Analysis of expression of a cytosolic enzyme on the surface of Streptococcus pyogenes

The normally cytosolic glycolytic enzyme, glyceraldehyde-3-phosphate dehydr ogenase, (GAPDH) has been reported to be expressed on the surface of Strept ococcus pyogenes, group A, where it can act as a plasmin binding protein (P lr), and potentially a signaling molecule. In studies of wild-type and isog enic mutants, an association between surface expression of antigenic GAPDH/ Plr and M and M-related fibrinogen-binding proteins was identified. Inactiv ation of the mga gene, whose product controls expression of M and M-related proteins also influenced expression of surface GAPDH/Plr. Revertants or ps eudorevertants of mga mutants led to concomitant re-expression of surface G APDH/Plr and M and M-related proteins. Using surface enhanced laser desorpt ion ionization (SELDI) mass spectroscopy, a physical association between GA PDH/Plr and streptococcal fibrinogen-binding proteins was demonstrated. The se studies support the hypothesis that surface M and M-related proteins are involved in anchoring GAPDH/Plr on the surface of group A streptococci. (C ) 2000 Academic Press.