CONSTITUTIVE STRESS PROTEINS AND STRESS TOLERANCE

组成性应激蛋白和应激耐受性

• 批准号: 6328958
• 负责人: Michael Jude Borrelli
• 金额: $ 18.4万
• 依托单位: WILLIAM BEAUMONT HOSPITAL RESEARCH INST
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-12-09 至 2002-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6328958
• 关键词: conformation; crosslink; crystallins; cytotoxicity; microinjections; molecular chaperones; phosphorylation; protein biosynthesis; protein denaturation; protein folding; protein structure function; proteolysis; stress proteins; tissue /cell culture

Stress induces cells to develop Tolerance against subsequent exposure to a diverse range of toxic insults. There are two phases of Tolerance. One phase develops quickly and requires no protein synthesis (protein synthesis independent Tolerance: PSIT). Stress-induced protein synthesis is requisite for the slower developing, more protracted second phase (protein synthesis dependent Tolerance: PSDT). The central hypothesis is that heat shock proteins (HSPs) confer PSIT and PSDT stress protection. We proposed a model in which stress-denatured and aggregated proteins induce cells to develop PSIT and/or PSDT. PSIT develops more quickly and requires constitutively expressed HSP-27 and/or alphaB-crystallin to maintain stress-denatured and aggregated proteins in a folding competent state, making the proteins more accessible to disaggregation by the unfolding/refolding chaperone activity of HSC-70 and/or HSP-70. If PDT is also induced, PSIT protects cells while additional HSP-27, alphaB-crystallin and HSP-70/HSC-70 are synthesized. Up-regulated HSPs then provide protracted PSDT protection after PSIT decays. In both PSIT and PSDT, HSC70 and/or HSP 70 ultimately disaggregate large protein aggregates into smaller ones. Proteins in the smaller aggregates are either returned to their native state by continued HSC-70 or HSP-70 unfolding/refolding, or more efficiently proteolyzed. The specific aims and experimental design will test critical aspects pf the model by determining how PSIT and PSDT are induced, and how HSP-27 and alphaB-crystallin confer PSIT and PSDT stress protection. This will include determining how stress-induced: phosphorylation, changes in oligomer size, and changes in cellular distribution of HSP-27 and alphaB- crystallin influence their stress protection. Experiments will also establish if HSP-27 and alphaB-crystallin function in a cooperative manner with HSC-70 and HSP-70 to provide stress protection, and discover the conditions that determine whether denatured proteins are disaggregated into a soluble state of proteolyzed. Tolerance provides protection against many clinically relevant stresses, e.g., ischemia, and denatured and abnormal proteins are involved in many human diseases including, Alzheimer's disease. Thus, understanding how HSPs function in PSIT and PSDT to protect cells against cytotoxic stresses and to ameliorate the cytotoxicity of denatured and aggregated proteins may lead to new and effective clinical applications for stress Tolerance.

压力会诱导细胞发展耐受性，以防止随后暴露于 多种有毒侮辱。宽容有两个阶段。一 阶段很快发展，不需要蛋白质合成（蛋白质 综合独立公差：PSIT）。应激诱导的蛋白质合成 对于较慢的发展，更持久的第二阶段是必需的 （蛋白质合成依赖性耐受性：PSDT）。 中心假设是热休克蛋白（HSP）赋予PSIT和 PSDT应力保护。我们提出了一个模型，其中压力镇定和 聚集的蛋白质会诱导细胞发展PSIT和/或PSDT。 PSIT 开发更快，需要组成表达的HSP-27和/或 α-晶状体蛋白以维持压力定位和聚集的蛋白质 折叠能力的状态，使蛋白质更容易获得 通过HSC-70的展开/重折叠伴侣活性进行分解 和/或HSP-70。如果还诱导了PDT，则PSIT可以保护细胞，而 合成了其他HSP-27，Alphab-Crystallin和HSP-70/HSC-70。 然后上调HSP，然后在PSIT之后提供持久的PSDT保护 腐烂。在PSIT和PSDT中，HSC70和/或HSP 70最终分类 大蛋白聚集成较小的蛋白质。较小的蛋白质 骨料要么通过续HSC-70返回其祖国状态 或HSP-70展开/重折叠，或更有效地蛋白水解。 具体目的和实验设计将测试关键方面PF 通过确定PSIT和PSDT的诱导以及HSP-27和HSP-27和 Alphab-crystallin授予PSIT和PSDT应力保护。这会 包括确定应力诱导的方式：磷酸化，变化 低聚物大小，以及HSP-27和字母的细胞分布的变化 结晶蛋白会影响他们的压力保护。实验也将 确定HSP-27和Alphab-Crystallin是否以合作的方式功能 使用HSC-70和HSP-70提供压力保护，并发现 确定变性蛋白是否分解的条件 进入蛋白水解的可溶性状态。 耐受性提供了针对许多临床相关压力的保护， 例如，缺血，变性和异常蛋白参与了许多 人类疾病，包括阿尔茨海默氏病。因此，了解如何 HSP在PSIT和PSDT中的功能可保护细胞免受细胞毒性应力 并改善变性和聚集的蛋白质的细胞毒性 可能会导致新的有效的临床应用应耐心。