Survivin Modulates Microtubule Dynamics and Nucleation throughout the Cell Cycle

Abstract

Survivin is a member of the chromosomal passenger complex implicated in kinetochore attachment, bipolar spindle formation, and cytokinesis. However, the mechanism by which survivin modulates these processes is unknown. Here, we show by time-lapse imaging of cells expressing either green fluorescent protein (GFP)-␣-tubulin or the microtubule plus-end binding protein GFP-EB1 that depletion of survivin by small interfering RNAs (siRNAs) increased both the number of microtubules nucleated by centrosomes and the incidence of microtubule catastrophe, the transition from microtubule growth to shrinking. In contrast, survivin overexpression reduced centrosomal microtubule nucleation and suppressed both microtubule dynamics in mitotic spindles and bidirectional growth of microtubules in midbodies during cytokinesis. siRNA depletion or pharmacologic inhibition of another chromosomal passenger protein Aurora B, had no effect on microtubule dynamics or nucleation in interphase or mitotic cells even though mitosis was impaired. We propose a model in which survivin modulates several mitotic events, including spindle and interphase microtubule organization, the spindle assembly checkpoint and cytokinesis through its ability to modulate microtubule nucleation and dynamics. This pathway may affect the microtubule-dependent generation of aneuploidy and defects in cell polarity in cancer cells, where survivin is commonly up-regulated.

Latent membrane protein 1 suppresses RASSF1A expression, disrupts microtubule structures and induces chromosomal aberrations in human epithelial cells

“…We previously revealed that overexpression of survivin could dramatically reduce microtubule nucleation and dynamics (Rosa et al, 2006). Interestingly, survivin is also a downstream target of LMP1 expression and NFkB activation.…”

“…They were maintained in DMEM and DMEM: HAMF12 medium in a 3:1 ratio, respectively. The RPE hTert were obtained from Clontech (CA, USA); and has been used in previous studies of microtubule function (Rosa et al, 2006).…”

“…Retinal pigment epithelial (RPE) cells, which are commonly used in the study of microtubule dynamics was used in this part of study. The RPE cells used were stably transfected with pEGFP-EB1 expression plasmid (Rosa et al, 2006). Microtubules' plus ends are binding sites for EB1 protein.…”

“…Genetic suppressor of NF-kB (pUSE-IkBa S32/S36) and the activator of NF-kB (pRc-bactin-IKKa) had been described previously (Jin et al, 1999). The plasmid for imaging microtubule structure (pEGFP-a-tubulin) and the plasmid for imaging dynamics of microtubule plus-ends binding protein in live cells (pEGFP-EB1) had been described (Rosa et al, 2006). Transfection marker (pDsRed) was obtained from Clonetech laboratories Inc., CA, USA.…”

Cyclin G2 is a centrosome-associated nucleocytoplasmic shuttling protein that influences microtubule stability and induces a p53-dependent cell cycle arrest

“…Interestingly, APC associates with PP2A B' subunits [91], though the importance of this association for its cytoskeletal functions is unknown. Another protein linked to cellular stress responses and regulation of cell division, survivin, localizes to multiple sites on the mitotic apparatus, including centrosomes, microtubules of the metaphase and central spindle, kinetochores, and midbodies [92,93]. Survivin has recently been found to modulate microtubule dynamics and nucleation throughout the cell cycle [92].…”