Abstract
Cells entering mitosis become rounded, lose attachment to the substrate, and increase their cortical rigidity. Pivotal to these events is the dismantling of focal adhesions (FAs). How mitotic reshaping is linked to commitment to divide is unclear. Here, we show that DEPDC1B, a protein that accumulates in G2, coordinates de-adhesion events and cell-cycle progression at mitosis. DEPDC1B functions as an inhibitor of a RhoA-based signaling complex, which assembles on the FA-associated protein tyrosine phosphatase, receptor type, F (PTPRF) and mediates the integrity of FAs. By competing with RhoA for the interaction with PTPRF, DEPDC1B promotes the dismantling of FAs, which is necessary for the morphological changes preceding mitosis. The circuitry is relevant in whole organisms, as shown by the control exerted by the DEPDC1B/RhoA/PTPRF axis on mitotic dynamics during zebrafish development. Our results uncover an adhesion-dependent signaling mechanism that coordinates adhesion events with the control of cell-cycle progression.