C-terminal motif of human neuropeptide Y₄ receptor determines internalization and arrestin recruitment

Area of Science:

• Pharmacology
• Cell Biology
• Molecular Biology

Background:

• The human neuropeptide Y4 receptor (hY4R) is a G protein-coupled receptor (GPCR) involved in appetite regulation.
• GPCR internalization and trafficking are critical for modulating receptor signaling, making them important for understanding disease mechanisms.

Purpose of the Study:

• To elucidate the molecular mechanism of hY4R desensitization and endocytosis.
• To identify the specific regions and amino acids within the hY4R carboxyl terminus responsible for its internalization.

Main Methods:

• Site-directed mutagenesis to create C-terminal deletion mutants and single amino acid substitutions.
• Fluorescence microscopy, binding assays, and inositol turnover experiments.
• Bioluminescence resonance energy transfer (BRET) assays to study hY4R interaction with arrestin-3.

Main Results:

• A specific motif (EESEHLPLSTVHTEVSKGS) in the hY4R carboxyl terminus was identified as essential for internalization.
• Glutamate, threonine, and serine residues within this motif were found to play critical roles.
• The identified motif regulates arrestin-3 recruitment and subsequent receptor endocytosis.

Conclusions:

• The study successfully identified the internalization motif of the human neuropeptide Y4 receptor.
• This finding provides a molecular understanding of hY4R trafficking and desensitization.
• The identified motif and its key residues are crucial for arrestin-3 mediated endocytosis, offering potential therapeutic targets for metabolic diseases.