Osh proteins regulate phosphoinositide metabolism at ER-plasma membrane contact sites.

Sac1 phosphoinositide (PI) phosphatases are essential regulators of PI-signaling networks. Yeast Sac1, an integral endoplasmic reticulum (ER) membrane protein, controls PI4P levels at the ER, Golgi, and plasma membrane (PM). Whether Sac1 can act in trans and turn over PI4P at the Golgi and PM from the ER remains a paradox. We find that Sac1-mediated PI4P metabolism requires the oxysterol-binding homology (Osh) proteins. The PH domain-containing family member, Osh3, localizes to PM/ER membrane contact sites dependent upon PM PI4P levels. We reconstitute Osh protein-stimulated Sac1 PI phosphatase activity in vitro. We also show that the ER membrane VAP proteins, Scs2/Scs22, control PM PI4P levels and Sac1 activity in vitro. We propose that Osh3 functions at ER/PM contact sites as both a sensor of PM PI4P and an activator of the ER Sac1 phosphatase. Our findings further suggest that the conserved Osh proteins control PI metabolism at additional membrane contact sites.

Membrane-dependent actin polymerization mediated by the Legionella pneumophila effector protein MavH.

L. pneumophila propagates in eukaryotic cells within a specialized niche, the Legionella-containing vacuole (LCV). The infection process is controlled by over 330 effector proteins delivered through the type IV secretion system. In this study, we report that the Legionella MavH effector localizes to endosomes and remodels host actin cytoskeleton in a phosphatidylinositol 3-phosphate (PI(3)P) dependent manner when ectopically expressed. We show that MavH recruits host actin capping protein (CP) and actin to the endosome via its CP-interacting (CPI) motif and WH2-like actin-binding domain, respectively. In vitro assays revealed that MavH stimulates actin assembly on PI(3)P-containing liposomes causing their tubulation. In addition, the recruitment of CP by MavH negatively regulates F-actin density at the membrane. We further show that, in L. pneumophila-infected cells, MavH appears around the LCV at the very early stage of infection and facilitates bacterium entry into the host. Together, our results reveal a novel mechanism of membrane tubulation induced by membrane-dependent actin polymerization catalyzed by MavH that contributes to the early stage of L. pneumophila infection by regulating host actin dynamics.

Mechanism of phosphoribosyl-ubiquitination mediated by a single Legionella effector.

Ubiquitination is a post-translational modification that regulates many cellular processes in eukaryotes1-4. The conventional ubiquitination cascade culminates in a covalent linkage between the C terminus of ubiquitin (Ub) and a target protein, usually on a lysine side chain1,5. Recent studies of the Legionella pneumophila SidE family of effector proteins revealed a ubiquitination method in which a phosphoribosyl ubiquitin (PR-Ub) is conjugated to a serine residue on substrates via a phosphodiester bond6-8. Here we present the crystal structure of a fragment of the SidE family member SdeA that retains ubiquitination activity, and determine the mechanism of this unique post-translational modification. The structure reveals that the catalytic module contains two distinct functional units: a phosphodiesterase domain and a mono-ADP-ribosyltransferase domain. Biochemical analysis shows that the mono-ADP-ribosyltransferase domain-mediated conversion of Ub to ADP-ribosylated Ub (ADPR-Ub) and the phosphodiesterase domain-mediated ligation of PR-Ub to substrates are two independent activities of SdeA. Furthermore, we present two crystal structures of a homologous phosphodiesterase domain from the SidE family member SdeD 9 in complexes with Ub and ADPR-Ub. The structures suggest a mechanism for how SdeA processes ADPR-Ub to PR-Ub and AMP, and conjugates PR-Ub to a serine residue in substrates. Our study establishes the molecular mechanism of phosphoribosyl-linked ubiquitination and will enable future studies of this unusual type of ubiquitination in eukaryotes.

Experience of undergraduate nursing students participating in artificial intelligence + project task driven learning at different stages: a qualitative study.

