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Sec A 2 is not required for secretion of the surface autolysin Isp C in Listeria monocytogenes serotype 4b
Author(s) -
Ronholm Jennifer,
Zhang Cathy X.Y.,
Cao Xudong,
Lin Min
Publication year - 2014
Publication title -
journal of basic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0233-111X
DOI - 10.1002/jobm.201300007
Subject(s) - autolysin , secretion , biology , virulence , mutant , microbiology and biotechnology , listeria monocytogenes , biochemistry , bacteria , genetics , gene
Listeria monocytogenes is one of several Gram‐positive bacteria known to contain an auxiliary ATPase (SecA2) involved in the Sec secretion of a subset of proteins important to bacterial pathogenesis, including autolysins. It is not known if IspC, a novel surface‐associated autolysin essential for full virulence of L. monocytogenes serotype 4b, is SecA2‐dependent for secretion. By creating a s ecA2 gene deletion (Δ secA2 ) mutant from the wild type (WT) L. monocytogenes serotype 4b strain, in combination with the proteomic analysis of surface proteins and those secreted into the medium from both the mutant and the WT, we confirmed previous findings that two autolysins (p60 and NamA) are SecA2‐dependent for secretion. However, this approach did not identify IspC as one of the surface proteins affected by the SecA2 deletion. Further experiments with immunofluorescence microscopy and Western blotting indicated that IspC was well displayed on the surface of both the Δ secA2 mutant and WT cells, while p60 was not, clearly indicating that the secretion of IspC is not attributed to the SecA2 pathway. This finding sets IspC apart from other autolysins involved in virulence, such as p60 and NamA, in that SecA2 is not required for IspC secretion.