Posttranslational modifications: an emerging functional layer of diet-host-microbe interactions

The microbiome plays a vital role in human health, with changes in its composition impacting various aspects of the body. Posttranslational modification(PTM) regulates protein activity by attaching chemical groups to amino acids in an enzymatic or non-enzymatic manner. PTMs offerfast and dynamic regulation of protein expression and can be influencedby specificdietary components that induce PTM events in gut microbiomes and their hosts. PTMs on microbiome proteins have been found to contribute to host-microbe interactions. For example, in Escherichia coli, S-sulfhydration of tryptophanase regulates uremic toxin production and chronic kidney disease in mice. On a broader microbial scale, the microbiomes of patients with inflammatorybowel disease exhibit distinct PTM patterns in their metaproteomes. Moreover, pathogens and commensals can alter host PTM profilesthrough protein secretion and diet-regulated metabolic shifts. The emerging fieldof metaPTMomics focuses on understanding PTM profilesin the microbiota, their association with lifestyle factors like diet, and their functional effectson host-microbe interactions.