A non-canonical ARMS-GABARAP interaction modulates dendritic spine formation and synaptic development

Area of Science:

• Neuroscience
• Molecular Biology
• Cell Biology

Background:

• Ankyrin repeat-rich membrane spanning (ARMS) is crucial for neuronal function, but its regulation is unclear.
• Understanding ARMS regulation is key to addressing neurodevelopmental and neurodegenerative disorders.

Purpose of the Study:

• To identify novel ARMS-binding proteins and elucidate their regulatory mechanisms.
• To investigate the role of the ARMS-GABARAP complex in neuronal function and protein homeostasis.

Main Methods:

• Co-immunoprecipitation and crystal structure analysis to determine the ARMS-GABARAP interaction.
• Functional assays in hippocampal neurons to assess the complex's role in dendritic spine development.
• Peptide-based disruption of the ARMS-GABARAP complex to study ARMS localization.

Main Results:

• GABARAP, an Atg8-family protein, directly binds to ARMS via its N-terminal ankyrin repeats.
• The ARMS-GABARAP interaction is structurally unique and specific to the GABARAP subfamily.
• GABARAP negatively regulates ARMS-mediated dendritic spine maturation.
• Disruption of the complex alters ARMS subcellular localization, leading to soma accumulation.

Conclusions:

• A novel interaction mechanism between ARMS and GABARAP is identified.
• The ARMS-GABARAP complex plays a regulatory role in neuronal protein homeostasis.
• This interaction presents a potential therapeutic target for neurological disorders.