Golgi partitioning controls mitotic entry through Aurora-A kinase

At the onset of mitosis, the Golgi complex undergoes a multi-step fragmentation process that is required for its correct partitioning into the daughter cells. Inhibition of this Golgi fragmentation results in cell-cycle arrest at the G2 stage, thus suggesting that correct inheritance of the Golgi complex is monitored by a 'Golgi mitotic checkpoint'. However, the molecular basis of this G2 block is not known. Here, we show that the G2-specific Golgi fragmentation stage is concomitant with centrosome recruitment and activation of the mitotic kinase Aurora-A, an essential regulator for entry into mitosis. We show that a block of Golgi partitioning impairs centrosome recruitment and activation of Aurora-A, which results in the G2 block of cell-cycle progression. Overexpression of Aurora-A overrides this cell-cycle block, indicating that Aurora-A is a major effector of the Golgi checkpoint. Our findings provide the basis for further understanding of the signaling pathways that coordinate organelle inheritance and cell duplication.