HTRA1-Dependent Cell Cycle Proteomics.

Area of Science:

• Molecular Biology
• Proteomics
• Cell Biology

Background:

• The HTRA1 gene encodes a protein quality-control factor crucial for cellular function.
• HTRA1 dysfunction, via epigenetic silencing or mutation, is linked to pathologies like cancer and aberrant cell phenotypes.
• Loss of HTRA1 function is associated with accelerated cell growth, delayed senescence, centrosome amplification, and polyploidy, suggesting a role in cell cycle regulation.

Purpose of the Study:

• To investigate the role of HTRA1 in regulating protein abundance across different cell cycle phases.
• To correlate protein expression levels with HTRA1 abundance during the cell cycle using large-scale proteomics.

Main Methods:

• Utilized label-free-quantification mass spectrometry for a large-scale proteomics study.
• Correlated protein abundance with HTRA1 levels across various cell cycle phases.
• Employed pull-down assays to validate protein interactions and functional implications.

Main Results:

• Identified 4723 proteins with cell-cycle-dependent fluctuations.
• Found 2872 proteins affected by HTRA1 levels, with 1530 showing both cell-cycle and HTRA1 dependency.
• Demonstrated HTRA1's broad impact on protein homeostasis and its involvement in DNA replication, chromosome segregation, and apoptosis.

Conclusions:

• The extensive number of affected proteins underscores HTRA1's general role in maintaining protein homeostasis.
• HTRA1 significantly influences key cell cycle events, including DNA replication, chromosome segregation, and programmed cell death.
• These findings highlight the broad implications of HTRA1 in fundamental cellular physiology and disease processes.