Novel cow dung-doped sludge biochar as an efficient ozone catalyst: Synergy between graphitic structure and defects induces free radical pathways.

A composite material, cow dung-doped sludge biochar (Zn@SBC-CD), was synthesized by one-step pyrolysis using ZnCl2 as an activating agent and applied to a catalytic ozonation process (COP) for methylene blue (MB) removal. SEM, XRD, FTIR, XPS and BET analyses were performed to characterize the biochar (BC) catalysts. Zn@SBC-CD had high graphitization degree, abundant active sites and uniform distribution of Zn on its surface. Complete removal of MB was achieved within 10 min, with a removal rate much higher than that of ozone alone (32.4%), implying the excellent ozone activation performance of Zn@SBC-CD. The influence of experimental parameters on MB removal efficiency was examined. Under the optimum conditions in terms of ozone dose 0.04 mg/mL, catalyst dose 400 mg/L and pH 6.0, COD was completely removed after 20 min. Electron paramagnetic resonance (EPR) analysis revealed radical and non-radical pathways were involved in MB degradation. The Zn@SBC-CD/O3 system generated superoxide anion radicals (•O2-), which were the main active species for MB removal, through adsorption, transformation, and transfer, Furthermore, Zn@SBC-CD exhibited good reusability and stability in cycling experiments. This study provides a novel approach for the utilization of cow dung and sludge in synthesis of functional biocatalysts and application in organic wastewater treatment.

DBT is a metabolic switch for maintenance of proteostasis under proteasomal impairment.

Proteotoxic stress impairs cellular homeostasis and underlies the pathogenesis of many neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). The proteasomal and autophagic degradation of proteins are two major pathways for protein quality control in the cell. Here, we report a genome-wide CRISPR screen uncovering a major regulator of cytotoxicity resulting from the inhibition of the proteasome. Dihydrolipoamide branched chain transacylase E2 (DBT) was found to be a robust suppressor, the loss of which protects against proteasome inhibition-associated cell death through promoting clearance of ubiquitinated proteins. Loss of DBT altered the metabolic and energetic status of the cell and resulted in activation of autophagy in an AMP-activated protein kinase (AMPK)-dependent mechanism in the presence of proteasomal inhibition. Loss of DBT protected against proteotoxicity induced by ALS-linked mutant TDP-43 in Drosophila and mammalian neurons. DBT is upregulated in the tissues from ALS patients. These results demonstrate that DBT is a master switch in the metabolic control of protein quality control with implications in neurodegenerative diseases.

PLK1 inhibition dampens NLRP3 inflammasome-elicited response in inflammatory disease models.

Unabated activation of the NLR family pyrin domain-containing 3 (NLRP3) inflammasome is linked with the pathogenesis of various inflammatory disorders. Polo-like kinase 1 (PLK1) has been widely studied for its role in mitosis. Here, using both pharmacological and genetic approaches, we demonstrate that PLK1 promoted NLRP3 inflammasome activation at cell interphase. Using an unbiased proximity-dependent biotin identification (Bio-ID) screen for the PLK1 interactome in macrophages, we show an enhanced proximal association of NLRP3 with PLK1 upon NLRP3 inflammasome activation. We further confirmed the interaction between PLK1 and NLRP3 and identified the interacting domains. Mechanistically, we show that PLK1 orchestrated the microtubule-organizing center (MTOC) structure and NLRP3 subcellular positioning upon inflammasome activation. Treatment with a selective PLK1 kinase inhibitor suppressed IL-1ß production in in vivo inflammatory models, including LPS-induced endotoxemia and monosodium urate-induced peritonitis in mice. Our results uncover a role of PLK1 in regulating NLRP3 inflammasome activation during interphase and identify pharmacological inhibition of PLK1 as a potential therapeutic strategy for inflammatory diseases with excessive NLRP3 inflammasome activation.

Identifying risk factors for in-stent restenosis in symptomatic intracranial atherosclerotic stenosis: a systematic review and meta-analysis.

