CCK(-like) and receptors: structure and phylogeny in a comparative perspective

Area of Science:

• Comparative physiology
• Evolutionary biology
• Molecular endocrinology

Background:

• Cholecystokinin (CCK) and gastrin are key regulatory peptides in vertebrates, with homologs like cionin, neuropeptide-like protein 12, and sulfakinin (SK) in invertebrates.
• These peptides interact with G-protein-coupled receptors, influencing diverse physiological processes.

Purpose of the Study:

• To conduct a comparative review of CCK-like peptides and their receptors across metazoans.
• To analyze their molecular structure, physiological functions, and evolutionary history.

Main Methods:

• Comparative analysis of molecular structures.
• Review of physiological functions.
• Phylogenetic analysis of CCK-like peptides and receptors.

Main Results:

• CCK signaling regulates satiety, gastric acid, pancreatic secretion, anxiety, and memory in vertebrates.
• Sulfakinin (SK) in arthropods shares functions in satiety and gastrointestinal motility.
• Co-evolution of peptide and receptor is evident, with CCK-like receptors originating from a common ancestor.
• Receptor evolution shows species-specific events in arthropods and potential roles of tetraploidization.
• Sulfakinin receptor numbers vary (0-2) in arthropods, unlike the consistent 2 in chordates and nematodes.

Conclusions:

• The CCK signaling system is ancient and conserved across metazoans, with functional parallels between vertebrates and arthropods.
• Receptor evolution is complex, involving common ancestry and arthropod-specific diversification.
• The presence or absence of the SK signaling system may correlate with feeding behaviors in arthropods.