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Excess TPX2 Interferes with Microtubule Disassembly and Nuclei Reformation at Mitotic Exit.

Published version
Peer-reviewed

Type

Article

Change log

Authors

Naso, Francesco D 
Sterbini, Valentina 
Crecca, Elena 
Asteriti, Italia A 
Russo, Alessandra D 

Abstract

The microtubule-associated protein TPX2 is a key mitotic regulator that contributes through distinct pathways to spindle assembly. A well-characterised function of TPX2 is the activation, stabilisation and spindle localisation of the Aurora-A kinase. High levels of TPX2 are reported in tumours and the effects of its overexpression have been investigated in cancer cell lines, while little is known in non-transformed cells. Here we studied TPX2 overexpression in hTERT RPE-1 cells, using either the full length TPX2 or a truncated form unable to bind Aurora-A, to identify effects that are dependent-or independent-on its interaction with the kinase. We observe significant defects in mitotic spindle assembly and progression through mitosis that are more severe when overexpressed TPX2 is able to interact with Aurora-A. Furthermore, we describe a peculiar, and Aurora-A-interaction-independent, phenotype in telophase cells, with aberrantly stable microtubules interfering with nuclear reconstitution and the assembly of a continuous lamin B1 network, resulting in daughter cells displaying doughnut-shaped nuclei. Our results using non-transformed cells thus reveal a previously uncharacterised consequence of abnormally high TPX2 levels on the correct microtubule cytoskeleton remodelling and G1 nuclei reformation, at the mitosis-to-interphase transition.

Description

Keywords

TPX2, mitosis, nuclear envelope, spindle, Aurora Kinase A, Cell Cycle Proteins, Cell Line, Cell Nucleus, Chromatin, Cytoskeleton, Golgi Apparatus, Humans, Lamin Type B, Metaphase, Microtubule-Associated Proteins, Microtubules, Mitosis, Protein Binding, Telophase

Journal Title

Cells

Conference Name

Journal ISSN

2073-4409
2073-4409

Volume Title

9

Publisher

MDPI AG
Sponsorship
Royal Society (IES/R3/170195)
Biotechnology and Biological Sciences Research Council (BB/R004137/1)