Targeting G1-S-checkpoint-compromised cancers with cyclin A/B RxL inhibitors.

Small-cell lung cancers (SCLCs) contain near-universal loss-of-function mutations in RB1 and TP53, compromising the G1-S checkpoint and leading to dysregulated E2F activity. Other cancers similarly disrupt the G1-S checkpoint through loss of CDKN2A or amplification of cyclin D or cyclin E, also resulting in excessive E2F activity. Although E2F activation is essential for cell cycle progression, hyperactivation promotes apoptosis, presenting a therapeutic vulnerability.

TDP-43 pathology is associated with divergent protein profiles in ALS brain and spinal cord.

Neuronal and glial cytoplasmic inclusions positive for TAR DNA-binding protein 43 (TDP-43) are the defining pathological hallmark of 97% of amyotrophic lateral sclerosis (ALS) and 50% of frontotemporal dementia (FTD). The ALS-FTD clinicopathological spectrum variably involves cortical and spinal anterior horn cell pathology. The broader protein composition of these inclusions is of major importance to understanding pathogenesis, clinical heterogeneity and biomarker development.

Acidosis attenuates the hypoxic stabilization of HIF-1α by activating lysosomal degradation.

Hypoxia-inducible factors (HIFs) mediate cellular responses to low oxygen, notably enhanced fermentation that acidifies poorly perfused tissues and may eventually become more damaging than adaptive. How pH feeds back on hypoxic signaling is unclear but critical to investigate because acidosis and hypoxia are mechanistically coupled in diffusion-limited settings, such as tumors. Here, we examined the pH sensitivity of hypoxic signaling in colorectal cancer cells that can survive acidosis.

Deep palaeoproteomic profiling of archaeological human brains.

Palaeoproteomics leverages the persistence, diversity, and biological import of ancient proteins to explore the past, and answer fundamental questions about phylogeny, environment, diet, and disease. These insights are largely gleaned from hard tissues like bone and teeth, as well-established protocols exist for extracting ancient proteins from mineralised tissues. No such method, however, exists for the soft tissues, which are underexplored in palaeoproteomics given permission for destructive analysis routinely depends on a proven methodology.

Integrative proximal-ubiquitomics profiling for deubiquitinase substrate discovery applied to USP30.

The growing interest in deubiquitinases (DUBs) as drug targets for modulating critical molecular pathways in disease is fueled by the discovery of their specific cellular roles. A crucial aspect of this fact is the identification of DUB substrates. While mass spectrometry-based proteomic methods can be used to study global changes in cellular ubiquitination following DUB activity perturbation, these datasets often include indirect and downstream ubiquitination events.

Pleural fluid proteomics from patients with pleural infection shows signatures of diverse neutrophilic responses: The Oxford Pleural Infection Endotyping Study (TORPIDS-2).

Background: Pleural infection is a complex disease with poor clinical outcomes and increasing incidence worldwide, yet its biological endotypes remain unknown.

Methods: We analysed 80 pleural fluid samples from the PILOT study, a prospective study on pleural infection, using unlabelled mass spectrometry. A total of 449 proteins were retained after filtering.

Bisphosphonates Trigger Anti-Ageing Effects Across Multiple Cell Types and Protect Against Senescence.

Bisphosphonates (BPs) have been the major class of medicines used to treat disorders of excessive bone loss for over five decades. Recently it has been recognized that BPs may also have additional significant beneficial extra-skeletal effects. These include a reduction of all-cause mortality and of conditions commonly linked to ageing, such as cancer and cardiovascular disease.

ATR-hippo drives force signaling to nuclear F-actin and links mechanotransduction to neurological disorders.

The mechanical environment is sensed through cell-matrix contacts with the cytoskeleton, but how signals transit the nuclear envelope to affect cell fate decisions remains unknown. Nuclear actin coordinates chromatin motility during differentiation and genome maintenance, yet it remains unclear how nuclear actin responds to mechanical force. The DNA-damage kinase ataxia telangiectasia and Rad3-related protein (ATR) translocates to the nuclear envelope to protect the nucleus during cell motility or compression.

Structural Dynamics of the Ubiquitin Specific Protease USP30 in Complex with a Cyanopyrrolidine-Containing Covalent Inhibitor.

Inhibition of the mitochondrial deubiquitinating (DUB) enzyme USP30 is neuroprotective and presents therapeutic opportunities for the treatment of idiopathic Parkinson's disease and mitophagy-related disorders. We integrated structural and quantitative proteomics with biochemical assays to decipher the mode of action of covalent USP30 inhibition by a small-molecule containing a cyanopyrrolidine reactive group, . The inhibitor demonstrated high potency and selectivity for endogenous USP30 in neuroblastoma cells.

Protocol to profile spatially resolved NLRP3 inflammasome complexes using APEX2-based proximity labeling.

The NLRP3 inflammasome is a key multi-protein complex controlling inflammation, particularly interleukin-1β (IL-1β) production. Here, we present a protocol to profile spatially resolved NLRP3 inflammasome complexes using ascorbic peroxidase 2 (APEX2)-based proximity labeling combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS). We describe steps for design and generation of the fusion construct, characterization of the stable FLAG-NLRP3-APEX2 expression cell line by western blotting/imaging, biotinylated proteome enrichment, and mass spectrometry analysis.

