Figure 6
From: Regulation of NDR1 activity by PLK1 ensures proper spindle orientation in mitosis
Working model accounting for PLK1-NDR1 signaling in mitotic spindle orientation control
Kinase regulators Mob1 and Mob2 competitively bind NDR1. Mob1-bound NDR1 is active with phosphorylation on Ser281 and Thr444, while Mob2-bound NDR1 is inactive. In normal mitosis, PLK1 phosphorylates NDR1 on three sites (Thr7, Thr183 and Thr407), switching NDR1 from Mob1-binding to Mob2-binding, hence prevents NDR1 from Mob1-elicited activation to ensure proper spindle orientation. In the case of reversal PLK1-elicited suppression of NDR1, the cortical localization of LGN-NuMA is liberated which leads to aberrant mitotic spindle orientation.
