Distribution of Protein A on the Surface ofStaphylococcus aureus

Abstract

Surface proteins of Staphylococcus aureus fulfill many important roles during the pathogenesis of human infections and are anchored to the cell wall envelope by sortases. Although the chemical linkage of proteins to cell wall cross bridges is known, the mechanisms whereby polypeptides are distributed on the staphylococcal surface have not been revealed. We show here that protein A, the ligand of immunoglobulin, is unevenly distributed over the staphylococcal surface. Upon removal with trypsin, newly synthesized polypeptide is deposited at two to four discrete foci. During subsequent growth, protein A appears to be slowly distributed from these sites. When viewed through multiple focal planes by laser scanning microscopy, protein A foci are arranged in a circle surrounding the bacterial cell. This pattern of distribution requires the LPXTG sorting signal of protein A as well as sortase A, the transpeptidase that anchors polypeptides to cell wall cross bridges. A model is presented whereby protein A deposition at discrete sites coupled with cell wall synthesis enables distribution of protein A on the staphylococcal surface.

Peptidoglycan architecture can specify division planes in Staphylococcus aureus

“…Dynamic environmental conditions, such as those encountered during pathogenesis, will lead to alterations in surface protein expression. Th us, cells may also inherit a surface protein complement with heterogeneity within the population, especially of those proteins only attached during septum formation 32,33 . Such population-wide heterogeneity may provide a selective advantage in the ever-changing complex interaction between pathogen and host.…”

EsaD, a Secretion Factor for the Ess Pathway inStaphylococcus aureus

“…Microscopic observation of intact cells was performed as previously described (12). Briefly, overnight cultures of S. aureus cells were diluted 1:100 into fresh growth medium and grown to mid-log phase (A 600 of 1).…”

The Giant Protein Ebh Is a Determinant of Staphylococcus aureus Cell Size and Complement Resistance

“…2A). Staphylococci displayed a spherical distribution of anti-Ebh N staining, similar to that of sortase-anchored surface proteins secreted via YSIRK-G/S-type signal peptides (11). Anti-Ebh N staining also generated immunofluorescence signals on the surface of S. aureus Newman, albeit that the fluorescence signals were less intense and less homogeneous than those for USA300 LAC (Fig.…”

“…Upon completion of peptidoglycan synthesis, staphylococci split cross walls down the middle, thereby separating daughter cells that form new cross walls in a plane perpendicular to their previous division plane (9). Cell wall synthesis and cell separation at the cross wall require protein traffic into this compartment (10)(11)(12)(13). Several precursor proteins with signal peptides that bear a YSIRK-G/S motif have been shown to be secreted at the cross wall, including sortase-anchored surface proteins (12), Geh (lipase) (14), and LytN, a murein hydrolase responsible for cross wall splitting (10).…”