Versatile Signaling Activity of Adhesion GPCRs

Area of Science:

• Molecular and Cellular Biology
• Biochemistry
• Pharmacology

Background:

• Adhesion G protein-coupled receptors (aGPCRs) comprise 33 human receptors involved in numerous biological processes.
• These receptors feature large N-termini (NT) with adhesion domains and a conserved GPCR autoproteolysis-inducing (GAIN) domain.
• The GAIN domain mediates autoproteolysis, separating the receptor into non-covalently linked N-terminal and C-terminal fragments.

Purpose of the Study:

• To investigate the role of the N-terminal region in aGPCR activation.
• To elucidate the mechanisms underlying constitutive activation upon N-terminal deletion.
• To understand the contribution of the N-terminal stalk region to receptor signaling.

Main Methods:

• Analysis of receptor structure and function related to N-terminal domains.
• Investigating the impact of N-terminal deletions on receptor activity.
• Characterizing the N-terminal stalk region and its potential agonistic peptide sequences.

Main Results:

• Deletion or removal of the N-terminus up to the GAIN cleavage site results in constitutive receptor activation.
• For some aGPCRs, activation depends on unmasking agonistic peptide sequences in the N-terminal stalk.
• The importance of specific stalk sequences for activation varies significantly among different aGPCRs.

Conclusions:

• The N-terminal region plays a critical role in regulating aGPCR activity.
• Constitutive activation via N-terminal deletion reveals insights into receptor gating mechanisms.
• aGPCRs exhibit versatile signaling capabilities, fine-tuned for specific physiological roles.