Differential turnover of Nup188 controls its levels at centrosomes and role in centriole duplication

Abstract

NUP188 encodes a scaffold component of the nuclear pore complex (NPC) and has been implicated as a congenital heart disease gene through an ill-defined function at centrioles. Here, we explore the mechanisms that physically and functionally segregate Nup188 between the pericentriolar material (PCM) and NPCs throughout the cell cycle. Pulse-chase fluorescent labeling approaches indicate that Nup188 populates centrosomes with newly synthesized protein that does not exchange with NPCs even after mitotic NPC breakdown. In addition, the steady-state level of Nup188 at centrosomes is controlled by the sensitivity of the PCM pool, but not the NPC pool, to proteasomal degradation. Proximity-labeling and super-resolution microscopy supports that Nup188 interacts with components of PCM including Cep192 and the centriolar satellite component, PCM1. Consistent with this, Nup188 plays a role in centriole duplication at or upstream of Sas6 loading. Together, our data establish Nup188 as a functional component of PCM and potentially provides insight into the pathogenesis of congenital heart disease.