Cheng Tai-Shan, Chang Li-Kwan, Howng Shen-Long, Lu Pei-Jung, Lee Chu-I, Hong Yi-Ren
Graduate Institute of Biochemistry, Kaohsiung, Taiwan, ROC.
Life Sci. 2006 Feb 2;78(10):1114-20. doi: 10.1016/j.lfs.2005.06.021. Epub 2005 Sep 9.
A centrosomal-associated protein, ninein is a microtubules minus end capping, centrosome position, and anchoring protein, but the underlying structure and physiological functions are still unknown. To identify the molecules that regulate the function of human ninein in centrosome, we performed yeast two-hybrid screen and isolated the SUMO-conjugating E2 enzyme, Ubc9, and SUMOylation enhancing enzymes, including PIAS1 and PIASxalpha, as binding partners of hNinein. These interactions as well as the interaction between hNinein and SUMO-1 are also confirmed by a glutathione S-transferase (GST) pull-down experiment. Furthermore, the C-terminal region of hNinein can be SUMOylated in vitro and in HeLa cells transfected with a plasmid expressing GFP-hNinein. Our findings firstly place SUMOylation target on the centrosome structure protein, hNinein, which results in the switch localization from centrosome to nucleus, suggesting the importance of the SUMOylation of hNinein and probably other centrosomal proteins may also be involved in the centrosome activity.
九蛋白是一种与中心体相关的蛋白质，它是一种微管负端封端、中心体定位和锚定蛋白，但其潜在结构和生理功能仍不清楚。为了鉴定调节人类九蛋白在中心体中功能的分子，我们进行了酵母双杂交筛选，并分离出了SUMO缀合E2酶Ubc9以及包括PIAS1和PIASxα在内的SUMO化增强酶，作为hNinein的结合伴侣。谷胱甘肽S-转移酶（GST）下拉实验也证实了这些相互作用以及hNinein与SUMO-1之间的相互作用。此外，hNinein的C末端区域在体外以及在用表达GFP-hNinein的质粒转染的HeLa细胞中均可被SUMO化。我们的研究结果首次将SUMO化靶点定位在中心体结构蛋白hNinein上，这导致其定位从中心体切换到细胞核，表明hNinein的SUMO化很重要，并且可能其他中心体蛋白也可能参与中心体活性。
