So C W, Sham M H, Chew S L, Cheung N, So C K, Chung S K, Caldas C, Wiedemann L M, Chan L C
Department of Pathology, The University of Hong Kong, Hong Kong, Peoples' Republic of China.
Biochem J. 2000 Jun 1;348 Pt 2(Pt 2):447-58.
EEN, identified initially as a fusion partner to the mixed-lineage leukaemia gene in human leukaemia, and its related members, EEN-B1 and EEN-B2, have recently been shown to interact with two endocytic molecules, dynamin and synaptojanin, as well as with the huntingtin protein. In the present study, we show that the expression of the EEN gene-family members is differentially regulated. Multiple-spliced variants were identified for EEN-B2. In the brain, EEN-B1 and EEN-B2 mRNA are preferentially expressed in the cerebellar Purkinje and granule cells, dentate gyrus cells, hippocampal pyramidal neurons and cerebral granule cells. The expression patterns of EEN-B1 and EEN-B2 mRNA in the brain overlap with those of dynamin-I/III, synaptojanin-I and huntingtin, whereas the ubiquitous expression of EEN is consistent with that of dynamin-II. In testes, members of the EEN family are co-expressed with testis-type dynamin and huntingtin in Sertoli cells and germ cells respectively. Our results on the overlapping expression patterns are consistent with the proposed interaction of EEN family members with dynamin, synaptojanin and huntingtin protein in vivo. Although all three EEN family members bind to dynamin and synaptojanin, EEN-B1 has the highest affinity for binding, followed by EEN and EEN-B2. We also demonstrate that amphiphysin, a major synaptojanin-binding protein in brain, can compete with the EEN family for binding to synaptojanin and dynamin. We propose that recruitment of the EEN family by dynamin/synaptojanin to clathrin-coated pits can be regulated by amphiphysin.
EEN最初被鉴定为人类白血病中混合谱系白血病基因的融合伴侣，其相关成员EEN - B1和EEN - B2最近被证明可与两种内吞分子发动蛋白和突触素相互作用，还可与亨廷顿蛋白相互作用。在本研究中，我们表明EEN基因家族成员的表达受到差异调节。鉴定出了EEN - B2的多个剪接变体。在大脑中，EEN - B1和EEN - B2 mRNA优先在小脑浦肯野细胞和颗粒细胞、齿状回细胞、海马锥体神经元和大脑颗粒细胞中表达。EEN - B1和EEN - B2 mRNA在大脑中的表达模式与发动蛋白 - I/III、突触素 - I和亨廷顿蛋白的表达模式重叠，而EEN的普遍表达与发动蛋白 - II的表达一致。在睾丸中，EEN家族成员分别与睾丸型发动蛋白和亨廷顿蛋白在支持细胞和生殖细胞中共表达。我们关于重叠表达模式的结果与EEN家族成员在体内与发动蛋白、突触素和亨廷顿蛋白的拟议相互作用一致。尽管所有三个EEN家族成员都与发动蛋白和突触素结合，但EEN - B1具有最高的结合亲和力，其次是EEN和EEN - B2。我们还证明，脑内主要的突触素结合蛋白发动蛋白可与EEN家族竞争与突触素和发动蛋白的结合。我们提出，发动蛋白/突触素将EEN家族招募到网格蛋白包被小窝的过程可受发动蛋白调节。
