Dissecting carboxypeptidase E: properties, functions and pathophysiological roles in disease

Area of Science:

• Biochemistry
• Neuroendocrinology
• Molecular Biology

Background:

• Carboxypeptidase E (CPE) is a key enzyme in neuropeptide and peptide hormone biosynthesis.
• CPE exists in soluble and membrane-bound forms, each with distinct functions in hormone processing and secretion.
• CPE plays roles in protein internalization, vesicle transport, and signaling pathway regulation.

Purpose of the Study:

• To dissect the pathophysiological roles of Carboxypeptidase E (CPE) in endocrine and nervous systems.
• To investigate the consequences of CPE deficiency in mutant mouse models.
• To explore the involvement of CPE and its truncated form (ΔN-CPE) in tumorigenesis and disease diagnosis.

Main Methods:

• Utilized two types of CPE mutant mice (Cpe-deficient and Cpe knockout) to study loss-of-function phenotypes.
• Examined the biosynthesis pathways of neuropeptides and peptide hormones.
• Investigated the roles of soluble and membrane-bound CPE forms.

Main Results:

• Loss of normal CPE function in mutant mice leads to significant disorders, including diabetes, hyperproinsulinemia, low bone mineral density, and learning/memory deficits.
• Demonstrated the involvement of CPE in targeting prohormones to the regulated secretory pathway via its membrane form.
• Showcased the exopeptidase activity of soluble CPE in generating bioactive peptides from precursors.

Conclusions:

• CPE is essential for normal physiological function in both endocrine and nervous systems.
• CPE deficiency results in a spectrum of severe health disorders, underscoring its critical importance.
• Further research into CPE and its variants may offer insights into disease diagnosis and therapeutic strategies.