Cheung Ngai, So Chi Wai, Yam Judy W P, So C K C, Poon Randy Y C, Jin Dong-Yan, Chan Li Chong
Department of Pathology, University of Hong Kong, Pokfulam, Hong Kong, People's Republic of China.
Biochem J. 2004 Oct 1;383(Pt 1):27-35. doi: 10.1042/BJ20040041.
EEN (extra eleven nineteen), also known as EA2 (endophilin A2), a fusion partner of the MLL (mixed-lineage leukaemia) gene in human acute leukaemia, is a member of the endophilin A family, involved in the formation of endocytic vesicles. We present evidence to show that EEN/EA2 is localized predominantly in nuclei of various cell lines of haemopoietic, fibroblast and epithelial origin, in contrast with its reported cytoplasmic localization in neurons and osteoclasts, and that EEN/EA2 exhibits nucleocytoplasmic shuttling. During the cell cycle, EEN/EA2 shows dynamic localization: it is perichromosomal in prometaphase, co-localizes with the bipolar spindle in metaphase and anaphase and redistributes to the midzone and midbody in telophase. This pattern of distribution coincides with changes in protein levels of EEN/EA2, with the highest levels being observed in G2/M-phase. Our results suggest that distinct subcellular localization of the endophilin A family members probably underpins their diverse cellular functions and indicates a role for EEN/EA2 in the cell cycle.
EEN（额外的11号染色体上的19号基因），也被称为EA2（内吞蛋白A2），是人类急性白血病中混合谱系白血病（MLL）基因的融合伴侣，属于内吞蛋白A家族成员，参与内吞小泡的形成。我们提供的证据表明，EEN/EA2主要定位于造血、成纤维细胞和上皮来源的各种细胞系的细胞核中，这与报道的其在神经元和破骨细胞中的细胞质定位不同，并且EEN/EA2表现出核质穿梭。在细胞周期中，EEN/EA2呈现动态定位：在有丝分裂前期位于染色体周围，在中期和后期与双极纺锤体共定位，并在末期重新分布到中间区和中间体。这种分布模式与EEN/EA2蛋白水平的变化一致，在G2/M期观察到最高水平。我们的结果表明，内吞蛋白A家族成员不同的亚细胞定位可能是其多种细胞功能的基础，并表明EEN/EA2在细胞周期中发挥作用。
