Tagged ATG8-Coding Constructs for the In Vitro and In Vivo Assessment of ATG4 Activity.

Area of Science:

• Cell Biology
• Molecular Biology
• Evolutionary Biology

Background:

• Autophagy is a vital cellular process for degrading cytoplasmic components, involving over 30 genes in yeast.
• The Atg4-Atg8 proteolytic system, crucial for autophagy, has evolved in complexity from single proteases/substrates in yeast to multiple members in multicellular organisms.
• Human cells possess four Atg4 proteases and six Atg8 substrates, suggesting specialized roles in complex autophagic pathways.

Purpose of the Study:

• To investigate the reasons behind the evolutionary complexity of the Atg4-Atg8 proteolytic system.
• To present a technique for analyzing protease-substrate specificity within this system in mammalian cells.
• To enable the assessment of cellular efficiency in the initial cleavage of Atg8 family members.

Main Methods:

• Development and application of a technique to analyze protease-substrate specificity.
• Utilizing the technique in diverse experimental settings.
• Testing the method in both cultured mammalian cells and live laboratory mice.

Main Results:

• The study describes two applications of a novel technique for analyzing the Atg4-Atg8 system.
• The technique allows for the determination of cellular efficiency in the initial cleavage of Atg8 family members.
• The method is applicable across various experimental conditions, including in vivo studies.

Conclusions:

• The presented technique offers a simple yet effective way to study protease-substrate specificity in the mammalian Atg4-Atg8 system.
• This research contributes to understanding the functional diversification of autophagy components during evolution.
• The findings facilitate further investigation into the regulation of autophagy in complex biological systems.