Multifunctional Cytoadherence Factors
Miriam Hopfe and Birgit Henrich
from: Mollicutes: Molecular Biology and Pathogenesis (Edited by: Glenn F. Browning and Christine Citti). Caister Academic Press, U.K. (2014)
In the cell-wall-less Mollicutes cytoadherence factors that enable tight contact with the host often play additional roles in colonisation, nutritional uptake and the host's immune response. Multifunctional cytoadhesins have been shown to interact with components of the extracellular matrix facilitating invasion of the host, and to hamper a successful immune response by through antigenic variation, mimicy or release of antigens into their surroundings. Cytoadhesins that condense at a tip structure in some species are also involved in gliding motility. Detailed sequence analyses have enabled the detection of six mycoplasmal cytoadhesive moonlighters that are characterised by the independence of their different functions. Heparin binding of P97 and P110 of M. hyopneumoniae was shown to be mediated by regions distinct from their cytoadhesive domains. The α-enolase of M. gallisepticum acts at different locations, intracellularly as a cytoplasmic glycolytic enzyme and surface-exposed as an ECM-binding cytoadhesin. Antigenic mimicry of P1 and P30 are unique features of these proteins in M. pneumoniae, in contrast to their homologous in other mycoplasmas. The most outstanding moonlighter described thus far is OppA of M. hominis: it mediates cytoadherence, functions as peptide-binding domain for the oligopeptide permease and is the main ecto-ATPase, the action of which leads to apoptotic death in host cells. Phosphorylation appears to be one mechanism enabling coordinated cooperation between these distinct functions in a multifunctional cytoadhesin read more ...