Defense Mechanism of cells from stresses

1-1.我们发现热休克蛋白90可以结合并保护变性的萤火虫荧光素酶不可逆的聚集。当在HSP 70、HSP 40和网织红细胞裂解物中含有的另一种分子伴侣中后孵育时，荧光素酶可以从复合物中释放。我们发现HSP 90 N端特异性单克隆抗体可与HSP 90二聚体的两端结合。这表明HSP 90单体以反平行方式并排排列，并通过其C末端形成二聚体。在芽殖酵母中，发现Hsc 82的表达水平与胁迫耐受性的程度可逆地成比例。我们用核磁共振法测定了一种与cofilin相关的蛋白质destrin的三级结构，其结构类似于凝溶胶蛋白的单一片段。该结构为cofilin与肌动蛋白的Ca^<2+>非依赖性结合提供了分子基础。在网骨藻细胞中过表达cofilin可诱导大量的肌动蛋白束。这被认为是由cofilin诱导的F-肌动蛋白的切断从肌动蛋白网络到束的转化的结果。我们进一步证明，束收缩响应渗透胁迫。2 -3。我们发现cofilin因Ser-32-4的磷酸化而失活。在酿酒酵母中分离到一个cofilin-ts突变体的多拷贝抑制子。抑制基因SCF 1编码WD 40重复蛋白，其与先前描述为肌动蛋白相互作用蛋白的Aip 1相同。SCF 1对细胞活力不是必需的。2 -5.已经获得的生物化学证据表明，网骨藻Aip 1与F-肌动蛋白结合，并通过cofiin将其破坏。

1-1. We found taht heated HSP90 binds and protects denatured firefly luciferase from irreversible aggregation. Luciferase can be released from the complexes when post-incubated in HSP70, HSP40 and another chaperone contained in reticulocyte lysate.1-2. We found taht monoclonal antibodies specific to the N-terminus of HSP90 bound to both ends of HSP90 dimers. This indicates that HSP90 monomers align side-by-side in an antiparallel fashion and form dimers through their C-termini.1-3. In the budding yeast, the expression level of Hsc82 was found to be reversibly proportional to the degree of stress tolerance.2-1. We have determined tertiary structure of destrin, a cofilin-related protein, by NMR.The structure is similar to that of a unitary segment of gelsolin. The structure provides molecula basis for Ca^<2+> -independent binding of cofilin to actin.2-2. Overexpression of cofilin in Dictyostelium cells induced a number of actin bundles. This was suggested to be a result of transformation from actin meshwork to bundles by cofilin-induced severing of F-actin. We further demonstrated that the bundles contracted in response to osmotic stress.2-3. We found that cofilin was inactivated by phosphorylation of the Ser-32-4. A multicopy suppressor to a cofilin-ts mutant in Saccharomyces cerevisiae was isolated. The suppressor gene SCF1 encodes a WD40-repeat protein which is identidal to Aip1 previously described as an actin-intereating protein. SCF1 is not essential for cell viability.2-5. Biochemical evidence has been obtained that Dictyostelium Aip1 binds to F-actin and seisitizes it to destruction by cofiin.