engleski

Proteolytic processing of Saccharomyces cerevisiae cell wall proteins Scw4p and Scw10p

Yeast cell wall contains proteins that are noncovalently (Scw-proteins) or covalently (Ccw-proteins) bound to β-1, 3-glucan, the latter either through GPI-anchors and β-1, 6- glucan, or by alkali labile ester linkages between γ-carboxyl groups of glutamic acid and hydroxyl groups of glucoses (Pir-proteins, extracted from the cell wall by mild alkali). It was previously shown that one of the most abundant Scw protein, Scw4p is partly also covalently linked to the cell wall, as well as it’s homolog Scw10p. In this work it was shown that part of Scw4p and Scw10p underwent the proteolytic processing resulting in three forms of the protein in the cell wall. The proteolytic enzymes which might have a role in processing of Scw4p and Scw10p are Kex2p and a family of aspartic proteases called yapsins. To get a better insight in the processing of these proteins, different mutations were introduced to SCW4 in the region of predicted processing sites. Native and mutated forms of Scw4p were expressed in kex2 yeast strain and strain with all yapsin genes disrupted (5yps∆) and Scw4p processing was examined. Protein glycosilation was also examined in order to determine whether forms differ in this way.

yeast cell walls; cell wall proteins; Scw4p; Scw10p; Kex2p

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