Function of FGF-2 associated protein (FAP) and its application for preventing reclosure after glaucoma filtration surgery.

通过酵母双杂交筛选研究FGF-2在细胞核中高分子量形式的功能，发现FAP是FGF相关蛋白。FAP基因序列与GenBank中报道的未鉴定的cDNA KIAA0092具有相似性。FAP含有500个氨基酸，具有与原肌球蛋白同源的基序，在n端形成盘绕状结构。该蛋白在c端还含有3个核定位信号。在HeLa细胞中，GFP-FAP融合蛋白以丝状结构为主，与微管共定位。为了确认MT与蛋白的结合和捆绑，用长春花碱处理表达GFP-FAP的HeLa细胞，以破坏MT网络。长春花碱在过表达GFP-FAP的细胞中不能破坏MT网络。在HeLa细胞中，每周表达的标记FAP融合蛋白似乎与MT共定位于有丝分裂细胞的纺锤体、纺锤极和中间体的MT。对各种FAP缺失突变体在细胞中的表达模式观察表明，c端有一半是MT结合域。酵母双杂交实验表明，FAP具有较强的自结合活性。这些结果表明FAP是至少部分与微管相关的自组装蛋白。这种蛋白质可能控制有丝分裂机制。胞内FAP与高分子量FGF-2在细胞核中的相互作用尚不清楚。

FAP has been found as FGF associated protein in the course of the study on the function of high molecular weight form of FGF-2 in nuclei by yeast two-hybrid screening. FAP gene shares sequence similarity with an uncharacterized cDNA reported in GenBank as KIAA0092. FAP contains 500 amino acids and has the motifs homologous to that of tropomyosin to form the coiled-coil structure at N-terminal side. The protein also contains 3 nuclear localizing signals at C-terminal side. GFP-FAP fusion protein over-expressed in HeLa cells was predominantly observed in filamentous structure and co-localized with microtubules (MT). To confirm MT binding and bundling of the protein, HeLa cells expressing GFP-FAP was treated with vinblastine to disassemble the MT network. Vinblastine was not able to disrupt MT networks in the cells over-expressing GFP-FAP. Weekly-expressed tagged FAP fusion proteins in HeLa cells appeared to be co-localized with MT as spindle, spindle pole and MT in midbody in the mitotic cells. Observations of expression pattern of various deletion mutants of FAP in the cells showed that a half of C-terminal is MT binding domain. Yeast two-hybrid assay showed that FAP also has a strong self-associating activity. These results indicate that FAP is self-assembling protein at least partly associating with microtubule. The protein may control the mitotic machinery. Intracellular interaction between FAP and high molecular weight form of FGF-2 in nuclei is still unclear.