GLYCOPROTEIN PROCESSING SYSTEMS OF ER AND GOLGI

我们对酶系统的结构和功能感兴趣 内质网中的糖基化蛋白及其过程 高尔基体中的糖蛋白碳水化合物单位。正在研究的ER系统 包括多酚磷酸甘露糖合成酶和酵母菌ALG 催化合成内质网二醇连接的蛋白质 低聚糖。这种低聚糖被转移到特定的 新生多肽链进入内质网时的天冬酰胺残基 流明。最近已有三个ALG基因被克隆和测序。我们是 对结构和功能的相互作用特别感兴趣 这些酶。我们将应用“合成致死”等技术。 分离参与这些相互作用的蛋白质的基因的方法。 正在研究的高尔基体糖蛋白处理系统包括一系列 酵母菌甘露糖醇转移酶与GDPase 将核苷酸糖运入高尔基体腔的过程。转移酶 将以生化为特征，而基因突变需要 维持细胞活力的GDPase将通过 合成致死方法。我们还将探索一种新发现的mnn9 编码蛋白质的基因家族，这些蛋白质可能是许多 重要的高尔基函数。 由于这些系统中有几个显然是“非哺乳动物”的，它们也将 作为致病酵母菌潜在药物靶点的研究 白念珠菌。我们已经有关于假丝酵母菌甘露醇转移酶的数据 有念珠菌mnn9同源物的基因片段。这些基因将是 和产生的菌株将在一种 老鼠模型。其他念珠菌研究的目的是描述基因和 参与细胞壁β-甘露糖醇残基合成的酶 这可能在生物体的致病性中发挥作用。

We are interested in the structure and function of enzyme systems that glycosylate proteins in the endoplasmic reticulum (ER) and that process glycoprotein carbohydrate units in the Golgi. ER systems under study include dolichol phosphate mannose synthase and the Saccharomyces ALG proteins which catalyze synthesis of the ER dolichol linked oligosaccharide. This oligosaccharide is transferred to specific asparagine residues of nascent polypeptide chains as they enter the ER lumen. Three ALG genes have recently been cloned and sequenced. We are especially interested in the structural and functional interaction among these enzymes. We will apply techniques such as the "synthetic lethal" approach to isolate genes for proteins involved in these interactions. Golgi glycoprotein processing systems under study include a family of Saccharomyces mannosyl transferases and the GDPase which plays a role in the transport of nucleotide sugars into the Golgi lumen. The transferases will be characterized biochemically, and mutations in genes which require the GDPase for maintenance of cell viability will be isolated by the synthetic lethal method. We will also explore a newly discovered mnn9 gene family which encodes proteins which may be required for a number of important Golgi functions. Since several of these systems are clearly "non-mammalian", they will also be studied as potential drug targets in the pathogenic yeast Candida albicans. We already have data on the Candida mannosyl transferases and have gene fragments from Candida mnn9 homologs. These genes will be "knocked out" and resulting strains will be tested for pathogenicity in a mouse model. Other Candida studies are aimed at characterizing genes and enzymes involved in the synthesis of the cell wall beta-mannosyl residues that may play a role in pathogenicity of the organism.