Post-translational processing targets functionally diverse proteins in Mycoplasma hyopneumoniae

Abstract

Mycoplasma hyopneumoniae is a genome-reduced, cell wall-less, bacterial pathogen with a predicted coding capacity of less than 700 proteins and is one of the smallest self-replicating pathogens. The cell surface of M. hyopneumoniae is extensively modified by processing events that target the P97 and P102 adhesin families. Here, we present analyses of the proteome of M. hyopneumoniae-type strain J using protein-centric approaches (one-and two-dimensional GeLC-MS/MS) that enabled us to focus on global processing events in this species. While these approaches only identified 52% of the predicted proteome (347 proteins), our analyses identified 35 surface-associated proteins with widely divergent functions that were targets of unusual endoproteolytic processing events, including cell adhesins, lipoproteins and proteins with canonical functions in the cytosol that moonlight on the cell surface. Affinity chromatography assays that separately used heparin, fibronectin, actin and host epithelial cell surface proteins as bait recovered cleavage products derived from these processed proteins, suggesting these fragments interact directly with the bait proteins and display previously unrecognized adhesive functions. We hypothesize that protein processing is underestimated as a post-translational modification in genome-reduced bacteria and prokaryotes more broadly, and represents an important mechanism for creating cell surface protein diversity.

Hydrogen peroxide production and myo‐inositol metabolism as important traits for virulence ofMycoplasma hyopneumoniae

“…This could be an indication that either this enzyme undergoes post‐translational modifications in order to be active and/or the availability of the substrate (glycerol) intracellularly might be a limiting step for its activity. Post‐translational modifications have been extensively reported experimentally in several proteins of M. hyopneumoniae (Djordjevic et al ., ; Burnett et al ., ; Pinto et al ., ; Seymour et al ., ; Tacchi et al ., ). From transcriptomic and proteomic literature data, we were not able to find any enlightening differences in this pathway between strains or species (Supporting Information Table S7).…”

Update onMycoplasma hyopneumoniaeinfections in pigs: Knowledge gaps for improved disease control

“…Like that, Tacchi et al. () identified 35 proteins that are endoproteolytically cleaved in M. hyopneumoniae . These include not only adhesins but also lipoproteins and even multifunctional cytosolic proteins “moonlighting” at the cell surface.…”

“…Interaction with surface accessible actin on the epithelial cells and causing cytoskeletal rearrangements allows the organism being phagocytosed. It is hypothesized that M. hyopneumoniae can survive within the phagolysosome, escape it and reside within the cytoplasm (Tacchi et al., ). Therefore, it can not only evade the immune system but could disseminate to internal organs and persist within its host without causing disease.…”

Comparative proteomics of twoMycoplasma hyopneumoniaestrains andMycoplasma flocculareidentified potential porcine enzootic pneumonia determinants

“…This suggests that these proteins are more fragmented in the cell surface than in in the cytoplasm, when they are expected to be mostly unprocessed. Previous studies have showed that adhesins are targets of post-translational proteolytic events [20–24] which can be differential between M. hyopneumoniae strains [15]. Along with differential adhesin abundance, the possibly differential adhesin post-translational proteolytic processing likely impact on bacterial pathogenicity and deserve further investigation.…”