NUMA, A NUCLEAR-PROTEIN INVOLVED IN MITOSIS AND NUCLEAR REFORMATION

NuMA, a nuclear protein that associates with the mitotic apparatus, was identified in 1980 as a high molecular weight component of the nuclear matrix with the unusual property of associating with the microtubules of the spindle apparatus during mitosis. Over the past two years, a burst of interest in this intriguing protein has led to the clear documentation of its cell cycle redistribution, determination of its primary sequence, elucidation of its cell cycle dependent targeting domains, as well as disruption of its function through antibody microinjection and expression of dominant-negative mutants. Together, these data support a central role for NuMA in both mitotic-spindle dynamics and the reformation of the daughter cell nuclei at the end of mitosis.