SpyAD, a Moonlighting Protein of Group A Streptococcus Contributing to Bacterial Division and Host Cell Adhesion

Abstract

c Group A streptococcus (GAS) is a human pathogen causing a wide repertoire of mild and severe diseases for which no vaccine is yet available. We recently reported the identification of three protein antigens that in combination conferred wide protection against GAS infection in mice. Here we focused our attention on the characterization of one of these three antigens, Spy0269, a highly conserved, surface-exposed, and immunogenic protein of unknown function. Deletion of the spy0269 gene in a GAS M1 isolate resulted in very long bacterial chains, which is indicative of an impaired capacity of the knockout mutant to properly divide. Confocal microscopy and immunoprecipitation experiments demonstrated that the protein was mainly localized at the cell septum and could interact in vitro with the cell division protein FtsZ, leading us to hypothesize that Spy0269 is a member of the GAS divisome machinery. Predicted structural domains and sequence homologies with known streptococcal adhesins suggested that this antigen could also play a role in mediating GAS interaction with host cells. This hypothesis was confirmed by showing that recombinant Spy0269 could bind to mammalian epithelial cells in vitro and that Lactococcus lactis expressing Spy0269 on its cell surface could adhere to mammalian cells in vitro and to mice nasal mucosa in vivo. On the basis of these data, we believe that Spy0269 is involved both in bacterial cell division and in adhesion to host cells and we propose to rename this multifunctional moonlighting protein as SpyAD (Streptococcus pyogenes Adhesion and Division protein).

The pan-genome of Lactobacillus reuteri strains originating from the pig gastrointestinal tract

“…Of the 22 genes encoding proteins >60 amino acids that were specific to pig cluster V (Table 4 ), several represented mobile genetic elements, including transposons and phage-related sequences. However, four lineage-specific surface proteins were detected, three of which contained a SEC10/PgrA surface exclusion domain, found in Gram-positive adhesins such as SpyAD from Group A Streptococci and implicated in cell adhesion [ 50 ]. Two of these SEC10/PgrA proteins (homologues of LR202_01429 and _02163) also contained a Rib/alpha-like repeat from the Rib adhesin of Group B Streptococci [ 51 ].…”

Identification of the Streptococcus pyogenes surface antigens recognised by pooled human immunoglobulin

“…Of the 94 proteins identified, only ten were recovered from all 20 isolates, suggesting that these antigens are reproducibly expressed by all four invasive serotypes selected for study, and share a high degree of sequence identity between serotypes. These conserved antigens included virulence factors (C5a peptidase 13 , and SpyAD 14 ), lipoproteins (maltose/maltodextrin-binding protein, oligopeptide-binding protein and nucleoside-binding protein), other cell wall-attached, LPXTG motif-containing molecules (putative pullulanase) and a single, abundant cytoplasmic protein (Chaperone protein DnaK) previously shown to stimulate in vivo antibody production 15 . Two of the proteins had no attributed function despite their clear degree of conservation and propensity to generate a strong humoral immune response during S. pyogenes infection (hypothetical membrane associated protein and cell surface protein).…”

Streptococcus pyogenes genes that promote pharyngitis in primates

“…Importantly, we recently reported that SpyAD is also crucial for GAS virulence during necrotizing myositis and female genital tract infections in NHPs (32,33). The critical roles in multiple infection models suggest SpyAD could be an attractive vaccine target (62,82). Further investigations are needed to test whether immunizing NHPs with proteins we identified in this study could evoke protective immunity against GAS pharyngitis.…”

“…In aggregate, 698 fitness genes were identified. These identified fitness genes encode many known GAS virulence factors, such as C5a peptidase (ScpA) (51, 52), streptococcal inhibitor of complement (Sic) (53,54), antiphagocytic M protein (55), secreted DNAses (Spd, Spd3, and SdaD2) (45,56,57), surface-exposed adhesins and invasins (SclA, Enn, serum opacity factor [Sof], Streptococcus pyogenes adhesion and division [SpyAD], and EftLSLB) (33,(58)(59)(60)(61)(62)(63), and secreted toxins (SpeJ, SpeG, and SpyA) (49, 64) ( Figure 1). A common set of 115 genes was found to be important for GAS fitness for both M1 and M28 organisms ( Figure 1 and Supplemental Table 3).…”