Non Fiber Cell Functions for the Beaded Filament Proteins

摘要 珠状纤维(BF)是一种结构上和生化上的丝状细胞骨架结构，发现于 晶状体纤维细胞。在40年里，无论是BF还是组装BF所需的两种蛋白质(BF蛋白质 CP49和微丝蛋白)，已经在分化的晶状体纤维细胞以外的细胞中被证实。在预赛中 数据显示，BF蛋白在晶状体上皮细胞中表达，但也在活检的人类亚群中表达 癌症。此外，BF蛋白在晶状体上皮细胞中的表达不是丝状结构，而是 大的蠕虫状结构，仅在5周龄后才表现出来。作为靠近弓部区域的单元格 分化被触发，结构就消失了。这些数据：1)是(据我们所知)第一次报告 BF蛋白在纤维细胞外和晶状体外的表达表明晶状体上皮细胞 可能组装了一个新的细胞器/包涵体，以及3)发育开关仍在晶状体中翻转 5周龄的上皮细胞。因此，这些观察结果表明，BF具有以前未知的功能 晶状体和非晶状体组织中的蛋白质，以及正常和病理生物学中的蛋白质。我们不知道 这个函数是什么，并调用这个R21来开始建立这个/这些函数的过程(S)。 在过去的25年里，我们的实验室一直致力于珠状长丝和中长丝的研究。正在做 因此，我们积累了BF/IF工具、资源和晶状体生物学方面的经验， 独特的地理位置使我们在揭示这种“非规范的”BF蛋白功能方面取得了进展。因为 这些工具的可用性(CP49基因敲除、细丝蛋白基因敲除和波形蛋白基因敲除动物，一系列 抗BF蛋白、波形蛋白和其他几种晶状体蛋白、cDNA结构等的抗体)，以及由于 由于稀有人类肿瘤材料的有限，我们将最初的努力集中在晶状体上。 当然，对于一个新颖的结构，人们可以提出大量的问题，但 R21的限制限制了调查的范围。出于这个原因，我们提出了三个层面的问题， 分子、细胞和组织水平，以撒下尽可能广泛的网。所提出的问题由我们的 有关晶状体、中间纤维、珠状纤维的知识，以及细胞细胞器和 包裹体。 就像我们之前的工作从纤维细胞特有的细胞骨架结构(BF)开始并成长为 对中间丝结构的总体攻击，我们希望这些研究将超越透镜 上皮学--特定于更广泛的细胞生物学领域。

Abstract Beaded Filaments (BFs) are a structurally and biochemically filamentous cytoskeletal structure found in lens fiber cells. In 40 years, neither the BF nor the two proteins required for assembly of the BF (BF Proteins CP49 and filensin), have been demonstrated in cells other than differentiated lens fiber cells. In Preliminary Data, we show that BF proteins are expressed in lens epithelium, but also in a subset of biopsied human cancers. Moreover, BF protein expression in lens epithelium is not in a filamentous structure, but instead in a large vermiform structure, which is only expressed after 5 weeks of age. As cells near the bow region where differentiation is triggered, the structure disappears. These data: 1) are the first to report (to our knowledge) the expression of BF proteins outside of the fiber cell, and outside of the lens 2) suggest that the lens epithelium may assemble a novel organelle/inclusion, and 3) that developmental switches are still being flipped in the lens epithelium at 5 weeks of age. Thus, these observations suggest a previously unknown function for the BF Proteins, both in the lens, and in non-lens tissue, and in both normal and pathologic biology. We have no idea what this function is, and invoke this R21 to begin the process of establishing this/these function(s). Our lab has worked on Beaded Filaments and Intermediate Filaments for the past 25 years. In doing so we have accumulated a combination of BF/IF tools, resources, and experience in lens biology, which uniquely situates us to make progress in revealing this "non-canonical" BF protein function. Because of the availability of these tools (CP49 knockout, filensin knockout, and vimentin-knockout animals, a range of antibodies to BF proteins, vimentin, and several other lens proteins, cDNA constructs, etc) and because of the limited availability of rare human tumor material, we focus these initial efforts on lens. There are, of course, a vast number of questions that can be asked about a novel structure, but the R21 limitations constrain the scope of inquiry. For that reason we are proposing questions at three levels, the molecular, cellular and tissue levels, to cast the widest net possible. The questions asked are guided by our knowledge of lens, intermediate filaments, beaded filaments, and the literature on cellular organelles and inclusions. Just as our previous work started with a fiber cell-specific cytoskeletal structure (the BF) and grew into a general attack on the structure of Intermediate Filaments, we hope that these studies will transcend from lens epithelial-specific to the broader field of cell biology.