SpyAD, a moonlighting protein of group A Streptococcus contributing to bacterial division and host cell adhesion.
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).
Novartis Vaccines and Diagnostics Srl, Siena, Italy.
Marilena
M
Gallotta
Novartis Vaccines and Diagnostics Srl, Siena, Italy.
Giovanni
G
Gancitano
Department of Molecular Medicine, Institute of Biochemistry, University of Pavia, Pavia, Italy.
Giampiero
G
Pietrocola
Novartis Vaccines and Diagnostics Srl, Siena, Italy.
Marirosa
M
Mora
Novartis Vaccines and Diagnostics Srl, Siena, Italy.
Alfredo
A
Pezzicoli
Novartis Vaccines and Diagnostics Srl, Siena, Italy.
Giovanna
G
Tuscano
Novartis Vaccines and Diagnostics Srl, Siena, Italy.
Emiliano
E
Chiarot
Novartis Vaccines and Diagnostics Srl, Siena, Italy.
Vincenzo
V
Nardi-Dei
Centre for High Instruments, Electron Microscopy Section, University of Tuscia, Viterbo, Italy.
Anna Rita
AR
Taddei
Department of Molecular Medicine, Institute of Biochemistry, University of Pavia, Pavia, Italy.
Simonetta
S
Rindi
Department of Molecular Medicine, Institute of Biochemistry, University of Pavia, Pavia, Italy.
Pietro
P
Speziale
Novartis Vaccines and Diagnostics Srl, Siena, Italy.
Marco
M
Soriani
Novartis Vaccines and Diagnostics Srl, Siena, Italy immaculada.margarit_y_ros@novartis.com guido.grandi@novartis.com.
Guido
G
Grandi
Novartis Vaccines and Diagnostics Srl, Siena, Italy immaculada.margarit_y_ros@novartis.com guido.grandi@novartis.com.
Immaculada
I
Margarit
Novartis Vaccines and Diagnostics Srl, Siena, Italy.
Giuliano
G
Bensi
D000942:Antigens, Bacterial; D001422:Bacterial Adhesion / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D003001:Cloning, Molecular; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism; D004847:Epithelial Cells / Q000382:microbiology; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial / Q000276:immunology*; D006801:Humans; D013294:Lactococcus lactis / Q000378:metabolism; D011485:Protein Binding; D013297:Streptococcus pyogenes / Q000166:cytology / Q000235:genetics / Q000378:metabolism*
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins; C071525:FtsZ protein, Bacteria