Biosynthetic pathway and physiological role of pyruvylated galactose-containing oligosaccharides in fission yeast.

在裂殖酵母裂殖酵母中，半乳糖残基通过高尔基体内腔中的半乳糖基转移酶转移到糖蛋白的N-和O-连接的寡糖。细胞表面糖蛋白在酵母的絮凝和丝状侵入生长中起着关键作用。我们确定了裂殖酵母gsf 2+，编码一种絮凝蛋白，它与位于细胞表面糖复合物上的半乳糖残基结合。絮凝和侵入生长的S。粟酒裂殖酵母受GSF 2+表达的严格控制。MADS盒转录因子Mbx 2通过诱导gsf 2+表达调节无性絮凝。S.粟酒裂殖酵母似乎具有独特的半乳糖特异性识别系统，其中Gsf 2 p/絮凝蛋白在介导细胞-细胞相互作用中起重要作用。此外，我们还刻画了一个假定的S。粟酒裂殖酵母乙酰基转移酶Pvg 1 p和重组Pvg 1 p将乙酰基残基从磷酸烯醇丙酮酸特异性转移到β-连接的半乳糖。

In the fission yeast Schizosaccharomyces pombe, galactose residues are transferred to N- and O-linked oligosaccharides of glycoproteins by galactosyltransferases in the lumen of the Golgi apparatus. Cell surface glycoproteins play a key role in flocculation and filamentous invasive growth in yeasts. We identified fission yeast gsf2+, encoding a flocculin that binds to galactose residues located on cell surface glycoconjugates. Flocculation and invasive growth of S. pombe is tightly controlled by gsf2+ expression. MADS-box transcription factor Mbx2 regulates nonsexual flocculation by inducing gsf2+ expression. S. pombe appears to have a unique galactose-specific recognition system in which Gsf2p/flocculin plays an essential role in mediating cell-cell interactions. Furthermore, we characterized a putative S. pombe pyruvyltransferase, Pvg1p, and the recombinant Pvg1p transferred pyruvyl residues from phosphoenolpyruvate specifically to beta-linked galactose.