Targeted protein degradation (TPD) refers to the use of small molecules to induce ubiquitin-dependent degradation of proteins. TPD is of interest in drug development, as it can address previously ...inaccessible targets. However, degrader discovery and optimization remains an inefficient process due to a lack of understanding of the relative importance of the key molecular events required to induce target degradation. Here, we use chemo-proteomics to annotate the degradable kinome. Our expansive dataset provides chemical leads for ∼200 kinases and demonstrates that the current practice of starting from the highest potency binder is an ineffective method for discovering active compounds. We develop multitargeted degraders to answer fundamental questions about the ubiquitin proteasome system, uncovering that kinase degradation is p97 dependent. This work will not only fuel kinase degrader discovery, but also provides a blueprint for evaluating targeted degradation across entire gene families to accelerate understanding of TPD beyond the kinome.
Display omitted
•A global map of kinase degradability provides chemical leads for >200 kinases•Open-access chemical proteomics resource (https://proteomics.fischerlab.org)•Large-scale chemical exploration of key variables for targeted protein degradation•Multi-targeted degraders uncover fundamentals of ubiquitin-mediated protein turnover
A synthetic chemistry and chemo-proteomics platform used to annotate the “degradable kinome” provides chemical leads for developing degraders of approximately 200 distinct kinase targets and offers new general design principles for developing future kinase degraders.
HECT ubiquitin ligases play essential roles in metazoan development and physiology. The HECT ligase HUWE1 is central to the cellular stress response by mediating degradation of key death or survival ...factors, including Mcl1, p53, DDIT4, and Myc. Although mutations in HUWE1 and related HECT ligases are widely implicated in human disease, our molecular understanding remains limited. Here we present a comprehensive investigation of full-length HUWE1, deepening our understanding of this class of enzymes. The N-terminal ∼3,900 amino acids of HUWE1 are indispensable for proper ligase function, and our cryo-EM structures of HUWE1 offer a complete molecular picture of this large HECT ubiquitin ligase. HUWE1 forms an alpha solenoid-shaped assembly with a central pore decorated with protein interaction modules. Structures of HUWE1 variants linked to neurodevelopmental disorders as well as of HUWE1 bound to a model substrate link the functions of this essential enzyme to its three-dimensional organization.
Display omitted
•Structure of a full-length HECT ligase reveals modular assembly•HUWE1 folds into ring-shaped architecture with flexibly attached accessory domains•Patient mutations interfere with HUWE1 ligase activity•Armadillo repeats in the ring architecture contribute to substrate binding
Hunkeler et al. present the cryo-EM structure of HUWE1, a large HECT E3 ligase that forms a modular ring-shaped assembly with flexibly attached accessory domains. The influence of mutations associated with intellectual disabilities on HUWE1 activity and substrate recognition by HUWE1 is dissected biochemically and structurally.
Identification of melanoma patients at high risk for recurrence and monitoring for recurrence are critical for informed management decisions. We hypothesized that serum microRNAs (miRNAs) could ...provide prognostic information at the time of diagnosis unaccounted for by the current staging system and could be useful in detecting recurrence after resection.
We screened 355 miRNAs in sera from 80 melanoma patients at primary diagnosis (discovery cohort) using a unique quantitative reverse transcription-PCR (qRT-PCR) panel. Cox proportional hazard models and Kaplan-Meier recurrence-free survival (RFS) curves were used to identify a miRNA signature with prognostic potential adjusting for stage. We then tested the miRNA signature in an independent cohort of 50 primary melanoma patients (validation cohort). Logistic regression analysis was performed to determine if the miRNA signature can determine risk of recurrence in both cohorts. Selected miRNAs were measured longitudinally in subsets of patients pre-/post-operatively and pre-/post-recurrence.
A signature of 5 miRNAs successfully classified melanoma patients into high and low recurrence risk groups with significant separation of RFS in both discovery and validation cohorts (p = 0.0036, p = 0.0093, respectively). Significant separation of RFS was maintained when a logistic model containing the same signature set was used to predict recurrence risk in both discovery and validation cohorts (p < 0.0001, p = 0.033, respectively). Longitudinal expression of 4 miRNAs in a subset of patients was dynamic, suggesting miRNAs can be associated with tumor burden.
Our data demonstrate that serum miRNAs can improve accuracy in identifying primary melanoma patients with high recurrence risk and in monitoring melanoma tumor burden over time.
