Inducin Triggers LC3-Lipidation and ESCRT-Mediated Lysosomal Membrane Repair

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• LC3 lipidation is a common marker for autophagy.
• However, LC3 lipidation can also occur independently of canonical autophagy.
• Understanding the triggers for LC3 lipidation is vital for elucidating LC3's biological functions.

Purpose of the Study:

• To identify novel compounds that modulate LC3 lipidation.
• To investigate the mechanisms by which LC3 lipidation is regulated.
• To explore the cellular consequences of non-canonical LC3 lipidation.

Main Methods:

• High-throughput screening for compounds affecting LC3 lipidation.
• Biochemical assays to assess lysosomal function.
• Immunofluorescence microscopy to track protein localization.
• Genetic manipulation to study ESCRT and TFEB pathways.

Main Results:

• A pseudo-natural product, Inducin, was identified.
• Inducin induces LC3 lipidation independently of canonical autophagy.
• Inducin impairs lysosomal function and recruits Galectin 3 to lysosomes.
• Inducin promotes ESCRT-dependent membrane repair and TFEB-dependent lysosome biogenesis.
• Inducin treatment leads to cell death.

Conclusions:

• LC3 lipidation can be modulated by non-autophagic stimuli.
• Inducin provides a novel tool to study LC3 lipidation.
• Inducin's effects involve lysosomal dysfunction, membrane repair, and lysosome biogenesis.
• Inducin-induced cellular events culminate in cell death.