STUB1 regulates TFEB-induced autophagy-lysosome pathway

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• Transcription factor EB (TFEB) regulates autophagy and lysosome biogenesis.
• TFEB activity is inhibited by mTOR-mediated phosphorylation.
• Mechanisms controlling TFEB turnover and overall activity remain unclear.

Purpose of the Study:

• To elucidate the mechanisms regulating TFEB activity and turnover.
• To investigate the role of STUB1 in TFEB regulation.
• To understand how the ubiquitin-proteasome pathway influences TFEB function.

Main Methods:

• Cellular overexpression and deficiency models of STUB1.
• Analysis of TFEB phosphorylation and activity.
• Ubiquitination assays and proteasomal degradation studies.
• Studies in STUB1-deficient mice.

Main Results:

• STUB1 targets phosphorylated TFEB for degradation via the ubiquitin-proteasome pathway.
• STUB1 deficiency leads to accumulation of phosphorylated TFEB and reduced TFEB activity.
• STUB1 overexpression reduces phosphorylated TFEB and enhances TFEB activity.
• Reduced TFEB activity in STUB1-deficient cells impairs autophagy and mitochondrial biogenesis.

Conclusions:

• STUB1 acts as a key regulator of TFEB activity by promoting the degradation of phosphorylated TFEB.
• The ubiquitin-proteasome pathway is crucial for controlling TFEB-mediated cellular processes like autophagy and lysosome biogenesis.
• This study uncovers a novel regulatory mechanism for TFEB, impacting cellular homeostasis.