Highly abundant component of the nuclear matrix where it may serve a non-mitotic structural role, occupies the majority if the nuclear volume. Required for maintenance and establishment of the mitotic spindle poles, functionning as a tether linking bulk microtubules of the spindle to centrosomes. May be involved in coordination of the alignment of the mitotic spindle to the cellular polarity axis, which is a prerequisite for asymmetric cell divisions.Yang C.H., J. Cell Biol. 116:1303-1317(1992).Compton D.A., J. Cell Biol. 116:1395-1408(1992).Maekawa T., J. Cell Sci. 105:589-600(1993).