Protein folding and localization in the cell

这个项目的最终目的是了解新合成的蛋白质在获得生物功能结构和细胞内定位的过程中遵循的原理和途径。合作研究的更具体目标是促进积极参与这一快速发展领域的研究人员之间的信息交流和合作。以下是结果的简要总结。由此得到的结果表明，蛋白质的“熔融球状”结构是在生理条件下发生的。尤拉在大肠杆菌的热休克反应中发现了一种翻译调节机制，并鉴定了大肠杆菌热休克蛋白的几种生理功能。香川从一种嗜热细菌中鉴定出热休克基因和蛋白质。Yahara发现了Hsp90‘S在核受体-细胞骨架相互作用以及Hsp90-酪蛋白激酶II复合体中的作用。Kohno确认了Huma XPAC同源物上携带的核目标信号。水岛重新启动…从大肠杆菌SecA、SecY和SecE中分离出更多的蛋白质易位，并剖析了蛋白质分泌的信号序列。ITO鉴定了对催化和SEC复合体形成重要的SecY结构域，以及作用于二硫键形成的周质折叠因子(PPFA)。Amaya鉴定了SRP亚单位54的酵母同源物，并表明它参与了蛋白质向内质网的转运。Sakaguchi指出，电荷分布和疏水性是蛋白质插入ER膜取向的主要决定因素。远藤构建了一个系统来监测线粒体前体蛋白在易位过程中的构象变化。OSumi发现了一个可切割的N-末端信号，用于靶向3-酮酰辅酶A硫解酶的过氧酶体。Mizunaga克隆了酵母蛋白二硫键异构酶基因，并对其进行了测序，结果表明该基因对酵母的生存是必需的。吉森发现，在大鼠外分泌泛分泌细胞中可以分泌一些内质网驻留蛋白。Hirayoshi确定了Hsp47基因，并提出Hsp47是一种胶原蛋白特异性伴侣。Nakano证明，酵母中SarIP的GTPase活性是内质网向高尔基蛋白运输所必需的，可能是在囊泡形成之后的一个步骤。对酵母菌Bip进行了纯化和鉴定。较少

The ultimate aim of this project is to understand the principles and the pathway that newly synthesized proteins of follow in their process of acquisition of biologically functional structure and localization within the cell. More specific objective of this Cooperative Research is to stimulate information exchange and collaborations among researchers actively involved in this rapidly developing field. Following are brief summaries of the results.Goto obtained results that suggest"molten globule"structure of proteins occurs under physionlogical conditions. Yura discovered a translational regulation in the heat shock response of E. coli and identified several physiological functions of E. coli Hsps. Kagawa identified heat shok genes and proteins from a thermophilic bacterium. Yahara discovered Hsp90's role in nuclear-acting receptor-cytoskeleton interactions as well as Hsp90-casein kinase II complex. Kohno identified nuclear targeting signal carried on huma XPAC homolog. Mizushima recost … More ituted protein translocation from SecA, SecY and SecE of E. coli and dissected signal sequences for protein secretion. Ito identified SecY's domains important for calalysis and Sec complex formation, as well as a periplasmic folding factor (PpfA) acting at the disulfied bond formation. Amaya identified a yeast homolog of SRP subunit 54 and showed that it is involved in protein translocation into ER. Sakaguchi showed that charge distribution and hydrophobicity are major determinants of the orientation in protein insertion into ER membrane. Endo constructed a system to monitor conformational changes of a mitochaondrial precursor protein during translocation. Osumiidentified a cleavable N-terminal signal for targeting of 3-ketoacyl-CoA thiolase to peroxisomes. Mizunaga cloned and sequenced the yeast protein disulfide isomerase gene and showed that it is essential for viability. Yoshimori showed that some ER resident proteins can be secreted in rat exocrine pancreative cells. Hirayoshi determined the Hsp47 gene and proposed that Hsp47 is a collagen-specific chaperone. Nakano showed that the GTPase activity of SarIP in yeast is required for ER to Golgiprotein transport probably at a step subsequent to vesicle formation. Tokunaga purified and characterized yeast BiP. Less