Stochastic Modeling of Protein Interactions in the Endoplasmic Reticulum

描述(由申请人提供)：大多数细胞功能是由蛋白质-蛋白质相互作用调节的。对这些相互作用的控制是通过蛋白质活性的特异性直接实现的，并通过与伴侣辅助因子的选择性相互作用间接实现。传统上，瞬时相互作用的定量数据来自体外试验，在体外试验中，配对蛋白的相互作用与其他细胞因子分离。当将这些数字外推到活体条件时，通常假设蛋白质环境是均一的。然而，很明显，这些相互作用的动态性质创造了细胞器下的蛋白质池。复杂的异质环境对细胞功能的动态影响还没有得到充分的量化，其中蛋白质伙伴的局部浓度将不同于他们在细胞内的整体浓度。 这项研究计划集中在这些局部环境对细胞蛋白质折叠细胞器内质网(ER)活动的影响。利用新兴的定量荧光显微镜技术、数学建模和酵母遗传学的组合，拟议的研究将定量确定常驻ER HSP70伴侣蛋白Bip的蛋白质-蛋白质相互作用对其定位和功能的作用。蛋白质的错误折叠和蛋白质不能穿过分泌的早期步骤与糖尿病、囊性纤维化和几种神经疾病有关。这项提议将生物科学家和工程师结合在一起，以发展对细胞网络的基本理解，并创建一种解释分泌缺陷的方法。此外，这项研究将提供对分泌过程中重要的特定细胞功能的洞察，这些功能已经很难通过传统的生化方法来解决。

DESCRIPTION (provided by applicant): The majority of cellular functions are mediated by protein-protein interactions. Control of these interactions Is achieved directly from specificity of protein activity and indirectly though selective interactions with partner co-factors. Traditionally quantitative data on transient interactions comes from an in vitro assay where the interactions of partner proteins are isolated from other cellular factors. When extrapolating these numbers to in vivo conditions it is usually assumed that the protein milieu is homogenous. Yet it is clear that the dynamic nature of these interactions creates suborganellar pools of proteins. The dynamic effect of complex heterogeneous environments on cellular function has not been adequately quantitated, where local concentrations of protein partners will be different from their overall concentration in the cell. This research proposal focuses on the effects of these localized environments on the action of the cellis protein folding organelle, the endoplasmic reticulum (ER). Utilizing a combination of emerging quantitative fluorescent microscopy techniques, mathematical modeling and yeast genetics, the proposed research will quantitatively determine the role of the protein-protein interactions of BiP, the resident ER hsp70 chaperone, on its localization and function. Improperly folded proteins and the failure of proteins to traverse the early step of secretion is linked to diabetes, cystic fibrosis, and several neurological diseases. This proposal integrates biological scientists with engineers to develop a fundamental understanding of cellular networks and create a methodology to explain deficiencies in secretion. In addition, this research will provide insight to specific cellular functions important for the secretory process that have been difficult to address by traditional biochemical methods.