MOLECULAR BASIS OF MYOCILIN FUNCTION IN THE HUMAN EYE

已经确定了参与开角型青光眼发病机制的分子组分。 在某些人中，导致高眼压和开角型青光眼的突变位于青光眼基因中 位于1号染色体基因座GLC 1A上，该基因座编码一种名为myocilin的蛋白质。不幸的是， myocilin未知。肌球蛋白由几种眼组织表达，包括小梁网、角膜内皮细胞和角膜内皮细胞。 开角型青光眼高眼压的可能病理部位。在亚细胞水平上， 局限于小梁网细胞的囊泡室，涉及囊泡运输和/或 分泌物作为青光眼的影响途径。本项目初期供资期的进展情况 其特征在于肌球蛋白是一种胞质蛋白，与一类细胞内囊泡相关， 小梁网细胞称为“外来体”。因此，myocilin不是以传统方式分泌，而是 离开小梁网细胞并进入与外来体相关的细胞外室。 本研究的总体目标是确定肌钙蛋白在小梁网中的功能 细胞以及myocilin突变如何影响其细胞外外观。我们假设， myocilin干扰外泌体释放递送。为了验证这一假设，我们设计了两个 互补的具体目标：（i）确定肌球蛋白与细胞内 （ii）确定肌球蛋白突变体对小梁网细胞中的细胞膜（外来体）的影响， 从人小梁网细胞释放外泌体。

A molecular component involved in the pathogenesis of open-angle glaucoma has been identified. Mutations causing ocular hypertension and open-angle glaucoma in some are located to a glaucoma gene on a chromosome 1 locus, GLC1A, that codes for a protein called myocilin. Unfortunately the function of myocilin is unknown. Myocilin is expressed by several eye tissues, including the trabecular meshwork, the likely site of pathology for ocular hypertension in open-angle glaucoma. On a subcellular level, myocilin localizes to the vesicular compartment of trabecular meshwork cells, implicating vesicular traffic and/or secretion as affected pathways in glaucoma. Progress in the initial funding period of this project characterized myocilin as a cytosolic protein that associates with a class of intracellular vesicles in trabecular meshwork cells called "exosomes". Thus, myocilin is not secreted in a traditional manner, but exits trabecular meshwork cells and enters the extracellular compartment associated with exosomes. The overall goal of the present proposal is to determine the function of myocilin in trabecular meshwork cells and how mutations in myocilin impact its extracellular appearance. We hypothesize that mutations in myocilin interfere with delivery of exosomes for release. To test this hypothesis, we have designed two complimentary specific aims: (i) Identify the mechanism by which myocilin associates with intracellular membranes (exosomes) in trabecular meshwork cells and (ii) Determine effects of myocilin mutants on release of exosomes from human trabecular meshwork cells .