Tank-binding kinase (TBK)1 plays a central role in innate immunity: it serves as an integrator of multiple signals induced by receptormediated pathogen detection and as a modulator of IFN levels. ...Efforts to better understand the biology of this key immunological factor have intensified recently as growing evidence implicates aberrant TBK1 activity in a variety of autoimmune diseases and cancers. Nevertheless, key molecular details of TBK1 regulation and substrate selection remain unanswered. Here, structures of phosphorylated and unphosphorylated human TBK1 kinase and ubiquitin-like domains, combined with biochemical studies, indicate a molecular mechanism of activation via transautophosphorylation. These TBK1 structures are consistent with the tripartite architecture observed recently for the related kinase IKKß, but domain contributions toward target recognition appear to differ for the two enzymes. In particular, both TBK1 autoactivation and substrate specificity are likely driven by signal-dependent colocalization events.
HUWE1 is a large, enigmatic HECT-domain ubiquitin ligase implicated in the regulation of diverse pathways, including DNA repair, apoptosis, and differentiation. How HUWE1 engages its structurally ...diverse substrates and how HUWE1 activity is regulated are unknown. Using unbiased quantitative proteomics, we find that HUWE1 targets substrates in a largely cell-type-specific manner. However, we identify C16orf72/HAPSTR1 as a robust HUWE1 substrate in multiple cell lines. Previously established physical and genetic interactions between HUWE1 and HAPSTR1 suggest that HAPSTR1 positively regulates HUWE1 function. Here, we show that HAPSTR1 is required for HUWE1 nuclear localization and nuclear substrate targeting. Nuclear HUWE1 is required for both cell proliferation and modulation of stress signaling pathways, including p53 and nuclear factor κB (NF-κB)-mediated signaling. Combined, our results define a role for HAPSTR1 in gating critical nuclear HUWE1 functions.
Display omitted
•HUWE1 substrates are diverse and largely cell-type specific•HAPSTR1/C16orf72 is a HUWE1 substrate in multiple cell lines•HAPSTR1 localizes HUWE1 to the nucleus•Nuclear HUWE1 is required for cell proliferation and modulates p53 and NF-κB pathways
Monda et al. find that the substrates of the ubiquitin ligase, HUWE1, are diverse and largely cell-type specific. HAPSTR1 is a robust substrate of HUWE1 and is required for nuclear localization of HUWE1. Nuclear HUWE1 is required for cell proliferation and modulation of stress signaling pathways.
Mainly severe (CTCAE grade 3-4) haematotoxicity during peptide receptor radionuclide therapy (PRRT) is reported in literature due to major clinical impact, however moderate (CTCAE grade 2) ...haematotoxicity is common and could affect therapy management. The aim of this study was to evaluate the haematotoxicity course during PRRT and to compare baseline parameters between haematotoxicity grades.
In this retrospective study, 100 patients with a neuroendocrine tumour treated with PRRT were included. Patients were treated with an aimed number of four cycles with 7.4 GBq 177LuLu-DOTA-TATE administered every 10 weeks. Haematological assessment was performed at baseline and frequently up to 10 weeks after the fourth cycle. The lowest haematological value was graded according to CTCAE v5.0, and patients were classified using the highest observed grade. Differences in baseline parameters, including 68GaGa-DOTA-TATE positive tumour volume, were evaluated between CTCAE grades.
Four cycles were completed by 86/100 of patients, 4/100 patients discontinued due to haematotoxicity, and 10/100 patients due to progressive disease. The treatment course was adjusted due to haematotoxicity in 24/100 patients, including postponed next cycle (n = 17), reduced administered activity (n = 13), and both adjustments (n = 10). The most observed haematotoxicity grade was grade 0-1 in 54/100 patients, grade 2 in 38/100 and grade 3-4 in 8/100. Significant differences in baseline leucocyte, neutrophil and platelet counts were observed between grade 0-1 and grade 2. However, the correlation between baseline and lowest observed values was poor to moderate. No differences between haematotoxicity grades and baseline parameters or somatostatin receptor positive tumour volume was observed.
The incidence of severe haematotoxicity was low with extensive screening and monitoring. The vast majority of patients (96/100) was not restricted in treatment continuation by haematotoxicity; therefore, our selection criteria appeared appropriate for safe PRRT treatment. Baseline parameters showed limited correlation with the degree of decline in haematological values.
