The recently discovered peptide editor TAPBPR binds to UDP-glucose:glycoprotein glucosyltransferase 1 to provide quality control in the antigen presentation pathway by facilitating the reglucosylation of the glycan on MHC class I molecules.
The number of different peptides presented by major histocompatibility complex class I molecules to the immune system's T lymphocytes is inversely correlated with cell surface expression and is strongly associated with the response to infectious disease.
Immunopeptidomics in combination with novel cell-based assays that assess peptide exchange reveal a critical role for the K22-D35 loop of TAPBPR in mediating peptide dissociation and peptide selection on MHC I.
A generally applicable two-hybrid assay demonstrates that MHC class I heavy chains devoid of beta-2 microglobulin associate within and across allotypes, with implications for endocytosis and autoimmunity.
A near-complete flux balance analysis model of a minimal cell demonstrates the high essentiality of its metabolic genes, agrees well with experimental essentiality data and suggests some further gene removals.