Background: In-stent restenosis (ISR) is an adverse and notable event in the treatment of intracranial atherosclerotic stenosis (ICAS) with percutaneous transluminal angioplasty and stenting (PTAS). The incidence and contributing factors have not been fully defined. This study was performed to evaluate factors associated with ISR after PTAS. Data source: We identified studies on ISR after PTAS from an electronic search of articles in PubMed, Ovid MEDLINE, and the Cochrane Central Database (dated up to July 2022). Results: A total of 19 studies, including 452 cases of ISR after 2,047 PTAS, were included in the meta-analysis. The pooled incidence rate of in-stent restenosis was 22.08%. ISR was more likely to occur in patients with coronary artery disease (OR = 1.686; 95% CI: 1.242-2.288; p = 0.0008), dissection (OR = 6.293; 95% CI: 3.883-10.197; p < 0.0001), and higher residual stenosis (WMD = 3.227; 95% CI: 0.142-6.311; p = 0.0404). Patients treated with Wingspan stents had a significantly higher ISR rate than those treated with Enterprise stents (29.78% vs. 14.83%; p < 0.0001). Conclusions: The present study provides the current estimates of the robust effects of some risk factors for in-stent restenosis in intracranial atherosclerotic stenosis. The Enterprise stent had advantages compared with the Wingspan stent for ISR. The significant risk factors for ISR were coronary artery disease, dissection, and high residual stenosis. Local anesthesia was a suspected factor associated with ISR.

Functional evaluation of intracranial atherosclerotic stenosis by pressure ratio measurements.

Background: Fractional flow reserve is widely used for the functional evaluation of coronary artery stenosis. Some studies have similarly used the translesional pressure ratio measurements for the functional evaluation of intracranial atherosclerotic stenosis. In this paper, we aimed to investigate the relationship between pressure ratio and cerebral tissue perfusion by MR perfusion imaging and provided a non-invasive method for evaluating the functional significance of intracranial atherosclerotic stenosis. Methods: A total of 18 consecutive patients with intracranial atherosclerotic stenosis patients including 19 stenotic vessels were recruited. The pressure was measured using a pressure guidewire, the pressure ratio before and after the endovascular intervention was calculated and compared with the severity of diameter stenosis and perfusion-derived MR (the time to maximum tissure residue function (Tmax)). Moreover, the DSA-derived pressure ratio was computed using a novel computational fluid dynamics-based model, termed CFD-PR, and was compared with the actual pressure ratio to assess its diagnostic accuracy. Results: The pressure ratio increased after percutaneous transluminal angioplasty or stenting, while the correlation between pressure ratio and diameter stenosis was not significant. The pressure ratio was negatively correlated with Tmax (r = -0.73, P < 0.01), and a 95% confidence interval for the cutoff value of pressure ratio = 0.67 (95% confidence interval: 0.58-0.76) was suggested. There was a good correlation (mean = 0.02, Spearman's correlation coefficient r = 0.908, P < 0.001) and agreement (limits of agreement: -0.157 to 0.196, P = 0.954) between CFD-PR and the actual pressure ratio. Conclusions: This exploratory study indicates the pressure ratio may correlate with the perfusion status. The pressure ratio can be calculated through a non-invasive method using a computational fluid dynamics-based method.

The predictive role of systemic inflammation response index in the prognosis of traumatic brain injury: A propensity score matching study.

Background: We aimed to evaluate the predictive power of systemic inflammation response index (SIRI), a novel biomarker, to predict all-cause mortality in patients with traumatic brain injury (TBI) in the intensive care unit (ICU). Methods: Clinical data were retrieved from the Medical Information Mart for Intensive Care-IV (MIMIC-IV) database. Kaplan-Meier (KM) methods and cox proportional hazard models were performed to examine the association between SIRI and all-cause mortality. The predictive power of SIRI was evaluated compared to other leukocyte-related indexes including neutrophils, lymphocytes, monocytes and white blood cells (WBC) by the Receiver Operating Characteristic (ROC)curve for 30-day mortality. In addition, propensity score matching (PSM) was conducted to reduce confounding. Results: A total of 350 TBI patients were enrolled overall in our study. The optimal cutoff point of SIRI was determined at 11.24 × 109/L. After 1:1 PSM, 66 matched pairs (132 patients) were generated. During the 30-day, in-hospital and 365-day follow-up periods, patients with low SIRI level were associated with improved survival (p < 0.05) compared with patients with high SIRI level. Cox regression analysis identified that higher SIRI values was an independent risk factor for all-cause mortality and results were stable on multiple subgroup analyses. Furthermore, ROC analysis indicated that the area under the curve of SIRI [0.6658 (95% Confidence Interval, 0.5630-0.7687)] was greater than that of neutrophils, monocytes, lymphocytes and WBC. The above results were also observed in the matched cohort. Conclusion: It was suggested that TBI patients with high SIRI level would suffer from a high risk of 30-day, in-hospital and 365-day mortality. SIRI is a promising inflammatory biomarker for predicting TBI patients' prognosis with relatively better predictive power than other single indicators related to peripheral differential leukocyte counts.

