Roles of proteolysis in regulation of GPCR function.

Area of Science:

• Biochemistry
• Cell Biology
• Pharmacology

Background:

• Enzymatic activity of peptidases requires strict regulation to prevent uncontrolled peptide bond hydrolysis.
• Peptidases are regulated through various mechanisms, including inactive propeptidase forms, endogenous inhibitors, compartmentalization, and pH-dependent activity.

Purpose of the Study:

• To review the diverse roles of proteolysis in regulating G protein-coupled receptors (GPCRs).
• To highlight how peptidases, both at the cell surface and intracellularly, modulate GPCR signaling pathways.

Main Methods:

• Literature review of studies on peptidase regulation of GPCRs.
• Analysis of mechanisms including peptide inactivation/generation, transactivation, direct signaling, and intracellular degradation.

Main Results:

• Cell-surface peptidases can inactivate signaling peptides, generate activating peptides, or mediate transactivation of receptor tyrosine kinases.
• Intracellular peptidases regulate GPCRs by degradation in lysosomes, processing internalized agonists in endosomes, and modulating ubiquitination.
• Certain peptidases can directly signal by cleaving GPCRs to initiate intracellular cascades.

Conclusions:

• Proteolysis plays a multifaceted role in GPCR regulation, impacting signaling, desensitization, and degradation.
• Targeting peptidase-GPCR interactions presents promising therapeutic avenues for diseases involving dysregulated GPCR signaling.