Liu et al. define how the CRL2ZYG11B ubiquitin ligase assembles and recognizes Gly/N-degron substrates by cryo-EM. Structures with an NLRP1 Gly/N-degron and SARS-CoV-2 ORF10 reveal extended substrate-...

Selected proteins containing an N-terminal cysteine (Nt-Cys) are subjected to rapid, O2-dependent proteolysis via the Cys/Arg-branch of the N-degro...

Abstract. Recent discoveries have fundamentally transformed the paradigm of plant oxygen sensing. Hypoxia is no longer viewed solely because of environment

Deubiquitylases are key proteolytic regulators of ubiquitin-dependent cellular processes, catalyzing the removal or remodelling of ubiquitin modifications on substrate proteins, including those target...

CTCF is an essential DNA binding protein whose absence leads to embryonic lethality. CTCF is primarily known for its role in 3D genome organization where its N-terminal domain interacts with cohesin to anchor chromatin loops. How CTCF facilitates proper embryonic development remains unclear, necessitating temporal control to resolve its stage-specific functions. By combining gastruloids, an in vitro model of embryonic development, with a degron system to rapidly deplete CTCF at defined timepoints, we show that early CTCF depletion impairs early gastruloid morphogenesis. Surprisingly, ATAC-seq and time-resolved RNA-seq revealed that differentiation was unaffected. CTCF binding is strongly enriched at promoters of downregulated genes. Re-expression of a CTCF variant with an N-terminal truncation, incapable of looping, was sufficient to rescue the expression of CTCF-promoter bound genes and the defects in morphogenesis. However, extended culture (up to 168 hours) of gastruloids reconstituted with N-terminal truncated CTCF led to their collapse. Our work shows that CTCF has a dual function in early mammalian development: at early stages CTCF regulates developmentally important genes through promoter binding, while at later stages its looping function is required for correct development. ### Competing Interest Statement The authors have declared no competing interest. European Research Council, https://ror.org/0472cxd90, 637587, 865459 Dutch Research Council, https://ror.org/04jsz6e67, 016.161.316, VI.C.222.049 Dutch Cancer Society, https://ror.org/0368jnd28, N/A

The N-degron pathway is essential for protein quality control and cellular homeostasis. GID4, a subunit of the GID ubiquitin ligase, is the main recog…

Although it is known that penultimate N-terminal residues can influence protein stability by the N-degron pathway, there has not been a comprehensive effort to document nor predict these effects for n...

Abstract. Recent discoveries have fundamentally transformed the paradigm of plant oxygen sensing. Hypoxia is no longer viewed solely because of environment

Deubiquitylases are key proteolytic regulators of ubiquitin-dependent cellular processes, catalyzing the removal or remodelling of ubiquitin modifications on substrate proteins, including those target...

Coenzyme A (CoA) is an essential metabolic cofactor whose biosynthesis is controlled by pantothenate kinases (PANKs), the rate-limiting enzymes in CoA synthesis. Although CoA production is extensively...

The ubiquitin-dependent Arg/N-degron pathway relates the stability of a substrate protein to the nature of its N-terminal amino acid residue or its biochemical modifications, with some N-terminal residues being recognized by specific E3 ubiquitin ligases, resulting in the ubiquitylation and degradation of the substrate protein. Work in the model plant Arabidopsis thaliana has shown that the Arg/N-degron pathway is a key regulator of plant responses to hypoxia, which can be either physiological or a stress in the context of waterlogging or submergence. The role of the Arg/N-degron pathway in hypoxia response is mediated via the oxygen-dependent degradation of group VII ETHYLENE RESPONSE FACTOR (ERFVII) transcription factors, which act as the master regulators of the hypoxia response program in plants. Analysis of Arabidopsis mutants for different enzymatic components of the Arg/N-degron pathway has also revealed its roles in the regulation of responses to other abiotic stresses (e.g. salt stress), as well as to pathogens. Although much has been learned from studies in Arabidopsis about the functions of the Arg/N-degron pathway, very little is known about this pathway in crops, including in Brassica crops such as oilseed rape, cabbage or turnip. To determine functional similarities and divergence of the Arg/N-degron pathway between Arabidopsis and Brassica crops, we isolated and characterized the first Arg/N-degron pathway mutants in Brassica rapa (turnip, pak choi), a diploid Brassica crop closely related to oilseed rape. We focused on two enzymatic components, namely the arginine-transferases ( ATE s) and the E3 ubiquitin ligase PROTEOLYSIS6 ( PRT6 ). Our results show both similarities and divergence of function for these Arg/N-degron pathway components in B. rapa compared to Arabidopsis. Specifically, ATE mutants in B. rapa arrest their development at the seedling stage, which contrasts with the mild phenotypic defects of the equivalent Arabidopsis mutants. Double mutant lines for two of the three PRT6 genes in B. rapa indicated a constitutive activation of hypoxia response genes at the transcriptional level, as shown in the single prt6 mutant in Arabidopsis. However, contrary to Arabidopsis, the B. rapa double mutants were more sensitive to waterlogging and hypoxia, and did not show differential response to salt stress or to biotic stress compared to the wild type. The functional divergence identified likely reflects variability in each species in the substrate repertoire and/or in the regulation of pathways or targets downstream of Arg/N-degron pathway substrates. Such differences could be driven by direct selective pressures at N-termini (e.g. gain or loss of a destabilizing N-terminal residue), or by species-specific proteases that may generate destabilizing neo-N-termini after cleavage. These similarities and differences highlight the difficulties in translating research findings from Arabidopsis to crops, even within the same plant family (Brassicaceae) and highlight the need to study pathways in crops. ### Competing Interest Statement The authors have declared no competing interest. Science Foundation Ireland, https://ror.org/0271asj38, 13/IA/1870, 20/FFP-P/8433 Irish Research Council, https://ror.org/051xex213, GOIPG/2017/2

N-terminal methionine formylation, a protein modification once thought to be exclusive to bacteria and organelles, also occurs on proteins synthesized in the cytosol of yeast and human cells, challeng...

The Arg/N-degron pathway of Saccharomyces cerevisiae is mediated by two interacting E3 ubiquitin ligases, Ubr1 and Ufd4. We show here that the mito...

Abstract. Recent discoveries have fundamentally transformed the paradigm of plant oxygen sensing. Hypoxia is no longer viewed solely because of environment