Atg8 family proteins, LIR/AIM motifs and other interaction modes

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• The Atg8 protein family, ubiquitin-like modifiers, are central to autophagy, a cellular degradation process.
• They also participate in vesicle fusion and transport, with emerging roles in the nucleus.
• Understanding Atg8 interactions is key to deciphering these diverse cellular functions.

Purpose of the Study:

• To review the structural and functional characteristics of Atg8 family proteins.
• To explore their protein-protein interaction modes across various model organisms and humans.
• To highlight conserved and novel interaction mechanisms, including the LIR-LDS interaction.

Main Methods:

• Literature review of structural and functional studies on Atg8 proteins.
• Comparative analysis of Atg8 homologs and their interaction motifs in diverse species.
• Discussion of emerging methodologies for LIR motif prediction.

Main Results:

• Strong evolutionary conservation of Atg8 structural features and interaction modes, despite varying homolog numbers.
• The LIR-LDS interaction is the most prominent mode, with variants like half-LIRs and helical LIRs.
• Phosphorylation regulates some LIR-LDS interactions, and novel interaction surfaces (N-terminal arm, UDS) are being identified.

Conclusions:

• Atg8 proteins utilize conserved interaction mechanisms, primarily LIR-LDS binding, for selective autophagy.
• Understanding these interactions, including regulatory mechanisms and novel surfaces, is vital for advancing autophagy research.
• Future studies will likely uncover additional Atg8 interaction modes and functions.