CYTOHESIN-1 PH DOMAIN AND CELLULAR ADHESION

双光子激光扫描显微镜、荧光光谱、分子 生物学和生化方法将被用来阐明3-羟基是如何 磷脂酰肌醇调节细胞粘附素-1的细胞内行为 生理作用被认为是粘附性的调节 通过与整合素受体的β2亚基相互作用 白细胞。整合素仲裁细胞和其 外部环境对许多细胞功能的调节，包括 胚胎发育、肿瘤细胞生长和转移、程序化细胞 死亡和白细胞归巢。细胞黏附调节的改变可以 也会导致一些疾病，其中包括类风湿性关节炎， 心血管疾病和癌症。生理学上的重要性 白细胞整合素被个体缺乏的发现所强调 β2亚单位患有一种严重的综合征，即白细胞粘连 虚弱，以无法清除病原体为特征，反复发作 感染，经常是早年死亡。该提案包括 三个特定目的：i)确定Pleckstrin同源性(PH) 细胞粘附素-1的结构域需要将细胞粘附素-1招募到细胞内 膜表面。Ii)确定细胞粘附素-I PH结构域是否结合 与特定的3-羟基磷脂酰肌醇结合足以募集细胞粘附素-1 到细胞膜上。Iii)确定细胞粘附素-1的结合是否 与质膜结合足以使其与整合素共定位 β2和/或与ADP核糖化因子。这个项目的中心是 了解去磷脂酰肌醇脂类第二信使如何调节 细胞粘附素-1在受体下的时空定位 控制力。

Two-photon laser scanning microscopy, fluorescence spectroscopy, molecular biology, and biochemical approaches will be used to elucidate how 3-OH phosphoinositide regulate the intracellular behavior of Cytohesin-1, whose physiological role has been suggested to be the regulation of adhesion through its interaction with the beta2 subunit of integrin receptors in leukocytes. Integrins arbitrate communications between the cell and its external environment in regulation of many cellular functions, including embryonic development, tumor cell growth and metastasis, programmed cell death, and leukocyte homing. Altered regulation of cellular adhesion can also contribute to a number of disorders, among them rheumatoid arthritis, cardiovascular disease, and cancer. The physiological importance of leukocyte integrins is underscored by the finding that individuals lacking the beta2 subunit suffer from a severe syndrome, leukocyte adhesion deficiency, characterized by an inability to clear pathogens, recurrent infections, and frequently, death at an early age. The proposal consists of three specific aims: i) To determine if the Pleckstrin Homology (PH) domain of Cytohesin-1 is required to recruit Cytohesin-1 to a cellular membrane surface. ii) To determine if binding of the Cytohesin-I PH domain to a specific 3-OH phosphoinositide is sufficient to recruit Cytohesin-1 to a cellular membrane. iii) To determine whether binding of Cytohesin-1 to the plasma membrane is sufficient for it to co-localize with integrin beta2 and/or with ADP Ribosylation Factor. This project is centered on understanding how DE-phosphoinositide lipid second messengers may regulate the spatial and temporal localization of Cytohesin-1 under receptor control.