Endosomal localization of the autoantigen EEA1 is mediated by a zinc-binding FYVE finger
Endosomal localization of the autoantigen EEA1 is mediated by a zinc-binding FYVE finger
复制标题
DOI：
10.1074/jbc.271.39.24048
复制
发表时间：
1996-09-27
影响因子：
4.8
通讯作者：
DArrigo, A
中科院分区：
文献类型：
--
作者：
Stenmark, H;Aasland, R;DArrigo, A
EEA1是一种与亚急性皮肤系统性红斑狼疮相关的162 kda自身抗原，是一种定位于早期内体和细胞质的卷曲卷曲蛋白。在C端，该蛋白含有一个富含半胱氨酸的基元，该基元与Vps27、Fab1和Vac1（酵母蛋白参与膜运输）共享（Mu， F. T., Callaghan， J. M., Steele-Mortimer， O., Stenmark， H., Parton， R. G., Campbell， P. L., McCluskey， J., Yeo， J. P., Tock， E. P., and Toh， B. H., 1995）。化学，270,13503 -13511)。在这里，我们表明该基序构成了一个真正的锌结合域，我们称之为FYVE指（基于包含该基序的四个蛋白质的首字母）。基于图谱的数据库搜索在11种不同的蛋白质中发现了FYVE手指。发现含有EEA1 C端的FYVE指结合了2 mol当量的Zn2+。FYVE基序中保守组氨酸和半胱氨酸残基的突变独立地将锌结合降低到1 mol当量。转染HEp2细胞的共聚焦免疫荧光显微镜显示，EEA1的c端部分（残基1277-1411）与早期内体GTPase Rab5的GTPase缺陷突变体广泛共定位，而FYVE指的缺失或干扰锌结合的突变导致细胞质定位。这些结果提示FYVE指在EEA1特异定位到核内体中。
EEA1, a 162-kDa autoantigen associated with subacute cutaneous systemic lupus erythematosus, is a coiled-coil protein localized to early endosomes and cytosol. At its C terminus, the protein contains a cysteine rich motif, which is shared with Vps27, Fab1, and Vac1, yeast proteins implicated in membrane traffic (Mu, F. T., Callaghan, J. M., Steele-Mortimer, O., Stenmark, H., Parton, R. G., Campbell, P. L., McCluskey, J., Yeo, J. P., Tock, E. P., and Toh, B. H. (1995) J. Biol. Chem. 270, 13503-13511). Here we show that this motif constitutes a genuine zinc binding domain, which we term the FYVE finger (based on the first letters of four proteins containing this motif). Profile based data base searches identified the FYVE finger in 11 distinct proteins. The FYVE finger containing C terminus of EEA1 was found to bind 2 mol equivalents of Zn2+. Mutations of conserved histidine and cysteine residues in the FYVE motif independently reduced zinc binding to 1 mol equivalent. Confocal immunofluorescence microscopy of transfected HEp2 cells revealed that the C-terminal part (residues 1277-1411) of EEA1 colocalizes extensively with a GTPase deficient mutant of the early endosomal GTPase Rab5, while deletion of the FYVE finger or mutations that interfere with zinc binding cause a cytosolic localization. These results implicate the FYVE finger in the specific localization of EEA1 to endosomes.