BACKGROUND: Artificial intelligence is a growing phenomenon that will soon facilitate wide-scale changes in many professions, and is expected to play an important role in the field of medical education. This study explored the realistic feelings and experiences of nursing undergraduates participating in different stages of artificial intelligence + project task driven learning, and provide a basis for artificial intelligence participation in nursing teaching. METHODS: We conducted face-to-face semi-structured interviews with nursing undergraduates participating in Nursing Research Course which adopts artificial intelligence + project task driven learning from a medical university in Ningxia from September to November 2023, to understand their experience of using artificial intelligence for learning and the emotional changes at different stages. The interview guide included items about their personal experience and feelings of completing project tasks through dialogue with artificial intelligence, and suggestions for course content. Thematic analysis was used to analyze interview data. This study followed the COREQ checklist. RESULTS: According to the interview data, three themes were summarized. Undergraduate nursing students have different experiences in participating in artificial intelligence + project task driven learning at different stages, mainly manifested as diverse emotional experiences under initial knowledge deficiency, the individual growth supported by external forces during the adaptation period, and the expectations and suggestions after the birth of the results in the end period. CONCLUSIONS: Nursing undergraduates can actively adapt to the integration of artificial intelligence into nursing teaching, dynamically observe students' learning experience, strengthen positive guidance, and provide support for personalized teaching models, better leveraging the advantages of artificial intelligence participation in teaching.

A Sugar Transporter Takes Up both Hexose and Sucrose for Sorbitol-Modulated In Vitro Pollen Tube Growth in Apple.

Rapid pollen tube growth requires uptake of Suc or its hydrolytic products, hexoses, from the apoplast of surrounding tissues in the style. Due to species-specific sugar requirements, reliance of pollen germination and tube growth on cell wall invertase and Suc or hexose transporters varies between species, but it is not known if plants have a sugar transporter that mediates the uptake of both hexose and Suc for pollen tube growth. Here, we show that a sugar transporter protein in apple (Malus domestica), MdSTP13a, takes up both hexose and Suc when expressed in yeast, and is essential for pollen tube growth on Glc and Suc but not on maltose. MdSTP13a-mediated direct uptake of Suc is primarily responsible for apple pollen tube growth on Suc medium. Sorbitol, a major photosynthate and transport carbohydrate in apple, modulates pollen tube growth via the MYB transcription factor MdMYB39L, which binds to the promoter of MdSTP13a to activate its expression. Antisense repression of MdSTP13a blocks sorbitol-modulated pollen tube growth. These findings demonstrate that MdSTP13a takes up both hexose and Suc for sorbitol-modulated pollen tube growth in apple, revealing a situation where acquisition of sugars for pollen tube growth is regulated by a sugar alcohol.

Structural basis of peptidoglycan endopeptidase regulation.

Most bacteria surround themselves with a cell wall, a strong meshwork consisting primarily of the polymerized aminosugar peptidoglycan (PG). PG is essential for structural maintenance of bacterial cells, and thus for viability. PG is also constantly synthesized and turned over; the latter process is mediated by PG cleavage enzymes, for example, the endopeptidases (EPs). EPs themselves are essential for growth but also promote lethal cell wall degradation after exposure to antibiotics that inhibit PG synthases (e.g., ß-lactams). Thus, EPs are attractive targets for novel antibiotics and their adjuvants. However, we have a poor understanding of how these enzymes are regulated in vivo, depriving us of novel pathways for the development of such antibiotics. Here, we have solved crystal structures of the LysM/M23 family peptidase ShyA, the primary EP of the cholera pathogen Vibrio cholerae Our data suggest that ShyA assumes two drastically different conformations: a more open form that allows for substrate binding and a closed form, which we predicted to be catalytically inactive. Mutations expected to promote the open conformation caused enhanced activity in vitro and in vivo, and these results were recapitulated in EPs from the divergent pathogens Neisseria gonorrheae and Escherichia coli Our results suggest that LysM/M23 EPs are regulated via release of the inhibitory Domain 1 from the M23 active site, likely through conformational rearrangement in vivo.

Deubiquitination of phosphoribosyl-ubiquitin conjugates by phosphodiesterase-domain-containing Legionella effectors.

