Super-enhancer trapping by the nuclear pore via intrinsically disordered regions of proteins in squamous cell carcinoma cells.

Master transcription factors such as TP63 establish super-enhancers (SEs) to drive core transcriptional networks in cancer cells, yet the spatiotemporal regulation of SEs within the nucleus remains unknown. The nuclear pore complex (NPC) may tether SEs to the nuclear pore where RNA export rates are maximal. Here, we report that NUP153, a component of the NPC, anchors SEs to the NPC and enhances TP63 expression by maximizing mRNA export. This anchoring is mediated through protein-protein interaction between the intrinsically disordered regions (IDRs) of NUP153 and the coactivator BRD4. Silencing of NUP153 excludes SEs from the nuclear periphery, decreases TP63 expression, impairs cellular growth, and induces epidermal differentiation of squamous cell carcinoma. Overall, this work reveals the critical roles of NUP153 IDRs in the regulation of SE localization, thus providing insights into a new layer of gene regulation at the epigenomic and spatial level.

Nuclear transport surveillance of p53 by nuclear pores in glioblastoma.

Nuclear pore complexes (NPCs) are the central apparatus of nucleocytoplasmic transport. Disease-specific alterations of NPCs contribute to the pathogenesis of many cancers; however, the roles of NPCs in glioblastoma (GBM) are unknown. In this study, we report genomic amplification of NUP107, a component of NPCs, in GBM and show that NUP107 is overexpressed simultaneously with MDM2, a critical E3 ligase that mediates p53 degradation. Depletion of NUP107 inhibits the growth of GBM cell lines through p53 protein stabilization. Mechanistically, NPCs establish a p53 degradation platform via an export pathway coupled with 26S proteasome tethering. NUP107 is the keystone for NPC assembly; the loss of NUP107 affects the integrity of the NPC structure, and thus the proportion of 26S proteasome in the vicinity of nuclear pores significantly decreases. Together, our findings establish roles of NPCs in transport surveillance and provide insights into p53 inactivation in GBM.

Nucleoporin TPR (translocated promoter region, nuclear basket protein) upregulation alters MTOR-HSF1 trails and suppresses autophagy induction in ependymoma.

Children with ependymoma have high mortality rates because ependymoma is resistant to conventional therapy. Genomic and transcriptomic studies have identified potential targets as significantly altered genes in ependymoma patients. Although several candidate oncogenes in ependymoma were recently reported, the detailed mechanisms for the roles of these candidate oncogenes in ependymoma progression remain unclear. Here, we report an oncogenic role of the nucleoporin TPR (translocated promoter region, nuclear basket protein) in regulating HSF1 (heat shock transcription factor 1) mRNA trafficking, maintaining MTORC1 activity to phosphorylate ULK1, and preventing macroautophagy/autophagy induction in ependymoma. High expression of TPR were associated with increased HSF1 and HSPA/HSP70 expression in ependymoma patients. In an ependymoma mouse xenograft model, MTOR inhibition by rapamycin therapeutically suppressed TPR expression and reduced tumor size in vivo. Together, these results suggest that TPR may act as a biomarker for ependymoma, and pharmacological interventions targeting TPR-HSF1-MTOR may have therapeutic potential for ependymoma treatment.Abbreviations: ATG: autophagy related; BECN1: beclin 1; BSA: bovine serum albumin; CQ: chloroquine; DMSO: dimethyl sulfoxide; GEO: gene expression omnibus; GFP: green fluorescence protein; HSF1: heat shock transcription factor 1; HSPA/HSP70: heat shock protein family A (Hsp70); LMNB1: lamin B1; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; MAPK: mitogen-activated protein kinase; MAPK8/JNK: mitogen-activated protein kinase 8; MTORC1: mechanistic target of rapamycin kinase complex 1; NPC: nuclear pore complex; NUP: nucleoporin; PBS: phosphate-buffered saline; q-PCR: quantitative real time PCR; SDS: sodium dodecyl sulfate; SQSTM1: sequestosome 1; STED: stimulated emission depletion microscopy; STX17: syntaxin 17; TCGA: the cancer genome atlas; TPR: translocated promoter region, nuclear basket protein; ULK1: unc-51 like autophagy activating kinase 1.

Overexpression of SARS-CoV-2 protein ORF6 dislocates RAE1 and NUP98 from the nuclear pore complex.

The novel human betacoronavirus SARS-CoV-2 has caused an unprecedented pandemic in the 21st century. Several studies have revealed interactions between SARS-CoV-2 viral proteins and host nucleoporins, yet their functions are largely unknown. Here, we demonstrate that the open-reading frame 6 (ORF6) of SARS-CoV-2 can directly manipulate localization and functions of nucleoporins. We found that ORF6 protein disrupted nuclear rim staining of nucleoporins RAE1 and NUP98. Consequently, this disruption caused aberrant nucleocytoplasmic trafficking and led to nuclear accumulation of mRNA transporters such as hnRNPA1. Ultimately, host cell nucleus size was reduced and cell growth was halted.