The nuclear envelope comprises an outer and inner nuclear membrane (ONM and INM) and nucleoporin-containing nuclear pore complexes (NPCs); together, they control nuclear import and export, and the organisation of the genome. Loss of the nucleoporin embryonic large molecule derived from yolk sac (ELYS) has been shown to impair localisation of the INM protein lamin B receptor (LBR) to the reforming nuclear envelope in telophase. Now (p. 4200), Naoko Imamoto and colleagues set out to investigate this relationship in interphase cells. Depletion of ELYS leads to the disruption of LBR localisation at the nuclear envelope and an increase in LBR phosphorylation. The phosphorylation sites in LBR are known targets of cyclin-dependent kinases (CDKs) and serine/arginine protein kinase (SPRK) 1 and 2, and, as shown here, the mislocalisation of LBR upon ELYS depletion can be reversed by the inhibition of CDKs and SRPKs. The authors also show that dephosphorylation of LBR is mediated by protein phosphatase 1 (PP1) and knockdown of PP1 leads to a loss of LBR from the INM. Furthermore, the phosphorylation of LBR facilitates its interaction with nucleoplasm-facing proteins, such as lamin B, heterochromatin protein 1 (HP1) and histone H3, thus restricting its mobility within the nuclear envelope. Taken together, these data suggest that there are phosphorylation-dependent interactions between nucleoporins and INM proteins that control the integrity of the nuclear membrane.