Posttranslational protein modification by ubiquitin (Ub) is a central eukaryotic mechanism that regulates a plethora of physiological processes. Recent studies unveiled an unconventional type of ubiquitination mediated by the SidE family of Legionella pneumophila effectors, such as SdeA, that catalyzes the conjugation of Ub to a serine residue of target proteins via a phosphoribosyl linker (hence named PR-ubiquitination). Comparable to the deubiquitinases in the canonical ubiquitination pathway, here we show that 2 paralogous Legionella effectors, Lpg2154 (DupA; deubiquitinase for PR-ubiquitination) and Lpg2509 (DupB), reverse PR-ubiquitination by specific removal of phosphoribosyl-Ub from substrates. Both DupA and DupB are fully capable of rescuing the Golgi fragmentation phenotype caused by exogenous expression of SdeA in mammalian cells. We further show that deletion of these 2 genes results in significant accumulation of PR-ubiquitinated species in host cells infected with Legionella In addition, we have identified a list of specific PR-ubiquitinated host targets and show that DupA and DupB play a role in modulating the association of PR-ubiquitinated host targets with Legionella-containing vacuoles. Together, our data establish a complete PR-ubiquitination and deubiquitination cycle and demonstrate the intricate control that Legionella has over this unusual Ub-dependent posttranslational modification.

An Optimized Probabilistic Delay Tolerant Network (DTN) Routing Protocol Based on Scheduling Mechanism for Internet of Things (IoT).

Many applications of Internet of Things (IoT) have been implemented based on unreliable wireless or mobile networks like the delay tolerant network (DTN). Therefore, it is an important issue for IoT applications to achieve efficient data transmission in DTN. In order to improve delivery rate and optimize delivery delay with low overhead in DTN for IoT applications, we propose a new routing protocol, called Scheduling-Probabilistic Routing Protocol using History of Encounters and Transitivity (PROPHET). In this protocol, we calculate the delivery predictability according to the encountering frequency among nodes. Two scheduling mechanisms are proposed to extend the traditional PROPHET protocol and improve performance in both storage and transmission in DTN. In order to evaluate the proposed routing protocol, we perform simulations and compare it with other routing protocols in an Opportunistic Network Environment (ONE) simulator. The results demonstrate that the proposed Scheduling-PROPHET can achieve better performances in several key aspects compared with the existing protocols.

Genome-Wide Survey of Invertase Encoding Genes and Functional Characterization of an Extracellular Fungal Pathogen-Responsive Invertase in Glycine max.

Invertases are essential enzymes that irreversibly catalyze the cleavage of sucrose into glucose and fructose. Cell wall invertase (CWI) and vacuolar invertase (VI) are glycosylated proteins and exert fundamental roles in plant growth as well as in response to environmental cues. As yet, comprehensive insight into invertase encoding genes are lacking in Glycine max. In the present study, the systematic survey of gene structures, coding regions, regulatory elements, conserved motifs, and phylogenies resulted in the identification of thirty⁻two putative invertase genes in soybean genome. Concomitantly, impacts on gene expression, enzyme activities, proteins, and soluble sugar accumulation were explored in specific tissues upon stress perturbation. In combination with the observation of subcellular compartmentation of the fluorescent fusion protein that indeed exported to apoplast, heterologous expression, and purification in using Pichia pastoris system revealed that GmCWI4 was a typical extracellular invertase. We postulated that GmCWI4 may play regulatory roles and be involved in pathogenic fungi defense. The experimental evaluation of physiological significance via phenotypic analysis of mutants under stress exposure has been initiated. Moreover, our paper provides theoretical basis for elucidating molecular mechanisms of invertase in association with inhibitors underlying the stress regime, and will contribute to the improvement of plant performance to a diverse range of stressors.

Structure of the Legionella Virulence Factor, SidC Reveals a Unique PI(4)P-Specific Binding Domain Essential for Its Targeting to the Bacterial Phagosome.

The opportunistic intracellular pathogen Legionella pneumophila is the causative agent of Legionnaires' disease. L. pneumophila delivers nearly 300 effector proteins into host cells for the establishment of a replication-permissive compartment known as the Legionella-containing vacuole (LCV). SidC and its paralog SdcA are two effectors that have been shown to anchor on the LCV via binding to phosphatidylinositol-4-phosphate [PI(4)P] to facilitate the recruitment of ER proteins to the LCV. We recently reported that the N-terminal SNL (SidC N-terminal E3 Ligase) domain of SidC is a ubiquitin E3 ligase, and its activity is required for the recruitment of ER proteins to the LCV. Here we report the crystal structure of SidC (1-871). The structure reveals that SidC contains four domains that are packed into an arch-like shape. The P4C domain (PI(4)P binding of SidC) comprises a four α-helix bundle and covers the ubiquitin ligase catalytic site of the SNL domain. Strikingly, a pocket with characteristic positive electrostatic potentials is formed at one end of this bundle. Liposome binding assays of the P4C domain further identified the determinants of phosphoinositide recognition and membrane interaction. Interestingly, we also found that binding with PI(4)P stimulates the E3 ligase activity, presumably due to a conformational switch induced by PI(4)P from a closed form to an open active form. Mutations of key residues involved in PI(4)P binding significantly reduced the association of SidC with the LCV and abolished its activity in the recruitment of ER proteins and ubiquitin signals, highlighting that PI(4)P-mediated targeting of SidC is critical to its function in the remodeling of the bacterial phagosome membrane. Finally, a GFP-fusion with the P4C domain was demonstrated to be specifically localized to PI(4)P-enriched compartments in mammalian cells. This domain shows the potential to be developed into a sensitive and accurate PI(4)P probe in living cells.

