Fig. 8

Schematic presentation of the suggested role of Syk in microglia as a factor in cell adhesion modulation by pneumococci. In resting microglia, the active phosphorylated Syk (pSyk) is associated with focal adhesions (as described in the literature). A sufficient number of focal adhesions is required in order to achieve cell motility. Upon exposure to pneumococcal lysates, the activity of Syk increases. Syk is recruited to phagosomes, but is depleted from focal adhesions; the number of focal adhesions drops, and motility is reduced. Upon exposure to mannan, the mannose receptor association with bacterial products is reduced, and the active Syk molecules remain associated with focal adhesions and are not recruited to phagosomes; microglial motility remains high. Upon application of R406, Syk is inhibited, including at the sites with focal adhesions, leading to reduction of their number and the loss of cell motility