engleski

Role and localization of Scw4p in Saccharomyces cerevisiae cell wall

In the Saccharomyces cerevisiae cell wall more than 20 different mannoproteins were evidenced. They are considered to play different roles in building, maintaining and modifying the wall itself during growth and different cell cycle events and they are important for interactions of cells with their surrounding. Yeasts have evolved three different ways of attaching proteins to cell wall glucan. Some proteins are bound to β -1, 3-glucan noncovalently (Scw – soluble cell wall proteins ; extracted by hot SDS), while others are attached covalently (Ccw – covalently linked cell wall proteins ; extracted by glucanases) through GPI-anchor and β -1, 6-glucan, or directly to β -1, 3-glucan by alkali labile ester linkage between the γ -carboxyl groups of glutamic acid and hydroxyl groups of glucoses (Pir – proteins with internal repeats ; extracted by NaOH). Disruption of genes coding for the Pir-proteins was performed to investigate their potential role. After disruption of all PIR genes, 67kDa protein still remained in NaOH extract. SCW4 disruption resulted in disappearance of a 67kDa band, indicating that Scw4p could also be covalently linked to the cell wall similar to Pir-proteins. Since it was reported previously that Scw4p was a noncovalently attached protein, this finding could be relevant for the role of Scw4p. In order to get insight in binding to glucan Scw4p was tagged and its localization in different mutants was studied. Besides, effects of different levels of synthesis of Scw4p, as well as its homologs Scw10p and Scw11p on yeast phenotype was studied to investigate their physiological roles.

SCW4; yeast cell wall; Scw proteins

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