The Legionella effector SidC defines a unique family of ubiquitin ligases important for bacterial phagosomal remodeling.

The activity of proteins delivered into host cells by the Dot/Icm injection apparatus allows Legionella pneumophila to establish a niche called the Legionella-containing vacuole (LCV), which is permissive for intracellular bacterial propagation. Among these proteins, substrate of Icm/Dot transporter (SidC) anchors to the cytoplasmic surface of the LCV and is important for the recruitment of host endoplasmic reticulum (ER) proteins to this organelle. However, the biochemical function underlying this activity is unknown. Here, we determined the structure of the N-terminal domain of SidC, which has no structural homology to any protein. Sequence homology analysis revealed a potential canonical catalytic triad formed by Cys46, His444, and Asp446 on the surface of SidC. Unexpectedly, we found that SidC is an E3 ubiquitin ligase that uses the C-H-D triad to catalyze the formation of high-molecular-weight polyubiquitin chains through multiple ubiquitin lysine residues. A C46A mutation completely abolished the E3 ligase activity and the ability of the protein to recruit host ER proteins as well as polyubiquitin conjugates to the LCV. Thus, SidC represents a unique E3 ubiquitin ligase family important for phagosomal membrane remodeling by L. pneumophila.

The structure of phosphoinositide phosphatases: Insights into substrate specificity and catalysis.

Phosphoinositides (PIs) are a group of key signaling and structural lipid molecules involved in a myriad of cellular processes. PI phosphatases, together with PI kinases, are responsible for the conversion of PIs between distinctive phosphorylation states. PI phosphatases are a large collection of enzymes that are evolved from at least two disparate ancestors. One group is distantly related to endonucleases, which apply divalent metal ions for phosphoryl transfer. The other group is related to protein tyrosine phosphatases, which contain a highly conserved active site motif Cys-X5-Arg (CX5R). In this review, we focus on structural insights to illustrate current understandings of the molecular mechanisms of each PI phosphatase family, with emphasis on their structural basis for substrate specificity determinants and catalytic mechanisms. This article is part of a Special Issue entitled Phosphoinositides.

Exploiting the ubiquitin and phosphoinositide pathways by the Legionella pneumophila effector, SidC.

Intracellular bacterial pathogens use secreted effector proteins to alter host cellular processes, with the goal of subverting host defenses and allowing the infection to progress. One such pathogen, Legionella pneumophila, secretes ~300 proteins into its host to alter a number of pathways including intracellular trafficking, phosphoinositide metabolism, and cell signaling. The Legionella effector SidC was previously found to bind to PI(4)P and was responsible for the enrichment of ER proteins and ubiquitinated species on the Legionella-containing vacuoles. Through our recent work, we have discovered that SidC contains a unique N-terminal E3 ubiquitin ligase domain and a C-terminal novel PI(4)P-binding domain. Our results demonstrate that SidC serves to link two distinct cellular pathways, ubiquitin and phosphoinositide. However, how the ubiquitin ligase activity regulates host membrane trafficking events remains to be investigated.

Structural basis for substrate recognition by a unique Legionella phosphoinositide phosphatase.

Legionella pneumophila is an opportunistic intracellular pathogen that causes sporadic and epidemic cases of Legionnaires' disease. Emerging data suggest that Legionella infection involves the subversion of host phosphoinositide (PI) metabolism. However, how this bacterium actively manipulates PI lipids to benefit its infection is still an enigma. Here, we report that the L. pneumophila virulence factor SidF is a phosphatidylinositol polyphosphate 3-phosphatase that specifically hydrolyzes the D3 phosphate of PI(3,4)P(2) and PI(3,4,5)P(3). This activity is necessary for anchoring of PI(4)P-binding effectors to bacterial phagosomes. Crystal structures of SidF and its complex with its substrate PI(3,4)P(2) reveal striking conformational rearrangement of residues at the catalytic site to form a cationic pocket that specifically accommodates the D4 phosphate group of the substrate. Thus, our findings unveil a unique Legionella PI phosphatase essential for the establishment of lipid identity of bacterial phagosomes.

