ubiquitination regulate mitosis.
• Genomic instability, a cancer hallmark, can arise from errors during mitosis.

Purpose of the Study:

• To investigate the prevalence and role of protein acetylation during mitosis.
• To identify specific proteins that undergo acetylation during this phase.
• To explore the functional consequences of protein acetylation and deacetylation in mitosis.

Main Methods:

• Synchronizing HeLa cells in early prometaphase.
• Immunoprecipitation of lysine-acetylated proteins using anti-acetyl-lysine antibody.
• Mass spectrometry (LC-ESI-MS/MS) for protein identification.
• Western blot analysis to confirm acetylation of specific proteins.
• Treatment with histone deacetylase inhibitors (apicidin, trichostatin A).

Main Results:

• Identified numerous proteins acetylated during mitosis, including those involved in RNA processing, cell cycle regulation, and DNA repair.
• Confirmed acetylation of RNA processing proteins (eIF4G, RNA helicase A) and cell cycle proteins (APC1, anillin, NudC).
• Demonstrated that apicidin treatment enhanced APC1 and NudC acetylation, implicating histone deacetylases.
• Observed spindle abnormalities and cytokinesis failure upon treatment with apicidin or trichostatin A.

Conclusions:

• Protein acetylation is a widespread post-translational modification during mitosis.
• Acetylation regulates key proteins involved in RNA processing and cell cycle control.
• Histone deacetylase activity influences mitotic protein acetylation.
• Aberrant acetylation/deacetylation disrupts mitotic progression, leading to genomic instability and potential cancer development.