Amyloid precursor protein combinatorial phosphorylation code regulates AMPA receptor removal during distinct forms of...

Area of Science:

• Neuroscience
• Molecular Biology
• Cell Biology

Background:

• Synaptic plasticity is vital for memory and neural network stability.
• Impaired synaptic plasticity is a hallmark of neurodegenerative diseases like Alzheimer's disease (AD).
• The amyloid precursor protein (APP) is implicated in AD, but its physiological roles in synaptic plasticity remain unclear.

Purpose of the Study:

• To investigate the role of amyloid precursor protein (APP) in regulating AMPA receptor trafficking during synaptic plasticity.
• To identify specific phosphorylation sites on APP that control AMPA receptor internalization.
• To elucidate the mechanisms by which APP influences different forms of synaptic plasticity.

Main Methods:

• Investigated combinatorial phosphorylation sites within APP.
• Examined the regulation of AMPA receptor trafficking, specifically the GluA2 subunit.
• Studied homeostatic synaptic plasticity and NMDA receptor-dependent long-term depression.

Main Results:

• Identified dual phosphorylation sites (threonine-668/serine-675) on APP that promote GluA2 subunit endocytosis during homeostatic synaptic plasticity.
• Demonstrated APP's requirement for GluA2 internalization during NMDA receptor-dependent long-term depression via distinct phosphoresidues (serine-655/threonine-686).
• Established APP as a key regulator of AMPA receptor internalization during distinct plasticity forms, controlled by specific phosphorylation patterns.

Conclusions:

• Amyloid precursor protein (APP) acts as a central regulator of AMPA receptor internalization during various forms of synaptic plasticity.
• Specific combinations of APP phosphoresidues act as molecular switches, controlling receptor trafficking.
• These findings suggest a broad role for APP in learning and memory processes and highlight its potential as a therapeutic target in AD.