The E3 ubiquitin ligase SCF(Fbxo7) mediates proteasomal degradation of UXT isoform 2 (UXTV2) to inhibit the NF-kappaB signaling pathway
- Author(s)
- Spagnol, V; Oliveira, CAB; Randle, SJ; Passos, PMS; Correia, Crstb; Simaroli, NB; Oliveira, JS; Mevissen, TET; Medeiros, AC; Gomes, MD; Komander, D; Laman, H; Teixeira, FR;
- Journal Title
- Biochimica et Biophysica Acta General Subjects
- Publication Type
- Journal epub ahead of print
- Abstract
- BACKGROUND: Ubiquitously eXpressed Transcript isoform 2 (UXTV2) is a prefoldin-like protein involved in NF-kappaB signaling, apoptosis, and the androgen and estrogen response. UXT-V2 is a cofactor in the NF-kappaB transcriptional enhanceosome, and its knockdown inhibits TNF-alpha -induced NF-kappaB activation. Fbxo7 is an F-box protein that interacts with SKP1, Cullin1 and RBX1 proteins to form an SCF(Fbxo7) E3 ubiquitin ligase complex. Fbxo7 negatively regulates NF-kappaB signaling through TRAF2 and cIAP1 ubiquitination. METHODS: We combine Co-immunoprecipitation, ubiquitination in vitro and in vivo, cycloheximide chase assay, Ubiquitin chain restriction analysis and microscopy to investigate interaction between Fbxo7 and overexpressed UXT-V2-HA. RESULTS: The Ubl domain of Fbxo7 contributes to interaction with UXTV2. This substrate is polyubiquitinated by SCF(Fbxo7) with K48 and K63 ubiquitin chain linkages in vitro and in vivo. This post-translational modification decreases UXT-V2 stability and promotes its proteasomal degradation. We further show that UXTV1, an alternatively spliced isoform of UXT, containing 12 additional amino acids at the N-terminus as compared to UXTV2, also interacts with and is ubiquitinated by Fbxo7. Moreover, FBXO7 knockdown promotes UXT-V2 accumulation, and the overexpression of Fbxo7-DeltaF-box, protects UXT-V2 from proteasomal degradation and enhances the responsiveness of NF-kappaB reporter. We find that UXT-V2 colocalizes with Fbxo7 in the cell nucleus. CONCLUSIONS: Together, our study reveals that SCF(Fbxo7) mediates the proteasomal degradation of UXT-V2 causing the inhibition of the NF-kappaB signaling pathway. GENERAL SIGNIFICANCE: Discovering new substrates of E3 ubiquitin-ligase SCF(Fbxo7) contributes to understand its function in different diseases such as cancer and Parkinson.
- Publisher
- Elsevier
- Research Division(s)
- Ubiquitin Signalling
- PubMed ID
- 33010352
- Publisher's Version
- https://doi.org/10.1016/j.bbagen.2020.129754
- Terms of Use/Rights Notice
- Refer to copyright notice on published article.
Creation Date: 2020-10-17 02:40:32
Last Modified: 2020-11-03 09:50:59