Highlights d ATP-binding cassette protein ABCF1 is a unique E2 ubiquitinconjugating enzyme d ABCF1 potentiates the shift from M1 to M2 macrophage polarization d ABCF1 promotes TLR4 endocytosis/TRIF pathway by K63 polyubiquitination of SYK d ABCF1 promotes SIRS to ET phase transition during sepsis thereby enhancing survival

Major histocompatibility complex class I (MHCI) proteins have been implicated in neuronal function through the modulation of neuritogenesis, synaptogenesis, synaptic plasticity, and memory consolidation during development. However, the involvement of MHCI in the aged brain is unclear. Here we demonstrate that MHCI deficiency results in significant dendritic atrophy along with an increase in thin dendritic spines and a reduction in stubby spines in the hippocampus of aged (12 month old) mice. Ultrastructural analyses revealed a decrease in spine head diameter and post synaptic density (PSD) area, as well as an increase in overall synapse density, and non-perforated, small spines. Interestingly, we found that the changes in synapse density and morphology appear relatively late (after the age of 6 months). Finally, we found a significant age dependent increase in the levels of the glutamate receptor, GluN2B in aged MHCI knockout mice, with no change in GluA2/3, VGluT1, PSD95 or synaptophysin. These results indicate that MHCI may be also be involved in maintaining brain integrity at post-developmental stages notably in the modulation of neuronal and spine morphology and synaptic function during non-pathological aging which could have significant implications for cognitive function.

Graphical abstractHighlights► All 4 major life cycle stages of Trypanosoma congolense were grown in the lab. ► Relative protein expression among the life cycle stages was studied by iTRAQ MS. ► Several known expression trends were observed and new patterns were identified. ► Special focus is given to lifecycle stage specific surface molecules. ► Six new proteins unique to T. congolense were discovered.