GLYCOPROTEIN PROCESSING SYSTEMS OF ER AND GOLGI

我们感兴趣的是酶系统的结构和功能， 内质网（ER）中的糖基化蛋白， 高尔基体中的糖蛋白碳水化合物单位。 研究中的ER系统 包括多萜醇磷酸甘露糖合酶和酵母属ALG 催化ER多萜醇合成的蛋白质 低聚糖。 这种寡糖被转移到特定的 新生多肽链进入内质网时的天冬酰胺残基 流明 最近，三个ALG基因已被克隆和测序。 我们 尤其是在结构和功能的相互作用， 这些酶。 我们将使用“合成致命”等技术 方法来分离参与这些相互作用的蛋白质的基因。 正在研究的高尔基体糖蛋白加工系统包括一个家族， 酵母甘露糖基转移酶和GDPR，其在 将核苷酸糖运输到高尔基体腔中。 转移酶 将以生物化学为特征，基因突变需要 用于维持细胞活力的GDPR将通过 合成致死法 我们还将探索新发现的mnn 9 编码蛋白质的基因家族，所述蛋白质可能是许多 高尔基体的重要功能 由于这些系统中有几个显然是“非哺乳动物”的，它们也将 作为潜在的药物靶点在致病酵母念珠菌中进行研究 白色念珠菌 我们已经有了念珠菌甘露糖转移酶的数据， 有念珠菌mnn 9同源物的基因片段 这些基因将 “敲除”和产生的菌株将在一个 小鼠模型 其他念珠菌研究的目的是表征基因， 参与细胞壁β-甘露糖残基合成的酶 这可能在病原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.