Crystal structure of Legionella pneumophila dephospho-CoA kinase reveals a non-canonical conformation of P-loop.

Dephospho-CoA kinase (DPCK; EC 2.7.1.24) catalyzes the final step in the coenzyme A biosynthetic pathway. DPCK transfers a phosphate group from ATP to the 3-hydroxyl group of the ribose of dephosphocoenzyme A (dCoA) to yield CoA and ADP. Upon the binding of ligands, large conformational changes is induced in DPCKs, as well as in many other kinases, to shield the bound ATP in their catalytic site from the futile hydrolysis by bulk water molecules. To investigate the molecular mechanisms underlying the phosphoryl transfer during DPCK catalytic cycle, we determined the crystal structures of the Legionellapneumophila DPCK (LpDPCK) both in its apo-form and in complex with ATP. The structures reveal that LpDPCK comprises of three domains, the classical core domain, the CoA domain, and the LID domain, which are packed together to create a central cavity for substrate-binding and enzymatic catalysis. The binding of ATP induces large conformational changes, including a hinge-bending motion of the CoA binding domain and the "helix to loop" conformational change of the P-loop. Finally, modeling of a dCoA molecule to the enzyme provides insights into the catalytic mechanism of DPCK.

Identification and structural characterization of a Legionella phosphoinositide phosphatase.

Bacterial pathogen Legionella pneumophila is the causative agent of Legionnaires' disease, which is associated with intracellular replication of the bacteria in macrophages of human innate immune system. Recent studies indicate that pathogenic bacteria can subvert host cell phosphoinositide (PI) metabolism by translocated virulence effectors. However, in which manner Legionella actively exploits PI lipids to benefit its infection is not well characterized. Here we report that L. pneumophila encodes an effector protein, named SidP, that functions as a PI-3-phosphatase specifically hydrolyzing PI(3)P and PI(3,5)P2 in vitro. This activity of SidP rescues the growth phenotype of a yeast strain defective in PI(3)P phosphatase activity. Crystal structure of SidP orthologue from Legionella longbeachae reveals that this unique PI-3-phosphatase is composed of three distinct domains: a large catalytic domain, an appendage domain that is inserted into the N-terminal portion of the catalytic domain, and a C-terminal α-helical domain. SidP has a small catalytic pocket that presumably provides substrate specificity by limiting the accessibility of bulky PIs with multiple phosphate groups. Together, our identification of a unique family of Legionella PI phosphatases highlights a common scheme of exploiting host PI lipids in many intracellular bacterial pathogen infections.

Crystal structure of the yeast Sac1: implications for its phosphoinositide phosphatase function.

Sac family phosphoinositide (PI) phosphatases are an essential family of CX(5)R(T/S)-based enzymes, involved in numerous aspects of cellular function such as PI homeostasis, cellular signalling, and membrane trafficking. Genetic deletions of several Sac family members result in lethality in animal models and mutations of the Sac3 gene have been found in human hereditary diseases. In this study, we report the crystal structure of a founding member of this family, the Sac phosphatase domain of yeast Sac1. The 2.0 A resolution structure shows that the Sac domain comprises of two closely packed sub-domains, a novel N-terminal sub-domain and the PI phosphatase catalytic sub-domain. The structure further shows a striking conformation of the catalytic P-loop and a large positively charged groove at the catalytic site. These findings suggest an unusual mechanism for its dephosphorylation function. Homology structural modeling of human Fig4/Sac3 allows the mapping of several disease-related mutations and provides a framework for the understanding of the molecular mechanisms of human diseases.

Induction of caspase 3 activation by multiple Legionella pneumophila Dot/Icm substrates.

