Capturing cargo and formation of prebudding complex

Stable Identifier
Reaction [binding]
Homo sapiens
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The cytoplasmic tails of MHC class I molecules do not possess any of the known ER export sequences. BAP31 acts as a cargo receptor by exporting peptide-loaded class I MHC molecules to the ER exit sites or ER/Golgi intermediate compartment. Sec24 of the Sec23-Sec24/Sar1-GTP complex catches cargo by direct contact, forming the prebudding complex. Sar1/Sec23-Sec24 can bring about curvature of the membrane in the formation of vesicle. The cargo (antigen-bound MHC) accumulates within the COPII vesicle by binding to the Sec24 polypeptide of the COPII coat.

SARS-CoV-2 ORF8 (8) induces BECN1-dependent autophagy to degrade class I MHC leading to impaired antigen presentation (Zhang Y et al. 2021).

Literature References
PubMed ID Title Journal Year
10825291 COPI-coated ER-to-Golgi transport complexes segregate from COPII in close proximity to ER exit sites

Paccaud, JP, Lin-Marq, N, Stephens, DJ, Pagano, A, Pepperkok, R

J Cell Sci 2000
11163199 Selective export of MHC class I molecules from the ER after their dissociation from TAP

Manley, H, Spiliotis, ET, Edidin, M, Zúñiga, MC, Osorio, M

Immunity 2000
10982397 Dynamics of transitional endoplasmic reticulum sites in vertebrate cells

Glick, BS, Hammond, AT

Mol Biol Cell 2000
This event is regulated
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