Johansen, KristenForer, ArthurYao, ChangfuGirton, JackJohansen, Jørgen2021-03-012021-03-012011-01Chromosome Research volume 19, pages345–365(2011)0967-3849https://doi.org/10.1007/s10577-011-9187-6http://hdl.handle.net/10315/38122This is a post-peer-review, pre-copyedit version of an article published in Chromosome Research. The final authenticated version is available online at: https://doi.org/10.1007/s10577-011-9187-6. More information on Springer Nature terms of reuse for archived author accepted manuscripts (AAMs) of subscription articles can be found at https://www.springer.com/gp/open-access/publication-policies/aam-terms-of-use.The idea of a spindle matrix has long been proposed in order to account for poorly understood features of mitosis. However, its molecular nature and structural composition have remained elusive. Here we propose that the spindle matrix may be constituted by mainly nuclear-derived proteins that reorganize during the cell cycle to form an elastic gel-like matrix. We discuss this hypothesis in the context of recent observations from phylogenetically diverse organisms that nuclear envelope and intranuclear proteins form a highly dynamic and malleable structure that contributes to mitotic spindle function. We suggest that the visco-elastic properties of such a matrix may constrain spindle length while at the same time facilitating microtubule growth and dynamics as well as chromosome movement. A corollary to this hypothesis is that a key determinant of spindle size may be the amount of nuclear proteins available to form the spindle matrix. Such a matrix could also serve as a spatial regulator of spindle assembly checkpoint proteins during open and semi-open mitosis.enAttribution-NoDerivatives 4.0 InternationalSpindle matrixMitosisNuclear envelopeNucleoporinsMicrotubulesNuclear reorganizationArticlehttps://www.springer.com/journal/10577https://link.springer.com/