The intracellular pathogen Legionella pneumophila is able to strike a balance between the death and survival of the host cell during infection. Despite the presence of high level of active caspase 3, the executioner caspase of apoptotic cell death, infected permissive macrophages are markedly resistant to exogenous apoptotic stimuli. Several bacterial molecules capable of promoting the cell survival pathways have been identified, but proteins involved in the activation of caspase 3 remain unknown. To study the mechanism of L. pneumophila-mediated caspase 3 activation, we tested all known Dot/Icm substrates for their ability to activate caspase 3. Five effectors capable of causing caspase 3 activation upon transient expression were identified. Among these, by using its ability to activate caspase 3 by inducing the release of cytochrome c from the mitochondria, we demonstrated that VipD is a phospholipase A2, which hydrolyses phosphatidylethanolamine (PE) and phosphocholine (PC) on the mitochondrial membrane in a manner that appears to require host cofactor(s). The lipase activity leads to the production of free fatty acids and 2-lysophospholipids, which destabilize the mitochondrial membrane and may contribute to the release of cytochrome c and the subsequent caspase 3 activation. Furthermore, we found that whereas it is not detectably defectively in caspase 3 activation in permissive cells, amutant lacking all of these five genes is less potent in inducing apoptosis in dendritic cells. Our results reveal that activation of host cell death pathways by L. pneumophila is a result of the effects of multiple bacterial proteins with diverse biochemical functions.

Orthogonal experimental study on the compressibility characteristics of bank sandy silt based on freeze-thaw effects.

The compressibility of bank soils is a critical consideration in t riverbank protection project, construction. In the Inner Mongolia section of the Yellow River, a seasonal frozen soil region, the impact of F-T cycles on soil compressibility cannot be overlooked. This study, based on F-T cycle tests, conducted orthogonal consolidation tests on embankment sandy silt from the Inner Mongolia section of the Yellow River, considering varying initial w and ρd. It investigated the effects of different initial w, ρd, and F-T cycles on soil compressibility, ranked and assessed the significance of influencing factors, and established a predictive model for the compressibility of Inner Mongolia section Yellow River embankment sandy silt. The results show that: the embankment sandy silt is medium-high compression soil, with a between 0.1 and 0.74 MPa-1, Es between 2.65 and 18.47 MPa, and Cc between 0.04 and 0.24 MPa. The greater the ρd of soil, the smaller the initial w, the smaller the a and Cc, and the greater the Es of soil. The F-T effect affects soil compressibility, and soil a, Es and Cc are linearly related to the number of F-T cycles. The ranking of factors influencing soil compressibility is ρd > w > F-T cycles. The initial ρd and w are decisive factors affecting soil compressibility, while the impact of F-T cycles is relatively minor. Additionally, a regression predictive model based on the initial ρd and w of the soil demonstrates good performance in predicting soil compression indices. This model can be utilized for predicting the compressibility indices of embankment soil in the Inner Mongolia section of the Yellow River.

Dynamic analysis of predictive biomarkers for radiation therapy efficacy in non-small cell lung cancer patients by next-generation sequencing based on blood specimens.

PURPOSE: Radiotherapy plays an important role in the treatment of non-small cell lung cancer, and the aim of this study was to explore the potential association of single gene mutation or pathway mutations with radiotherapy response using targeted next-generation sequencing (NGS) testing of peripheral blood specimens. MATERIAL AND METHODS: We performed NGS containing 425 genes on peripheral blood specimens from 13 NSCLC patients pre- and post-radiotherapy or post-radiotherapy. Patients whose tumors were in complete response or partial response within 1 month after radiotherapy were classified as a radiotherapy-sensitive group; otherwise, they were categorized as a radiotherapy-resistant group. The relationship between single gene mutations, signaling pathway mutations, dynamic fluctuations in circulating tumor DNA （ctDNA）, and radiotherapy response was investigated. RESULTS: Of these 13 patients，6 patients were categorized as a radiotherapy-sensitive group (46.2%), and 7 patients were categorized as a radiotherapy-resistant group (53.8%). No correlation between single gene mutations and response to radiotherapy. Mutations in the SWI/SNF complex were more likely to occur in the radiotherapy-sensitive group than in the other group (p = 0.07). Among all patients，9 patients underwent NGS tests pre- and post-radiotherapy. Dynamic analysis based on ctDNA before and after treatment revealed that a decrease in ctDNA abundance was observed in all patients in the radiotherapy-sensitive group. CONCLUSIONS: SWI/SNF complex mutations may be potential predictive biomarkers of radiotherapy response. Decreased ctDNA abundance after radiotherapy correlates with better efficacy of radiotherapy.