Dabbeekeh J T S, Faitar S L, Dufresne C P, Cowell J K
Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, NY 14263, USA.
Oncogene. 2007 Apr 26;26(19):2804-8. doi: 10.1038/sj.onc.1210081. Epub 2006 Nov 13.
The human EVI5 gene was originally isolated through its involvement with a constitutional chromosome translocation in a patient with stage 4S neuroblastoma. Recently, it has been shown that EVI5 is a centrosomal protein in interphase cells, which relocalizes to the midbody during late phases of mitosis. Disruption of its function leads to incomplete cell division and the formation of multinucleate cells. The EVI5 protein contains a TBC (TRE2/BUB/CDC16 homology) motif located in the N-terminal region. Proteins containing a TBC domain have been shown in some cases to act as GTPase-activating proteins (GAPs) and function through the interaction with Rab-like small G proteins. Despite the identification of over 50 TBC-containing proteins, and over 70 Rab-like proteins, only three combinations have been shown to have Rab/GAP activity to date. In this study, using linear ion trap mass spectroscopy, we have demonstrated that EVI5 exists in a protein complex with Rab11. Further, using a specific Rab-binding assay, we have shown that EVI5 preferentially interacts with the guanosine triphosphate-bound form of Rab11, and in a GAP activity assay, we have confirmed that EVI5 functions as a GAP for the Rab11 GTPase.
人类EVI5基因最初是通过参与一名4S期神经母细胞瘤患者的先天性染色体易位而分离出来的。最近研究表明，EVI5在间期细胞中是一种中心体蛋白，在有丝分裂后期重新定位于中间体。其功能的破坏会导致细胞分裂不完全并形成多核细胞。EVI5蛋白在N端区域含有一个TBC（TRE2/BUB/CDC16同源）基序。在某些情况下，含有TBC结构域的蛋白质已被证明可作为GTP酶激活蛋白（GAP），并通过与Rab样小G蛋白相互作用发挥功能。尽管已鉴定出50多种含TBC的蛋白质和70多种Rab样蛋白质，但迄今为止只有三种组合显示出具有Rab/GAP活性。在本研究中，我们使用线性离子阱质谱法证明EVI5与Rab11存在于一个蛋白质复合物中。此外，通过特定的Rab结合试验，我们表明EVI5优先与鸟苷三磷酸结合形式的Rab11相互作用，并且在GAP活性试验中，我们证实EVI5作为Rab11 GTP酶的GAP发挥作用。