Regulatory T-Cell Response to Low-Dose Interleukin-2 in Ischemic Heart Disease.

Regulatory T-Cell Response to Low-Dose Interleukin-2 in Ischemic Heart Disease This phase 1b/2a, randomized, double-blind, placebo-controlled, dose-escalation trial tested low-dose subcutaneous aldesleukin (recombinant IL-2) in patients with ischemic heart disease. Low-dose IL-2 expanded Tregs, without adverse events of major concern. Single-cell RNA-sequencing of circulating immune cells was used to provide mechanistic assessment of the treatment's effects.

Innate Lymphoid Cells Promote Recovery of Ventricular Function After Myocardial Infarction.

BACKGROUND: Innate lymphoid cells type 2 (ILC2s) play critical homeostatic functions in peripheral tissues. ILC2s reside in perivascular niches and limit atherosclerosis development. OBJECTIVES: ILC2s also reside in the pericardium but their role in postischemic injury is unknown. METHODS: We examined the role of ILC2 in a mouse model of myocardial infarction (MI), and compared mice with or without genetic deletion of ILC2. We determined infarct size using histology and heart function using echocardiography. We assessed cardiac ILC2 using flow cytometry and RNA sequencing. Based on these data, we devised a therapeutic strategy to activate ILC2 in mice with acute MI, using exogenous interleukin (IL)-2. We also assessed the ability of low-dose IL-2 to activate ILC2 in a double-blind randomized clinical trial of patients with acute coronary syndromes (ACS). RESULTS: We found that ILC2 levels were increased in pericardial adipose tissue after experimental MI, and genetic ablation of ILC2 impeded the recovery of heart function. RNA sequencing revealed distinct transcript signatures in ILC2, and pointed to IL-2 axis as a major upstream regulator. Treatment of T-cell-deficient mice with IL-2 (to activate ILC2) significantly improved the recovery of heart function post-MI. Administration of low-dose IL-2 to patients with ACS led to activation of circulating ILC2, with significant increase in circulating IL-5, a prototypic ILC2-derived cytokine. CONCLUSIONS: ILC2s promote cardiac healing and improve the recovery of heart function after MI in mice. Activation of ILC2 using low-dose IL-2 could be a novel therapeutic strategy to promote a reparative response after MI.

A Helicase Unwinds Hexanucleotide Repeat RNA G-Quadruplexes and Facilitates Repeat-Associated Non-AUG Translation.

The expansion of a hexanucleotide repeat GGGGCC (G4C2) in the C9orf72 gene is the most common cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The G4C2 expansion leads to repeat-associated non-AUG (RAN) translation and the production of toxic dipeptide repeat (DPR) proteins, but the mechanisms of RAN translation remain enigmatic. Here, we report that the RNA helicase DHX36 is a robust positive regulator of C9orf72 RAN translation. DHX36 has a high affinity for the G4C2 repeat RNA, preferentially binds to the repeat RNA's G-quadruplex conformation, and efficiently unwinds the G4C2 G-quadruplex structures. Native DHX36 interacts with the G4C2 repeat RNA and is essential for effective RAN translation in the cell. In induced pluripotent stem cells and differentiated motor neurons derived from C9orf72-linked ALS patients, reducing DHX36 significantly decreased the levels of endogenous DPR proteins. DHX36 is also aberrantly upregulated in tissues of C9orf72-linked ALS patients. These results indicate that DHX36 facilitates C9orf72 RAN translation by resolving repeat RNA G-quadruplex structures and may be a potential target for therapeutic intervention.

