MECHANICS AND FUNCTIONS OF THE N-END RULE PATHWAY

描述：泛素是一种76个残基的蛋白质，存在于细胞中， 游离或与许多其他蛋白质结合。 选择性降解 蛋白质通过泛素/蛋白酶体依赖性途径发挥作用， 许多生物过程，包括细胞生长和 分化、信号转导和对胁迫的响应。 一 泛素/蛋白酶体依赖的蛋白水解系统是N-末端规则途径， 实验室于1986年。 N-末端规则将体内 蛋白质的半衰期与其N-末端残基的身份有关。 n端 规则途径存在于从哺乳动物到细菌的所有生物体中。 由现时拨款资助的研究项目（“机械及功能 N-end Rule Pathway”，DK 39520），目前已进入第11个年头， 对N端规则的功能和机制的重要见解， 在进度报告中描述。 研究的目的是描述 在这个更新申请中， 规则途径和泛素系统的相关方面。 具体目标 1）通过N-末端规则途径调节肽输入： 生物化学和遗传学研究; 2）基于融合的生理筛选 S中N端规则途径的底物。酿酒酵母; 3）分离和 N-末端规则途径的调节子分析; 4）突变体的筛选 其生存力需要N-末端r的存在; 5）使用 抑制性消减杂交鉴定N端的新功能 规则途径; 6）Ntalp的线粒体功能分析 N-末端酰胺酶。7）一种生物化学遗传学方法， 鉴定生理N-末端规则底物; 8）“双头” N-末端规则途径的抑制剂; 9）“双泛素”技术和 其在共翻译蛋白质水解问题上的应用;和10） UBRI编码的Nrecognin和Ubr 2 p的生化和遗传解剖， 最近在S.啤酒。

DESCRIPTION: Ubiquitin is a 76-residue protein that exists in cells either free or conjugated to many other proteins. Selective degradation of proteins by the ubiquitin/proteasome-dependent pathways plays a role in a multitude of biological processes, including cell growth and differentiation, signal transduction and responses to stress. One ubiquitin/proteasome-dependent proteolytic system is the N-end rule pathway, identified by the laboratory in 1986. The N-end rule relates the in vivo half-life of a protein to the identity of its N-terminal residue. The N-end rule pathway is present in all organisms examined, from mammals to bacteria. Studies supported by the present grant ("Mechanics and Functions of the N-end Rule Pathway", DK39520), currently in its 11th year, have yielded significant insights into the N-end rule's functions and mechanisms, as described in the Progress Report. The objective of the research described in this renewal application is to advance the understanding of the N-end rule pathway and related aspects of the ubiquitin system. Specific aims are: 1) Regulation of peptide import by the N-end rule pathway: biochemical and genetic studies; 2) A fusion-based screen for physiological substrates of the N-end rule pathway in S. cerevisiae; 3) Isolation and analysis of regulators of the N-end rule pathway; 4) Screens for mutants whose viability requires the presence of the N-end r; 5) The use of suppression subtractive hybridization to identify new functions of the N-end rule pathway; 6) Analysis of a mitochondrial function of the Ntalp N-terminal amidase in S. cerevisiae; 7) A biochemico-genetic approach to identification of physiological N-end rule substrates; 8) A "double-headed" inhibitor of the N-end rule pathway; 9) The "two-ubiquitin" technique and its application to the problem of cotranslational proteolysis; and 10) Biochemical and genetic dissection of the UBRI-encoded Nrecognin and Ubr2p, a recently identified homolog of Ubrlp in S. cerevisiae.