STRUCTURE-FUNCTION RELATIONSHIPS OF LYSOSOMAL ENZYMES

溶酶体酶的结构-功能关系

• 批准号: 3855397
• 负责人: R L PROIA
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3855397
• 关键词: Tay Sachs disease; beta N acetylhexosaminidase; chemical aggregate; endoplasmic reticulum; enzyme mechanism; enzyme structure; gangliosidosis; gene deletion mutation; gene expression; gene mutation; genetic mapping; glycosylation; human population genetics; human tissue; lysosomes; molecular cloning; nucleic acid sequence; protein structure function; tissue /cell culture

I. The Moroccan Jewish population has an elevated incidence of Tay-Sachs disease. We have examined 6 unrelated Moroccan carriers of the disease and have identified three HEXA gene mutations: (1) a Leu(181)->Stop mutation in one carrier, (2) an Arg(170)->Glu change in two of the carriers and (3) an in-frame deletion of a phenylalanine codon at position 304 (delta-F) in three of the carriers. II. The complete organization of the murine HEXB gene and the majority of the HEXA gene has been established. This has allowed the construction of gene targeting vectors for the purpose of "knocking out" the HEX genes in mouse embryonic stem cells and for ultimately producing mouse models of the G(M2) gangliosidoses. III. Mechanisms by which normal and abnormal proteins are retained in the endoplasmic reticulum (ER) have been determined. The protein signals that specify whether members of a family of carboxylesterases are secreted or retained in the ER have been identified. These retention signals are variants of the yeast signal (HDEL) previously thought not to function in mammalian cells. We have also found that the unglycosylated alpha-subunit of beta- hexosaminidase undergoes an altered folding pathway resulting in the formation of an insoluble, inappropriately disulfide-bonded aggregate that is retained in the ER. The inappropriately folded protein is bound to BiP/GRP 70 which acts as a molecular scaffold in ER.

I. 摩洛哥犹太人群体的泰-萨克斯病发病率较高 疾病 我们已经检查了6个无关的摩洛哥疾病携带者， 已经鉴定了三种HEXA基因突变：（1）Leu（181）->Stop突变 在一个载体中，（2）在两个载体中Arg（170）->Glu变化，和（3） 在304位（delta-F）的苯丙氨酸密码子的框内缺失， 三个运营商。 二. 小鼠HEXB基因的完整组织和大多数 HEXA基因已被确定。 这使得建造 用于“敲除”HEX基因的基因靶向载体， 小鼠胚胎干细胞，并最终产生小鼠模型， G（M2）神经节苷脂沉积症。 三. 正常和异常蛋白质保留在细胞中的机制 内质网（ER）的变化。 这种蛋白质发出信号， 说明羧酸酯酶家族的成员是否分泌或 在急诊室里，已经找到了。 这些保留信号是 酵母信号的变体（HDEL）以前被认为在 哺乳动物细胞 我们还发现，β-淀粉样蛋白的非糖基化α-亚基， 氨基己糖苷酶经历改变的折叠途径， 形成不溶性的、不适当的二硫键结合的聚集体， 留在急诊室 不适当折叠的蛋白质与 BiP/GRP 70在ER中充当分子支架。