Cells Lacking PA200 Adapt to Mitochondrial Dysfunction by Enhancing Glycolysis via Distinct Opa1 Processing

Area of Science:

• Cell Biology
• Molecular Biology
• Neuroscience

Background:

• The conserved Blm10/PA200 proteins function as proteasome activators.
• Previous studies identified PA200-enriched genomic regions and its redistribution upon mitochondrial inhibition.
• PA200 was implicated in regulating cellular homeostasis at the transcriptional level.

Purpose of the Study:

• To investigate the impact of stable PA200 depletion (shPA200) on the transcriptome of SH-SY5Y neuroblastoma cells.
• To determine how PA200 deficiency affects cellular metabolism and mitochondrial function.
• To explore the role of PA200 in response to ATP synthase inhibition.

Main Methods:

• RNA-sequencing (RNA-seq) for transcriptome analysis.
• Metabolic assays in live cells to assess respiration and glycolysis.
• Mitochondrial morphology assessment.
• Western blotting to analyze protein levels (Opa1, OMA1).

Main Results:

• PA200 depletion caused significant changes in the transcriptional landscape, affecting genes involved in metabolism.
• While basal respiration remained unchanged, spare respiratory capacity and proton leak were reduced in shPA200 cells.
• Glycolysis and glycolytic capacity increased in PA200-deficient cells, suggesting a metabolic shift.
• Oligomycin-induced stress revealed preserved mitochondrial morphology and reduced OMA1 levels in shPA200 cells.
• Proteolytic cleavage of Opa1 was affected in PA200-depleted cells.

Conclusions:

• PA200 plays a role in regulating metabolic processes, including glycolysis and mitochondrial function.
• PA200 deficiency promotes a shift towards glycolysis, particularly under metabolic stress.
• PA200 influences mitochondrial dynamics and protein processing (Opa1 cleavage) in response to ATP synthase inhibition.