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The crystal structures of thalidomide and its derivatives bound to the E3 ligase subcomplex DDB1–CRBN are shown; these drugs are found to have dual functions, interfering with the binding of certain cellular substrates to the E3 ligase but promoting the binding of others, thereby modulating the degradation of cellular proteins.

Much of the intracellular protein degradation in eukaryotes is controlled by cullin–RING ubiquitin ligases (CRLs), a vast class of enzymes which are regulated by the COP9 signalosome (CSN); structural characterization of CSN–N8CRL4A complexes by cryo-electron microscopy reveals an induced-fit mechanism of CSN activation triggered only by catalytically activated CRLs without bound substrate, explaining how CSN acts as a global regulator of CRLs.

The COP9 signalosome (CSN) complex regulates cullin–RING E3 ubiquitin ligases—the largest class of ubiquitin ligase enzymes, which are involved in a multitude of regulatory processes; here, the crystal structure of the entire human CSN holoenzyme is presented.

Thalidomide and its derivative lenalidomide bind the CRL4^CRBN E3 ubiquitin ligase and target protein substrates for degradation; structural and functional data determined here show that casein kinase 1α and the lymphoid transcription factor Ikaros, the efficacy targets of lenalidomide in two different blood cancers, interact with the CRBN–lenalidomide interface through a β-hairpin destruction motif.

BMAL1–HIF2α heterodimer was recently shown to modulate circadian variations in myocardial injury. Here, the authors show that BMAL1 can form a heterodimer with HIF2α in clear cell renal cell carcinoma, contributing to tumor progression and response to HIF2α antagonist drugs.

Detailed analysis of the structure–activity relationship for cyclin K degraders reveals diverse compounds that acquire glue activity through simultaneous binding to the CDK12 kinase pocket and engagement of several key DDB1 interfacial residues.

Targeted protein degradation (TPD) is a key modality for drug discovery. Here the authors present the discovery and analysis of reversible DCAF1-PROTACs, which show efficacy in cellular environments resistant to VHL-PROTACs or with acquired resistance to CRBN-PROTACs.

Using cryo-electron microscopy, the authors determine the structure of cGAS bound to nucleosomes and present evidence for the mechanism by which nucleosome binding to cGAS prevents cGAS dimerization and its binding to free double-stranded DNA.

Structure determination and functional analyses of budding yeast Rif1 reveal a novel, hooked N-terminal DNA-binding domain required for telomere maintenance and checkpoint control and show that Rif1's role in DNA-repair pathway choice is conserved in yeast and mammalian cells.

The 'dissolvasome', composed of TopIIIα, BLM and RMI proteins, coordinates DNA-helicase and DNA-topoisomerase activities to resolve double Holliday junctions (dHJs) generated during DNA recombination and repair. The first crystal structure of a human TopIIIα–Rmi1 subcomplex provides insights into how topoisomerase is stimulated to promote dHJ decatenation.

Cryo-electron microscopy structures reveal that the DNA-repair factor UV-DDB exposes inaccessible nucleosome lesions for binding by inducing a translational shift in the nucleosome position.

Cryo-EM structures and analysis provide insight into the mechanisms by which basic helix–loop–helix transcription factors access E-box DNA sequences that are embedded within nucleosomes, and cooperate with other transcription factors.

The presence of Trim24 increases cell viability upon stress and enables p53 to influence gene expression as a function of the local chromatin state.

The cyclin-dependent kinase inhibitor CR8 acts as a molecular glue compound by inducing the formation of a complex between CDK12–cyclin K and DDB1, which results in the ubiquitination and degradation of cyclin K.

Proteolysis-targeting chimera (PROTACs) are synthetic molecules that recruit neo-substrate proteins to a ubiquitin ligase for ubiquitination and subsequent degradation. Structural insight into the VHL–MZ1–BRD4 complex reveals how the rationally designed MZ1–PROTAC molecule mediates degradation of an unnatural protein substrate.

Structural elucidation and functional analyses of the CIA targeting complex (CTC) bound to DNA2 and primase illuminate the mechanism of cytoplasmic Fe–S cluster transfer to client proteins.

Rif1 is involved in different processes such as telomere homeostasis, DNA replication timing, and DNA double strand break (DSB) repair pathway choice. Here, the authors reveal that Rif1 S-acylation facilitates the accumulation of Rif1 at DSBs, attenuation of DNA end-resection, and DSB repair by non-homologous end-joining.

BANP is identified as the transcription factor that binds the CGCG element in a DNA-methylation-dependent manner, opens chromatin and activates a class of essential CpG-island-regulated genes.

Chemical profiling in hyponeddylated cells coupled with multi-omics target deconvolution led to the identification of molecular glue degraders of cyclin K that function by inducing proximity between the CRL adaptor DDB1 and a CDK12–cyclin K complex.

It has previously been established that DNA end resection in yeast and in humans is under CDK control. Here the authors explain how phosphorylation regulates the capacity of Sae2 — the yeast orthologue of human CtIP — to promote DNA end resection.

Genome-scale methods are providing increasingly detailed views of nucleosome organization and chromatin structure. This is enhancing our understanding of how DNA-based reactions occur in the context of chromatin and how they are influenced by genome accessibility.

ADNP interacts with the chromatin remodeller CHD4 and the heterochromatin protein HP1 to form a complex termed ChAHP that represses gene expression independently of the histone H3K9me3 modification.