Adaptor protein complex interaction map in Arabidopsis identifies P34 as a common stability regulator

Area of Science:

• Plant cell biology
• Molecular and cellular trafficking
• Proteomics

Background:

• Adaptor protein (AP) complexes are crucial for vesicle transport, mediating the recruitment of coat proteins, membrane cargoes, and accessory proteins.
• In plants, endocytic and post-Golgi trafficking pathways converge at the trans-Golgi network, necessitating specialized cargo sorting mechanisms.
• The specific cargoes, accessory proteins, and regulatory mechanisms of plant AP complexes remain largely uncharacterized.

Purpose of the Study:

• To comprehensively map the interactome of plant AP complexes and the TPLATE complex in Arabidopsis thaliana.
• To identify novel proteins associated with AP complexes and elucidate their roles in plant endomembrane trafficking.

Main Methods:

• Utilized various proteomics approaches to generate the overall interactome of five AP complexes and the TPLATE complex.
• Investigated protein-protein interactions and functional roles through biochemical and cellular assays.

Main Results:

• The study identified a novel hub protein, P34 (adaptin binding-like protein), within the AP interactome network.
• P34 directly interacts with clathrin-associated AP complexes, stabilizing them and influencing clathrin-mediated endocytosis.
• The findings reveal P34's significant role in regulating various post-Golgi trafficking routes in plant cells.

Conclusions:

• The generated AP interactome network provides a valuable resource for discovering new regulators of plant endomembrane trafficking.
• P34 emerges as a critical component influencing the stability and function of AP complexes in clathrin-mediated endocytosis and trafficking.