Scott J. Hultgren

Molecular escorts required to present bacterial adhesins to eukaryotic receptors

Presentation of bacterial adhesins to eukaryotic receptors facilitates bacterial attachment and colonization of host mucosal surfaces and in many cases the subsequent invasion of these tissues (Schoolnik et al., 1987; Williams et al., 1988; Hultgren et al., 1989). Microbial attachment and colonization allow bacteria to survive the mechanical cleansing of mucosal surfaces. Heteropolymeric surface fibers called pili on bacteria often mediate microbial attachment (Normark et al., 1986; Williams et al., 1988; Hultgren et al., 1989; Hultgren et al., 1991a). The adhesins which mediate binding are typically minor components of pili, often located at their distal tips (Hultgren et al., 1985; Abraham et al., 1988). We describe here some of the molecular details on how Gram negative bacteria assemble adhesive fibers and how adhesins are correctly presented in these fibers so that they can recognize receptors on eukaryotic epithelial cell surfaces to promote microbial attachment. P pilus biogenesis is used as a prototype system to investigate how protein subunits fold into domains that serve as assembly modules for building adhesive pili on the surface of bacteria.