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Author Spotlight: Imaging ATG9A, a Multi-Spanning Membrane Protein
Published on: June 16, 2023
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Atg23 is a vesicle-tethering protein.
Kelsie A Leary1, Wayne D Hawkins2,3, Devika Andhare1
1Department of Chemistry, Dartmouth College, Hanover, NH, USA.
Autophagy
|July 22, 2022
Summary
Atg23, a protein essential for autophagy in yeast, functions as a dimer to bind and tether membranes. Monomeric Atg23 disrupts vesicle trafficking and blocks key cellular pathways.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Autophagy is a crucial cellular process for recycling damaged components.
- In yeast, Atg9-containing vesicles are the initial membrane source for autophagy.
- The precise function of Atg23, an Atg9-binding protein, in vesicle trafficking remains unclear.
Purpose of the Study:
- To elucidate the molecular function of Atg23 in yeast autophagy.
- To investigate the structural and functional properties of Atg23.
- To determine the role of Atg23 dimerization in its cellular activity.
Main Methods:
- Cellular biology techniques to study Atg23 localization and function in yeast.
- Biochemical methods for purifying and characterizing Atg23.
- Site-directed mutagenesis to disrupt Atg23 dimer formation.
Main Results:
- Atg23 exists as an elongated dimer (320 Å) and functions as a membrane-binding and -tethering protein.
- Mutations in a putative coiled-coil region prevent Atg23 dimerization, yielding a stable monomer.
- Expression of monomeric Atg23 in yeast disrupts Atg9 vesicle trafficking, reduces autophagy, and blocks the Cvt pathway.
Conclusions:
- Atg23 dimerization is critical for its membrane-tethering function.
- The dimeric state of Atg23 is essential for efficient Atg9 vesicle trafficking and autophagy initiation in yeast.
- Disruption of Atg23 dimerization impairs both nonselective autophagy and the selective Cvt pathway.
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