Popov A V, Pozniakovsky A, Arnal I, Antony C, Ashford A J, Kinoshita K, Tournebize R, Hyman A A, Karsenti E
Cell Biology Program, EMBL, Meyerhofstrasse 1, Heidelberg 69117, Germany.
EMBO J. 2001 Feb 1;20(3):397-410. doi: 10.1093/emboj/20.3.397.
XMAP215 belongs to a family of proteins involved in the regulation of microtubule dynamics. In this study we analyze the function of different parts of XMAP215 in vivo and in Xenopus egg extracts. XMAP215 has been divided into three fragments, FrN, FrM and FrC (for N-terminal, middle and C-terminal, respectively). FrN co-localizes with microtubules in egg extracts but not in cells, FrC co- localizes with microtubules and centrosomes both in egg extracts and in cells, while FrM does not co- localize with either centrosomes or microtubules. In Xenopus egg extracts, FrN stimulates microtubule growth at plus-ends by inhibiting catastrophes, while FrM has no effect, and FrC suppresses microtubule growth by promoting catastrophes. Our results suggest that XMAP215 is targeted to centrosomes and microtubules mainly through its C-terminal domain, while the evolutionarily conserved N-terminal domain contains its microtubule-stabilizing activity.
XMAP215属于参与微管动力学调节的蛋白质家族。在本研究中,我们分析了XMAP215不同部分在体内和非洲爪蟾卵提取物中的功能。XMAP215已被分为三个片段,即FrN、FrM和FrC(分别代表N端、中间和C端)。FrN在卵提取物中与微管共定位,但在细胞中不共定位;FrC在卵提取物和细胞中均与微管和中心体共定位,而FrM与中心体或微管均不共定位。在非洲爪蟾卵提取物中,FrN通过抑制微管末端的灾变来刺激微管生长,而FrM无此作用,FrC则通过促进灾变来抑制微管生长。我们的结果表明,XMAP215主要通过其C端结构域靶向中心体和微管,而进化上保守的N端结构域则具有微管稳定活性。