Human Ninein (hNinein) is implicated in centrosomal microtubulenucleation and microtubule anchoring in interphase cells and may actas scaffold protein, but its interaction partner(s) is still poorlyunderstood. In this report, we show clearly that a spindle-associatedprotein Astrin could interact and co-localize with hNinein at thecentrosome during S and G2 phase of the cell cycle. In addition,hNinein truncated forms are able to affect Astrin localization to the centrosome, supporting the idea that Astrin is possibly localized at the centrosome via interaction with hNinein. Moreover, siRNA-mediatedknockdown of hNinein in HeLa cells causes Astrin to fail to localize atthe centrosome and block mitotic entry, whereas depletion of Astrin bysiRNA shows no detectable influence on the localization of hNinein to the centrosome. Remarkably, reduction in Astrin by siRNA-mediatedknockdown might result from uneven centrosome fragmentation andaneuploidy. Taken together, we propose a model where hNinein isrequired for Astrin targeting to the centrosome for the regulation of the dynamic movement of Astrin throughout the cell cycle and for maintaining centrosome/spindle pole integrity.
Date:
2006
Relation:
Molecular Biology of the Cell. 2006;17(Suppl. S):Abstract no L41.
