Nup133 Is Required for Proper Nuclear Pore Basket Assembly and Dynamics in Embryonic Stem Cells

Abstract

Summary: Nup133 belongs to the Y-complex, a key component of the nuclear pore complex (NPC) scaffold. Studies on a null mutation in mice previously revealed that Nup133 is essential for embryonic development but not for mouse embryonic stem cell (mESC) proliferation. Using single-pore detection and average NE-fluorescence intensity, we find that Nup133 is dispensable for interphase and postmitotic NPC scaffold assembly in pluripotent mESCs. However, loss of Nup133 specifically perturbs the formation of the nuclear basket as manifested by the absence of Tpr in about half of the NPCs combined with altered dynamics of Nup153. We further demonstrate that its central domain mediates Nup133’s role in assembling Tpr and Nup153 into a properly configured nuclear basket. Our findings thus revisit the role of the Y-complex in pore biogenesis and provide insights into the interplay between NPC scaffold architecture, nuclear basket assembly, and the generation of heterogeneity among NPCs. : Souquet et al. report that Nup133, a structural component of the nuclear pore complex (NPC), is dispensable for NPC scaffold formation during post-mitotic and interphase pore assembly in embryonic stem cells. Yet, they also find that Nup133’s central domain is required for a properly configured nuclear basket in all NPCs. Keywords: nuclear pore, nucleoporin, NPC scaffold, nuclear basket, biogenesis, dynamics, mouse embryonic stem cells, Nup133, Nup153, Tpr