Carboxypeptidase Y: structural basis for protein sorting and catalytic triad

Area of Science:

• Biochemistry
• Molecular Biology
• Cell Biology

Background:

• Carboxypeptidase Y (CPY) is a yeast vacuolar protease involved in C-terminal peptide processing.
• Its precise function and transport mechanisms are key areas of study in eukaryotic protein sorting.
• The CPY pathway serves as a model for understanding protein trafficking.

Purpose of the Study:

• To elucidate the functional roles of Carboxypeptidase Y (CPY).
• To explore the structural basis for CPY's unique enzymatic properties.
• To discuss CPY's significance in protein sorting and post-translational modifications.

Main Methods:

• Analysis of the CPY biosynthetic pathway in yeast.
• Identification of post-translational modifications during CPY transport.
• Structural analysis of CPY active site and unique features.

Main Results:

• CPY is synthesized as a prepro-form and undergoes processing through the ER and Golgi to vacuoles.
• Post-translational modifications include glycosylation and pre-segment cleavage.
• CPY exhibits unique structural features, including a catalytic triad, conserved cysteine, and disulfide zipper, contributing to its wide pH optimum, especially at acidic pH.

Conclusions:

• CPY's structural properties underpin its function as a serine protease with a broad pH activity range.
• The study provides insights into the structural basis of CPY's unique characteristics.
• Understanding CPY structure aids in comprehending eukaryotic protein sorting and function.