Lu Lei, Hong Wanjin
Membrane Biology Laboratory, Institute of Molecular and Cell Biology, Singapore 117609, Singapore.
Mol Biol Cell. 2003 Sep;14(9):3767-81. doi: 10.1091/mbc.e03-01-0864. Epub 2003 May 18.
A cellular role and the mechanism of action for small GTPase Arl1 have been defined. Arl1-GTP interacts with the GRIP domains of Golgin-97 and Golgin-245, a process dependent on conserved residues of the GRIP domains that are important for Golgi targeting. The switch II region of Arl1 confers the specificity of this interaction. Arl1-GTP mediates Golgi recruitment of Golgin-97 in a switch II-dependent manner, whereas tethering Arl1-GTP onto endosomes can mediate endosomal targeting of Golgin-97. Golgin-97 and Golgin-245 are dissociated from the Golgi when Arl1 is knocked-down by its siRNA. Arl1-GTP thus functions to recruit Golgin-97 and Golgin-245 onto the Golgi via interacting with their GRIP domains.
小GTP酶Arl1的细胞作用及其作用机制已被明确。Arl1-GTP与高尔基体蛋白97（Golgin-97）和高尔基体蛋白245（Golgin-245）的GRIP结构域相互作用，这一过程依赖于GRIP结构域的保守残基，这些残基对高尔基体靶向至关重要。Arl1的开关II区域赋予了这种相互作用的特异性。Arl1-GTP以开关II依赖的方式介导Golgin-97向高尔基体的募集，而将Arl1-GTP栓系在内体上可介导Golgin-97向内体的靶向。当Arl1被其小干扰RNA（siRNA）敲低时，Golgin-97和Golgin-245会从高尔基体上解离。因此，Arl1-GTP通过与Golgin-97和Golgin-245的GRIP结构域相互作用，将它们募集到高尔基体上发挥作用。
