Pneumococcal Extracellular Serine Proteases: Molecular Analysis and Impact on Colonization and Disease

Abstract

The pathobiont Streptococcus pneumoniae causes life-threatening diseases, including pneumonia, sepsis, meningitis, or non-invasive infections such as otitis media. Serine proteases are enzymes that have been emerged during evolution as one of the most abundant and functionally diverse group of proteins in eukaryotic and prokaryotic organisms. S. pneumoniae expresses up to four extracellular serine proteases belonging to the category of trypsin-like or subtilisin-like family proteins: HtrA, SFP, PrtA, and CbpG. These serine proteases have recently received increasing attention because of their immunogenicity and pivotal role in the interaction with host proteins. This review is summarizing and focusing on the molecular and functional analysis of pneumococcal serine proteases, thereby discussing their contribution to pathogenesis.

Facultative symbiont virulence determines horizontal transmission rate without host specificity in Dictyostelium discoideum social amoebas

“…We identified several candidate genes that may confer increased malevolence to bb395 and bb433 in their shared structural variant. Among these, PB395_00119/PB433_00119 encode a putative member of the peptidase S8 family (also called subtilisin-related peptidases) that are known contributors to the pathogenesis of Streptococcus pneumoniae ( Ali et al, 2021 ). Interestingly, there are no closely related homologs in other sequenced Paraburkholderia genomes, but proteins with the highest similarity in GenBank are found in Burkholderia pseudomallei (MBF3536330.1, 93% identity over the length of the protein) and Ralstonia solanacearum (NKA33280.1, 93% identity over the length of the protein), which are, respectively, pathogens of mammals and plants.…”

Establishment of Streptococcus suis Biofilm Infection Model In Vivo and Comparative Analysis of Gene Expression Profiles between In Vivo and In Vitro Biofilms

“…When it comes to the genes screened in this study both in vitro and in vivo , 21 of the 33 genes screened are related to bacterial metabolism, but few of these screened genes have been shown to be involved in biofilm formation in previous studies. Among them, ZY05719_09405 encodes a subtilis-like serine protease related to proteolysis, and its homologues in species like Vibrio cholerae and Streptococcus pneumoniae are closely related to the dispersal of bacterial biofilms ( 33 , 34 ). ZY05719_09670 encodes a transcriptional regulator belonging to the MarR family, which has been shown to be involved in negatively regulating bacterial biofilm formation in a variety of bacteria, including SarZ in Staphylococcus aureus ( 35 ), BifR in Burkholderia thailandensis ( 36 ), and EspR in Streptococcus mutans ( 37 ).…”

Pneumococcus downregulates the molecular weight of the extracellular domain of the epidermal growth factor receptor of alveolar epithelial cells

“…We previously reported that neutrophil elastase, an aggravation factor of pneumococcal pneumonia, degrades the extracellular domain (ECD) of the epidermal growth factor receptor (EGFR) on the alveolar epithelial cell, thereby disrupting the stability of the alveolar epithelial barrier 2 . Additionally, pneumococcal proteases are released into lung tissues during pneumococcal pneumonia 3 . We hypothesized that EGFR ECD is degraded by pneumococcal proteases that disrupt the alveolar epithelial barrier's stability.…”

“…2 Additionally, pneumococcal proteases are released into lung tissues during pneumococcal pneumonia. 3 We hypothesized that EGFR ECD is degraded by pneumococcal proteases that disrupt the alveolar epithelial barrier's stability. In this study, we investigated the degradation of EGFR by pneumococcal proteases.…”