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Identification of incompletely processed potential carboxypeptidase E substrates from CpEfat/CpEfat mice
E J Bures1, P L Courchesne, J Douglass
1Departments of Biochemistry and Genetics, Amgen, Thousand Oaks, CA, USA.
Proteomics
|October 30, 2001
Summary
Researchers identified peptides linked to obesity in Carboxypeptidase E-deficient mice. This study used an affinity-based method to uncover differences in neuropeptide processing, revealing potential therapeutic targets for metabolic disorders.
Area of Science:
- Neuroendocrinology
- Molecular Biology
- Metabolomics
Background:
- Obesity is a complex metabolic disorder associated with dysregulation of neuropeptide processing.
- Carboxypeptidase E (CpE) plays a crucial role in the post-translational modification of prohormones and neuropeptides.
- CpE-deficient (CpEfat/CpEfat) mice exhibit an obese phenotype, suggesting CpE's involvement in weight regulation.
Purpose of the Study:
- To identify specific peptides affected by CpE deficiency in neuroendocrine tissues.
- To investigate the role of CpE in neuropeptide processing and its contribution to the obese phenotype.
- To develop and validate an affinity-based enrichment strategy for identifying CpE substrates.
Main Methods:
- Neuroendocrine tissue samples were collected from wild-type and CpEfat/CpEfat mice.
- Peptides with basic C-termini, potential CpE substrates, were enriched using an anhydrotrypsin affinity column.
- Enriched peptides were analyzed by liquid chromatography-mass spectrometry (LC-MS) and targeted LC-tandem mass spectrometry (LC-MS/MS).
Main Results:
- An affinity-based enrichment strategy successfully isolated peptides with basic C-termini.
- LC-MS/MS analysis identified 27 peptides derived from known neuropeptides and 25 peptides from novel protein sources.
- Elevated levels of specific neuropeptide-derived peptides were observed in CpEfat/CpEfat mice, including substrates of CpE such as proSAAS.
Conclusions:
- The study successfully identified peptides differentially regulated in CpE-deficient mice, implicating altered neuropeptide processing in obesity.
- The affinity-based enrichment method is a feasible approach for discovering CpE substrates and studying neuropeptide processing pathways.
- These findings provide insights into the molecular mechanisms underlying CpE-related obesity and suggest potential targets for therapeutic intervention.
