Transparency represents the functional phenotype of eye lens. A number of defined steps including quiescence, proliferation, migration and cell differentiation culminates in cell elongation and organelle degradation, allowing the light to reach the retina. HOPS/TMUB1 is a nucleo-cytoplasmic shuttling protein, highly expressed both in vivo and in vitro proliferating systems, bearing an ubiquitin-like domain. The present study shows HOPS expression during the phases of lens cell proliferation and fiber differentiation, and its localization in lens compartments. In lens, HOPS localizes mainly in the nucleus of central epithelial cells. During mitosis HOPS/TMUB1 shuttles to the cytoplasm and returns in the nucleus at the end of mitosis. The differentiating cells share distinct HOPS/TMUB1 localization in transitional zone depending on the differentiation phases. HOPS/TMUB1 is observed in lens cortex and nucleus. Here, it is attached to fibers, having a structural function with crystallin proteins, probably acting in the ubiquitin-proteasome system.

中文翻译：

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HOPS/TMUB1 在小鼠晶状体中的功能表达和定位。

透明度代表眼睛晶状体的功能表型。许多明确的步骤包括静止、增殖、迁移和细胞分化，最终导致细胞伸长和细胞器降解，使光线到达视网膜。HOPS/TMUB1 是一种核质穿梭蛋白，在体内和体外增殖系统中均高度表达，具有泛素样结构域。本研究显示了晶状体细胞增殖和纤维分化阶段的 HOPS 表达及其在晶状体隔室中的定位。在晶状体中，HOPS 主要位于中央上皮细胞的细胞核中。在有丝分裂期间，HOPS/TMUB1 穿梭于细胞质并在有丝分裂结束时返回细胞核。根据分化阶段，分化细胞在过渡区共享不同的 HOPS/TMUB1 定位。在晶状体皮质和细胞核中观察到 HOPS/TMUB1。在这里，它附着在纤维上，具有晶体蛋白的结构功能，可能在泛素-蛋白酶体系统中起作用。