TAPBP
Overview
TAPBP (TAP Binding Protein), also known as Tapasin, encodes a chaperone protein that bridges the TAP transporter to MHC class I molecules during peptide loading in the endoplasmic reticulum. TAPBP is an essential component of the peptide-loading complex (PLC), and its loss impairs efficient MHC class I surface expression and antigen presentation.
Alterations observed in the corpus
- Component of the MHC class I antigen-processing machinery (APM); enriched for somatic mutations in TIL-rich colorectal tumors, consistent with immune-escape selection pressure in tumors with high neoantigen load, in a cohort of 619 CRC cases PMID:27149842.
Cancer types (linked)
- COAD / Colorectal cancer: Somatic mutations in APM components including TAPBP are enriched in TIL-rich tumors, suggesting adaptive immune-escape selection PMID:27149842.
Co-occurrence and mutual exclusivity
Therapeutic relevance
- APM gene mutations including TAPBP are candidate adaptive resistance mechanisms to immune-checkpoint blockade; functional loss of tapasin reduces peptide-MHC-I stability and could reduce T-cell recognition of tumor antigens PMID:27149842.
Open questions
- Whether TAPBP mutations confer primary or acquired resistance to checkpoint inhibitors in colorectal cancer was not tested in the citing study PMID:27149842.
Sources
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