Synaptic multiprotein complexes associated with 5-HT(2C) receptors: a proteomic approach

Area of Science:

• Neuroscience
• Cell Biology
• Molecular Biology

Background:

• Membrane-bound receptors, like tyrosine kinases and ionotropic receptors, associate with extensive protein networks via protein-protein interactions.
• While these networks are key for cellular signaling, the protein complexes linked to G-protein-coupled receptors (GPCRs) remain less understood.

Purpose of the Study:

• To identify protein interactions with the C-terminal tail of the 5-hydroxytryptamine 2C (5-HT2C) receptor, a specific GPCR.
• To elucidate the protein network associated with the 5-HT2C receptor and its role in synaptic function.

Main Methods:

• Proteomic analysis using peptide affinity chromatography, mass spectrometry, and immunoblotting.
• Coimmunoprecipitation experiments to validate in vivo interactions.
• Electron microscopy to assess synaptic localization and colocalization.

Main Results:

• Identified 15 proteins interacting with the 5-HT2C receptor C-terminus.
• Key interacting proteins include synaptic multidomain proteins (PSD95, Veli3-CASK-Mint1 complex), cytoskeletal proteins, and signaling molecules.
• Confirmed in vivo interactions between 5-HT2C receptors and PSD95/Veli3-CASK-Mint1.
• Observed synaptic enrichment and colocalization of Veli3 and 5-HT2C receptors in choroidal cell microvilli.

Conclusions:

• The 5-HT2C receptor is part of complex protein networks.
• These networks are vital for the receptor's synaptic positioning and integration into signaling pathways.
• This study provides new insights into GPCR-associated protein complexes and their functional significance.