engleski

Yeast cell wall glycoproteins: detection-structure-function

Recently it has been shown that the PMT gene family is responsible for protein-O-mannosylation in S. cerevisiae and that certain triple pmt disruptions are lethal. Other multiple disruptions could be saved, if the cells were osmotically stabilized indicating that protein O-glycosylation is required for cell wall integrity. To understand this phenomenon, it was decided to analyze and characterize the complete set of yeast cell wall proteins. Using non-permeant biotinylation more than 20 cell surface proteins could be specifically labeled. More than 10 of them seem to be covalently linked within the wall, the rest can be extracted by SDS under reducing conditions. After purification and N-terminal sequencing, ten new cell wall components have been identified besides the known gene products of EXG1, CTS1, BGL2. Among the new ones are 4 PIR gene products (proteins with internal repeats) and 3 glucanases or glucanase related proteins. Single gene disruptions of these genes do not give rise to conspicuous phenotypes, multiple ones partly do. Evidence has been obtained that almost all of these cell wall proteins are O-glycosylated.

Saccharomyces cerevisiae; yaest cell wall; glycoproteins

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