Menin Associates with the Mitotic Spindle and is Important for Cell Division

Menin is the protein mutated in patients with multiple endocrine neoplasia
type 1 (MEN1) syndrome and their corresponding sporadic tumor
counterparts. Here, we have uncovered a novel function for menin in
promoting proper cell division. We show that menin localizes to the
mitotic spindle poles and the mitotic spindle during early mitosis and to
the intercellular bridge microtubules during cytokinesis in HeLa cells.
Menin depletion led to defects in spindle assembly and chromosome
congression during early mitosis, lagging chromosomes during anaphase,
defective cytokinesis, multinucleated interphase cells, and cell death.
Additionally, pharmacological inhibition of the menin-MLL1 interaction
also led to similar cell division defects. These results indicate that
menin and the menin-MLL1 interaction are important for proper cell
division. These results highlight a novel function for menin in cell
division and aid our understanding of how mutation and misregulation of
menin promotes tumorigenesis.