Related Experiment Video
Updated: Jun 26, 2026

Imaging ATG9A, a Multi-Spanning Membrane Protein
Published on: June 16, 2023
Double duty of Atg9 self-association in autophagosome biogenesis
Congcong He1, Misuzu Baba, Daniel J Klionsky
1Life Sciences Institute, and Departments of Molecular, Cellular and Developmental Biology and Biological Chemistry, University of Michigan, Ann Arbor, MI, USA.
Abstract:
The understanding of the membrane flow process during autophagosome formation is essential to illuminate the role of autophagy under various disease-causing conditions. Atg9 is the only identified integral membrane protein required for autophagosome formation, and it is thought to cycle between the membrane sources and the phagophore assembly site (PAS). Thus, Atg9 may play an important role as a membrane carrier. We report the self-interaction of Atg9 and generate an Atg9 mutant that is defective in this interaction. This mutation results in abnormal autophagy, due to altered phagophore formation as well as inefficient membrane delivery to the PAS. Based on our analyses, we discuss a model suggesting dual functions for the Atg9 complex: by reversibly binding to another Atg9 molecule, Atg9 can both promote lipid transport from the membrane origins to the PAS, and also help assemble an intact phagophore membrane.
Related Concept Videos
Autophagy
An autophagic pathway consists of a series of signaling events activated in response to diverse stress and physiological conditions such as food deprivation,...
Delivery Pathways to the Lysosome
Endocytosis
In endocytosis, the cell membrane takes up macromolecules and particles from the surrounding medium. Clathrin-mediated...
Coat Assembly and GTPases
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...
Export of Misfolded Proteins out of the ER
Autophagic Cell Death
Autophagy and Apoptosis
Autophagy can activate apoptosis. In normal conditions, the autophagy activating protein Beclin-1 and pro-apoptotic...
Intralumenal Vesicles and Multivesicular Bodies

