Glycogen synthase kinase 3β interacts with and phosphorylates the spindle-associated protein astrin
Glycogen synthase kinase 3β interacts with and phosphorylates the spindle-associated protein astrin
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DOI：
10.1074/jbc.m706794200
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发表时间：
2008-01-25
影响因子：
4.8
通讯作者：
Hong, Yi-Ren
中科院分区：
文献类型：
--
作者：
Cheng, Tai-Shan;Hsiao, Yun-Ling;Hong, Yi-Ren
新出现的证据表明，糖原合成酶激酶3 β（GSK 3 β）参与有丝分裂，抑制GSK 3 β激酶活性会导致纺锤体微管长度和染色体排列缺陷。然而，GSK 3 β参与纺锤体微管组装和精确染色体分离的目的仍然不清楚。在这里，我们报道了GSK 3 β在体外和体内与纺锤体相关蛋白Astrin相互作用。此外，Astrin作为GSK 3 β的底物，在Thr- 111、Thr- 937（（S/ T）P基序）和Ser- 974/ Thr-978（（S/ T）XXX（S/T）- p基序; p是可磷酸化残基）处磷酸化。GSK 3 β的抑制损害了Astrin的纺锤体和动粒积累以及有丝分裂时的纺锤体形成，表明Astrin与纺锤体微管和动粒的结合可能依赖于GSK 3 β的磷酸化。相反，小干扰RNA对Astrin的消耗对GSK 3 β的定位没有可检测的影响。有趣的是，体外试验表明，Astrin增强GSK 3 β介导的其他底物的磷酸化。此外，我们发现，Astrin和GSK 3 β的共表达差异性地增加了GSK 3 β介导的未引发位点上的Tau磷酸化。总的来说，这些数据表明GSK 3 β与纺锤体相关蛋白Astrin相互作用并使其磷酸化，导致Astrin靶向纺锤体微管和动粒。反过来，GSK 3 β-Astrin复合物可能促进进一步的生理和病理磷酸化。
Emerging evidence shows that glycogen synthase kinase 3 beta (GSK3 beta) is involved in mitotic division and that inhibiting of GSK3 beta kinase activity causes defects in spindle microtubule length and chromosome alignment. However, the purpose of GSK3 beta involvement in spindle microtubule assembly and accurate chromosome segregation remains obscure. Here, we report that GSK3 beta interacts with the spindle- associated protein Astrin both in vitro and in vivo. Additionally, Astrin acts as a substrate for GSK3 beta and is phosphorylated at Thr- 111, Thr- 937 ((S/ T) P motif) and Ser- 974/ Thr-978 ((S/ T) XXX(S/T)- p motif; p is a phosphorylatable residue). Inhibition of GSK3 beta impairs spindle and kinetochore accumulation of Astrin and spindle formation at mitosis, suggesting that Astrin association with the spindle microtubule and kinetochore may be dependent on phosphorylation by GSK3 beta. Conversely, depletion of Astrin by small interfering RNA has no detectable influence on the localization of GSK3 beta. Interestingly, in vitro assays demonstrated that Astrin enhances GSK3 beta- mediated phosphorylation of other substrates. Moreover, we showed that coexpression of Astrin and GSK3 beta differentially increases GSK3 beta- mediated Tau phosphorylation on an unprimed site. Collectively, these data indicate that GSK3 beta interacts with and phosphorylates the spindle- associated protein Astrin, resulting in targeting Astrin to the spindle microtubules and kinetochores. In turn, the GSK3 beta-Astrin complex may facilitate further physiological and pathological phosphorylation.