The precise balance of spindle orientations required for proper epidermal morphogenesis is regulated by mInscuteable expression and NuMA localization.

Cortical NuMA is essential for regulating spindle orientation and recruiting dynein/dynactin to the cell cortex. NuMA stability and spindle orientation activity require interactions with 4.1 family proteins in metaphase. In anaphase, loss of NuMA phosphorylation results in its cortical association in an LGN- and 4.1-independent manner.