Uncovering the glutamate carboxypeptidase II microenvironment using a multi-labeling proteomic approach

Area of Science:

• Biochemistry
• Molecular Biology
• Proteomics

Background:

• Glutamate carboxypeptidase II (GCPII) is a membrane-bound enzyme with elevated levels in prostate cancer.
• Its precise physiological role in prostate tissue is not well understood.
• GCPII is a significant target for prostate cancer imaging and therapy.

Purpose of the Study:

• To elucidate the physiological function of GCPII in prostate tissue.
• To identify proteins interacting with GCPII using proximity labeling.
• To develop and optimize a proximity proteomics strategy for membrane protein interactome mapping.

Main Methods:

• Utilized proximity labeling technologies (HRP, µMap, RTA) integrated with the iBody platform targeting GCPII.
• Performed proteomic profiling on U251 MG-GCPII cells using mass spectrometry and label-free quantification.
• Validated identified proteins via Western blot and GCPII pulldown assays.

Main Results:

• Identified a network of proteins associated with GCPII.
• These proteins are potentially involved in cancer metabolism, migration, invasiveness, progression, and immune evasion.
• Riboflavin tetraacetate-based iBody labeling demonstrated high precision for interactome mapping.

Conclusions:

• The study identifies novel GCPII-associated proteins, offering insights into its function in prostate cancer.
• The developed proximity proteomics strategy provides a robust framework for membrane protein interactome studies.
• Riboflavin tetraacetate-based labeling shows significant promise for precise membrane protein interactome mapping.