Conformational regulation of AP1 and AP2 clathrin adaptor complexes

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• Heterotetrameric clathrin adaptor protein complexes (APs) are crucial for intracellular vesicle trafficking.
• AP1 and AP2 complexes bind specific membrane lipids (PI4P and PI(4,5)P2, respectively) and cargo at distinct cellular locations.

Purpose of the Study:

• To review recent advances in understanding the molecular mechanisms regulating AP1 and AP2 activation and conformational changes.
• To explore how various inputs, including lipids, cargo, and accessory proteins, influence AP function.

Main Methods:

• This review synthesizes findings from structural, biochemical, and genetic studies.
• It integrates data on protein-protein interactions and regulatory pathways.

Main Results:

• APs cycle through active and inactive states via conformational rearrangements and reversible phosphorylation.
• Membrane lipids, transmembrane cargo, clathrin, and accessory proteins like Arf1 and FCHo stimulate AP activation.
• Phosphorylation and NECAP facilitate the return of APs to an inactive state.

Conclusions:

• Multiple molecular inputs converge to regulate AP1 and AP2 conformation and activity.
• Understanding these regulatory mechanisms is vital, as viruses exploit AP pathways for their replication.