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Updated: May 15, 2026

Measuring Peptide Translocation into Large Unilamellar Vesicles
Published on: January 27, 2012
Assaying peptide translocation by the peptide transporter TAP
Marlieke L M Jongsma1, Jacques Neefjes2
1Department of Cell Biology II, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
The Transporter Associated with Antigen Processing (TAP) moves peptides into the endoplasmic reticulum for MHC class I presentation. This study outlines methods to assay TAP activity and identify its inhibitors.
Area of Science:
- Immunology
- Molecular Biology
- Cell Biology
Background:
- MHC class I molecules present peptides derived from cytosolic/nuclear proteins.
- Peptide loading of MHC class I occurs in the ER lumen.
- Cytosolic peptides require translocation across the ER membrane for loading.
Purpose of the Study:
- To describe methods for assaying peptide translocation by TAP.
- To outline strategies for identifying TAP inhibitors.
- To understand the critical role of TAP in MHC class I antigen presentation.
Main Methods:
- Assay development for peptide translocation by TAP.
- Screening for inhibitors of TAP activity.
- Analysis of TAP function in antigen presentation.
Main Results:
- Established methods to quantify TAP-mediated peptide transport.
- Identified potential chemical and viral inhibitors of TAP.
- Demonstrated the impact of TAP inhibition on MHC class I presentation.
Conclusions:
- TAP is essential for efficient MHC class I antigen presentation.
- Assays for TAP activity are crucial for drug discovery and virology.
- Understanding TAP function provides insights into immune evasion strategies.
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