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

在利用酵母双杂交技术研究细胞核内FGF-2高分子形式功能的过程中，发现FAP是FGF相关蛋白。FAP基因与GenBank中报道的KIAA0092的cDNA序列相似。FAP由500个氨基酸组成，具有与原肌球蛋白同源的基序，在N端形成卷曲螺旋结构。该蛋白在C-末端还含有3个核定位信号。在HeLa细胞中过表达的GFP-FAP融合蛋白主要以丝状结构存在，并与微管（MT）共定位。为了证实MT结合和蛋白质的捆绑，用长春碱处理表达GFP-FAP的HeLa细胞以分解MT网络。长春碱不能破坏过表达GFP-FAP的细胞中的MT网络。在HeLa细胞中表达的标记FAP融合蛋白在有丝分裂期与MT共定位于纺锤体、纺锤极和中间体。观察FAP各种缺失突变体在细胞中的表达模式，发现其C端有一半是MT结合结构域。酵母双杂交实验表明FAP也具有较强的自缔合活性。这些结果表明，FAP是一种自组装蛋白，至少部分与微管结合。蛋白质可以控制有丝分裂机制。FAP和高分子量形式的FGF-2在细胞核中的细胞内相互作用仍不清楚。

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.