engleski

The role of Scw4p in yeast cell wall biogenesis

The cell wall of the yeast S. cerevisiae has a bilayered structure. The inner part of the wall consists mainly of b-1, 3-glucan, and the outer layer is composed mostly of mannoproteins. Yeasts have evolved three different ways of attaching proteins to glucan. Some proteins are bound noncovalently, while others are attached covalently through GPI-anchor and  -1, 6-glucan, or directly to  -1, 3-glucan by a mechanism still not completely understood (Pir-proteins ; extracted from the wall by NaOH). Exact physiological role for most cell wall proteins is still unknown. 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 from the extract, indicating that Scw4p could also be covalently linked to the cell wall simillar to Pir-proteins. Since it was reported previously that Scw4p was a noncovalently attached protein, this finding can be relevant for the role of Scw4p. In order to investigate the role of the Scw4p in the construction of the cell wall, yeast was transformed with a high copy number plasmid containing SCW4. Phenotypes of this strain as well as scw4, ccw5ccw6ccw7ccw8 and ccw5ccw6ccw7ccw8scw4 were examined.

yeast; cell wall; cell wall proteins

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