TEX264 drives selective autophagy of DNA lesions to promote DNA repair and cell survival.

DNA repair and autophagy are distinct biological processes vital for cell survival. Although autophagy helps maintain genome stability, there is no evidence of its direct role in the repair of DNA lesions. We discovered that lysosomes process topoisomerase 1 cleavage complexes (TOP1cc) DNA lesions in vertebrates.

Cyclin A/B RxL Macrocyclic Inhibitors to Treat Cancers with High E2F Activity.

Cancer cell proliferation requires precise control of E2F1 activity; excess activity promotes apoptosis. Here, we developed cell-permeable and bioavailable macrocycles that selectively kill small cell lung cancer (SCLC) cells with inherent high E2F1 activity by blocking RxL-mediated interactions of cyclin A and cyclin B with select substrates. Genome-wide CRISPR/Cas9 knockout and random mutagenesis screens found that cyclin A/B RxL macrocyclic inhibitors (cyclin A/Bi) induced apoptosis paradoxically by cyclin B- and Cdk2-dependent spindle assembly checkpoint activation (SAC).

Cyclin F-EXO1 axis controls cell cycle-dependent execution of double-strand break repair.

Ubiquitination is a crucial posttranslational modification required for the proper repair of DNA double-strand breaks (DSBs) induced by ionizing radiation (IR). DSBs are mainly repaired through homologous recombination (HR) when template DNA is present and nonhomologous end joining (NHEJ) in its absence. In addition, microhomology-mediated end joining (MMEJ) and single-strand annealing (SSA) provide backup DSBs repair pathways.

HSV-1 employs UL56 to antagonize expression and function of cGAMP channels.

DNA sensing is important for antiviral immunity. The DNA sensor cGAS synthesizes 2'3'-cyclic GMP-AMP (cGAMP), a second messenger that activates STING, which induces innate immunity. cGAMP not only activates STING in the cell where it is produced but cGAMP also transfers to other cells.

Unconventional human CD61 pairing with CD103 promotes TCR signaling and antigen-specific T cell cytotoxicity.

Cancer remains one of the leading causes of mortality worldwide, leading to increased interest in utilizing immunotherapy strategies for better cancer treatments. In the past decade, CD103 T cells have been associated with better clinical prognosis in patients with cancer. However, the specific immune mechanisms contributing toward CD103-mediated protective immunity remain unclear.

Covalent Fragment Screening and Optimization Identifies the Chloroacetohydrazide Scaffold as Inhibitors for Ubiquitin C-terminal Hydrolase L1.

Dysregulation of the ubiquitin-proteasome systems is a hallmark of various disease states including neurodegenerative diseases and cancer. Ubiquitin C-terminal hydrolase L1 (UCHL1), a deubiquitinating enzyme, is expressed primarily in the central nervous system under normal physiological conditions, however, is considered an oncogene in various cancers, including melanoma, lung, breast, and lymphoma. Thus, UCHL1 inhibitors could serve as a viable treatment strategy against these aggressive cancers.

Oncogenic mutations of KRAS modulate its turnover by the CUL3/LZTR1 E3 ligase complex.

KRAS is a proto-oncogene encoding a small GTPase. Mutations contribute to ∼30% of human solid tumours, including lung adenocarcinoma, pancreatic, and colorectal carcinomas. Most KRAS activating mutations interfere with GTP hydrolysis, essential for its role as a molecular switch, leading to alterations in their molecular environment and oncogenic signalling.

BLM and BRCA1-BARD1 coordinate complementary mechanisms of joint DNA molecule resolution.

The Bloom syndrome helicase BLM interacts with topoisomerase IIIα (TOP3A), RMI1, and RMI2 to form the BTR complex, which dissolves double Holliday junctions and DNA replication intermediates to promote sister chromatid disjunction before cell division. In its absence, structure-specific nucleases like the SMX complex (comprising SLX1-SLX4, MUS81-EME1, and XPF-ERCC1) can cleave joint DNA molecules instead, but cells deficient in both BTR and SMX are not viable. Here, we identify a negative genetic interaction between BLM loss and deficiency in the BRCA1-BARD1 tumor suppressor complex.

Data-independent acquisition proteomics of cerebrospinal fluid implicates endoplasmic reticulum and inflammatory mechanisms in amyotrophic lateral sclerosis.

While unbiased proteomics of human cerebrospinal fluid (CSF) has been used successfully to identify biomarkers of amyotrophic lateral sclerosis (ALS), high-abundance proteins mask the presence of lower abundance proteins that may have diagnostic and prognostic value. However, developments in mass spectrometry (MS) proteomic data acquisition methods offer improved protein depth. In this study, MS with library-free data-independent acquisition (DIA) was used to compare the CSF proteome of people with ALS (n = 40), healthy (n = 15) and disease (n = 8) controls.

Structural Premise of Selective Deubiquitinase USP30 Inhibition by Small-Molecule Benzosulfonamides.

Dampening functional levels of the mitochondrial deubiquitylating enzyme Ubiquitin-specific protease 30 (USP30) has been suggested as an effective therapeutic strategy against neurodegenerative disorders such as Parkinson's Disease. USP30 inhibition may counteract the deleterious effects of impaired turnover of damaged mitochondria, which is inherent to both familial and sporadic forms of the disease. Small-molecule inhibitors targeting USP30 are currently in development, but little is known about their precise nature of binding to the protein.