During replication of herpesviruses, capsids escape from the nucleus into the cytoplasm by budding at the inner nuclear membrane. This unusual process is mediated by the viral nuclear egress complex ...(NEC) that deforms the membrane around the capsid by oligomerizing into a hexagonal, membrane-bound scaffold. Here, we found that highly basic membrane-proximal regions (MPRs) of the NEC alter lipid order by inserting into the lipid headgroups and promote negative Gaussian curvature. We also find that the electrostatic interactions between the MPRs and the membranes are essential for membrane deformation. One of the MPRs is phosphorylated by a viral kinase during infection, and the corresponding phosphomimicking mutations block capsid nuclear egress. We show that the same phosphomimicking mutations disrupt the NEC-membrane interactions and inhibit NEC-mediated budding
, providing a biophysical explanation for the
phenomenon. Our data suggest that the NEC generates negative membrane curvature by both lipid ordering and protein scaffolding and that phosphorylation acts as an off switch that inhibits the membrane-budding activity of the NEC to prevent capsid-less budding.
Herpesviruses are large viruses that infect nearly all vertebrates and some invertebrates and cause lifelong infections in most of the world's population. During replication, herpesviruses export their capsids from the nucleus into the cytoplasm by an unusual mechanism in which the viral nuclear egress complex (NEC) deforms the nuclear membrane around the capsid. However, how membrane deformation is achieved is unclear. Here, we show that the NEC from herpes simplex virus 1, a prototypical herpesvirus, uses clusters of positive charges to bind membranes and order membrane lipids. Reducing the positive charge or introducing negative charges weakens the membrane deforming ability of the NEC. We propose that the virus employs electrostatics to deform nuclear membrane around the capsid and can control this process by changing the NEC charge through phosphorylation. Blocking NEC-membrane interactions could be exploited as a therapeutic strategy.
Objective
To assess the impact of COVID‐19 on trends in postpartum mental health diagnoses and utilization of psychotherapy and prescription drug treatment.
Data Sources
Data were obtained from a ...large, national health insurance claims database that tracks individuals longitudinally.
Study Design
We used interrupted time series models to examine changes in trends of postpartum mental health diagnoses before and during the COVID‐19 pandemic and t‐tests to examine differences in treatment.
Data Extraction Methods
We used billing codes to identify individuals who received mental health‐related diagnoses and treatment in the first 90 days after a birth hospitalization. We excluded individuals diagnosed with schizophrenia or bipolar disorder and those with an unknown payer at delivery.
Principal Findings
Compared to the pre‐pandemic period, the trend in new postpartum mental health diagnoses increased significantly in the post‐COVID‐19 period (0.06 percentage points 95%CI 0.01, 0.11). Over 12 months, the percentage of new diagnoses was 5.0% greater relative to what would be expected in absence of COVID‐19. The percentage of diagnosed individuals who did not receive treatment increased from 50.4% to 52.7% (p = 0.003).
Conclusions
Findings point to an urgent need to improve screening and treatment pathways for perinatal individuals in the wake of COVID‐19.
The sentinel lymph node is the initial site of metastasis. Downregulation of antitumor immunity has a role in nodal progression. Our objective was to investigate the relationship between immune ...modulation and sentinel lymph node positivity, correlating it with outcome in melanoma patients. Lymph node/primary tissues from melanoma patients prospectively accrued and followed at New York University Medical Center were evaluated for the presence of regulatory T cells (Foxp3+) and dendritic cells (conventional: CD11c+, mature: CD86+) using immunohistochemistry. Primary melanoma immune cell profiles from sentinel lymph node-positive/-negative patients were compared. Logistic regression models inclusive of standard-of-care/immunological primary tumor characteristics were constructed to predict the risk of sentinel lymph node positivity. Immunological responses in the positive sentinel lymph node were also compared with those in the negative non-sentinel node from the same nodal basin and matched negative sentinel lymph node. Decreased immune response was defined as increased regulatory T cells or decreased dendritic cells. Associations between the expression of these immune modulators, clinicopathological variables, and clinical outcome were evaluated using univariate/multivariate analyses. Primary tumor conventional dendritic cells and regression were protective against sentinel lymph node metastasis (odds ratio=0.714, 0.067; P=0.0099, 0.0816, respectively). Antitumor immunity was downregulated in the positive sentinel lymph node with an increase in regulatory T cells compared with the negative non-sentinel node from the same nodal basin (P=0.0005) and matched negative sentinel lymph node (P=0.0002). The positive sentinel lymph node also had decreased numbers of conventional dendritic cells compared with the negative sentinel lymph node (P<0.0001). Adding sentinel lymph node regulatory T cell expression improved the discriminative power of a recurrence risk assessment model using clinical stage. Primary tumor regression was associated with prolonged disease-free (P=0.025) and melanoma-specific (P=0.014) survival. Our results support an assessment of local immune profiles in both the primary tumor and sentinel lymph node to help guide therapeutic decisions.
PDF
