engleski

Alkali-extractable proteins in Saccharomyces cerevisiae cell wall

Yeasts have evolved three different ways of attaching proteins to cell wall. Some proteins are bound noncovalently to the β -1, 3-glucan, while others are attached covalently to the β -1, 6-glucan through a GPI-anchor, or directly by alkali labile ester linkage between the γ -carboxyl group of glutamic acid and the hydroxyl group of glucose (named as Pir – proteins). Different mutants lacking individual wall proteins or groups of proteins were constructed and their phenotypes were studied. After disruption of all the PIR genes, a 67kDa protein still remained in NaOH extract. SCW4 disruption in the ccw5ccw6ccw7ccw8 mutant, however, resulted in disappearance of the 67kDa band from the extract, indicating that Scw4p could also be covalently linked to the cell wall. Since it was reported previously that Scw4p was a noncovalently attached protein, this finding can be relevant for the role of Scw4p. A mild treatment of yeast cells with β -glucanase induced a drastic decrease in the cell surface hydrophobicity indicating that it is at least to a great extent due to mannoproteins of the outer layer of the cell wall. This phenomenon together with the obvious assumption that the outermost located mannoproteins play crucial role in the cell-cell interaction during film formation motivated us to screen for the differences in cell wall protein composition between film forming and non-film forming strains in order to get a better insight into the interactions during cell attachment.

yeast; cell wall; Pir proteins; SCW4; biofilm

nije evidentirano