Naslov
Localisation and physiological role of yeast cell wall proteins

Autori
Mrša, Vladimir ; Teparić, Renata ; Stuparević, Igor

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Abstracts of the 14th International Congress of the Hungarian Society for Microbiology / Hungarian Society for Microbiology - Balatonfuered : Hungarian Society for Microbiology, 2003

Skup
14th International Congress of the Hungarian Society for Microbiology

Mjesto i datum
Balatonfüred, Mađarska, 09.10.2003. - 11.10.2003

Vrsta sudjelovanja
Pozvano predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
yeast S. cerevisiae; cell wall proteins

Sažetak
Yeast cell wall is composed of structural polysaccharides, glucan, mannan and chitin, and a number of glycoproteins. S. cerevisiae wall mannoproteins can either be noncovalently (Scw proteins-soluble cell wall proteins), or covalently (Ccw proteins-covalently linked cell wall proteins) bound to glucan. Scws are released from the wall by hot SDS, while Ccws are usually extracted by glucanases although a group of them (so called Pir-proteins with internal repeats) can also be released from glucan by mild alkali treatment. Different extraction methods reflect differences in localisation mechanisms of the three groups of proteins. For Scws no enzymatic attachment to wall polysaccharides was postulated and the adsorption may simply be due to chemical properties of beta-1, 3 glucan which reacts with many proteins by hydrogen bonding. Most glucanase-extractable proteins share the localisation mechanism involving the binding of C-terminally attached GPI-anchor to beta-1, 6-glucan, while the Pir-protein family is anchored to beta-1, 3-glucan by a so far unexplained reaction involving the characteristic repetitive sequence of these proteins. In order to assess their possible physiological role, mutants were constructed by disruption of different genes coding for cell wall proteins like SCW4, SCW10, SCW11, and SCW8/BGL2, as well as all four known PIR genes (CCW5, CCW6/PIR1, CCW7/PIR2/HSP150, and CCW8/PIR3). All mutants were viable and did not require osmotic stabilisers. However, some of them, like scw4scw10 and scw4scw10bgl2, showed significantly increased fraction of dead cells in the culture. Interestingly, additional scw11 mutation suppressed the observed phenotype indicating an antagonistic behaviour of Scw11p to Scw4p, Scw10p and Bgl2p. In agreement with this, it was also found that scw4scw10 secretes less proteins into the growth medium, which was also reversed by an additional scw11 mutation. Successive mutations of PIR genes led to changes in cell morphology and stability and also to increased mortality. Young cells seem to be more affected. Microscopic investigation showed an increased fraction of cells with more than one bud and in most cases daughter cells still attached to their mothers stained with methylene blue. Some potential medical and biotechnological applications of the obtained results will be discussed.

Izvorni jezik
Engleski

Znanstvena područja
Biotehnologija

POVEZANOST RADA