The Golgi complex is a regulatory hub for homologous recombination-mediated DNA repair

The Golgi complex has long been recognised as an important homeostasis hub, where a multitude of signalling pathways and essential cellular processes intersect. Yet its communication with the cell nucleus remains largely unexplored. To this end, we have analysed genome-scale localisation data of the Human Protein Atlas which revealed an unexpected high number of Golgi and nuclear dual-localisation proteins and several pathways including surprising DNA repair. Amongst these proteins we found RAD51C, a regulatory Homologous Recombination (HR) repair protein, that localises to the Golgi and in response to double-strand DNA breaks, the Golgi protein population of RAD51C redistributes to form DNA repair foci. Depletion of the Golgin Giantin induces the redistribution of the RAD51C Golgi pool to form nuclear foci, independent of DNA damage induction. Concurrent with a significant increase in genomic instability and inhibition of HR signalling regulators. Altogether, we present evidence for a novel pathway where the Golgi is a central regulatory hub for HR-mediated DNA repair and potentially other repair pathways.