NDR1/2 kinases regulate cell polarization and cell motility through Cdc42 GTPase and Pard3 signaling in mammalian cells.

Controlling cell polarity and the directionality of cell motility is critical for effective cell migration during wound healing. NDR (nuclear dbf2-related) kinase pathways have roles in cell morphogenesis that are conserved from yeast to humans. Here, we reveal that knockdown of NDR1/2 kinases significantly alters cell size, shape, and the actin cytoskeleton, while reducing migration persistence and impairing cell polarization in wound healing assays. Mechanistically, we find that NDR1/2 kinases regulate the spatial and temporal dynamics of Cdc42 GTPase. Reduced NDR kinase levels increase Cdc42 GTPase activity and disrupt Pard3 subcellular location. NDR kinases phosphorylate Pard3 at Serine144, and overexpressing Pard3 can partially restore wound healing in NDR-depleted cells, an effect lost when Serine144 is mutated. Finally, we determine that NDR1 knockdown significantly impairs wound closure in human skin ex vivo wound healing assays, highlighting NDR kinase physiological importance. Collectively, this study demonstrates that NDR kinases modulate cell motility and polarization through the control of Pard3 and Cdc42 signaling in human fibroblasts.