MARK2 phosphorylates eIF2α in response to proteotoxic stress.

The regulation of protein synthesis is essential for maintaining cellular homeostasis, especially during stress responses, and its dysregulation could underlie the development of human diseases. The critical step during translation regulation is the phosphorylation of eukaryotic initiation factor 2 alpha (eIF2α). Here we report the identification of a direct kinase of eIF2α, microtubule affinity-regulating kinase 2 (MARK2), which phosphorylates eIF2α in response to proteotoxic stress. The activity of MARK2 was confirmed in the cells lacking the 4 previously known eIF2α kinases. MARK2 itself was found to be a substrate of protein kinase C delta (PKCδ), which serves as a sensor for protein misfolding stress through a dynamic interaction with heat shock protein 90 (HSP90). Both MARK2 and PKCδ are activated via phosphorylation in proteotoxicity-associated neurodegenerative mouse models and in human patients with amyotrophic lateral sclerosis (ALS). These results reveal a PKCδ-MARK2-eIF2α cascade that may play a critical role in cellular proteotoxic stress responses and human diseases.

USP7 regulates ALS-associated proteotoxicity and quality control through the NEDD4L-SMAD pathway.

An imbalance in cellular homeostasis occurring as a result of protein misfolding and aggregation contributes to the pathogeneses of neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). Here, we report the identification of a ubiquitin-specific protease, USP7, as a regulatory switch in a protein quality-control system that defends against proteotoxicity. A genome-wide screen in a Caenorhabditis elegans model of SOD1-linked ALS identified the USP7 ortholog as a suppressor of proteotoxicity in the nervous system. The actions of USP7 orthologs on misfolded proteins were found to be conserved in Drosophila and mammalian cells. USP7 acts on protein quality control through the SMAD2 transcription modulator of the transforming growth factor ß pathway, which activates autophagy and enhances the clearance of misfolded proteins. USP7 deubiquitinates the E3 ubiquitin ligase NEDD4L, which mediates the degradation of SMAD2. Inhibition of USP7 protected against proteotoxicity in mammalian neurons, and SMAD2 was found to be dysregulated in the nervous systems of ALS patients. These findings reveal a regulatory pathway of protein quality control that is implicated in the proteotoxicity-associated neurodegenerative diseases.

Interleukin-33 Signaling Controls the Development of Iron-Recycling Macrophages.

Splenic red pulp macrophages (RPMs) contribute to erythrocyte homeostasis and are required for iron recycling. Heme induces the expression of SPIC transcription factor in monocyte-derived macrophages and promotes their differentiation into RPM precursors, pre-RPMs. However, the requirements for differentiation into mature RPMs remain unknown. Here, we have demonstrated that interleukin (IL)-33 associated with erythrocytes and co-cooperated with heme to promote the generation of mature RPMs through activation of the MyD88 adaptor protein and ERK1/2 kinases downstream of the IL-33 receptor, IL1RL1. IL-33- and IL1RL1-deficient mice showed defective iron recycling and increased splenic iron deposition. Gene expression and chromatin accessibility studies revealed a role for GATA transcription factors downstream of IL-33 signaling during the development of pre-RPMs that retained full potential to differentiate into RPMs. Thus, IL-33 instructs the development of RPMs as a response to physiological erythrocyte damage with important implications to iron recycling and iron homeostasis.

The effects of dyslipidaemia and cholesterol modulation on erythrocyte susceptibility to malaria parasite infection.

BACKGROUND: Malaria disease commences when blood-stage parasites, called merozoites, invade human erythrocytes. Whilst the process of invasion is traditionally seen as being entirely merozoite-driven, emerging data suggests erythrocyte biophysical properties markedly influence invasion. Cholesterol is a major determinant of cell membrane biophysical properties demanding its interrogation as a potential mediator of resistance to merozoite invasion of the erythrocyte. METHODS: Biophysical measurements of erythrocyte deformability by flicker spectroscopy were used to assess changes in erythrocyte bending modulus on forced integration of cholesterol and how these artificial changes affect invasion by human Plasmodium falciparum merozoites. To validate these observations in a natural context, either murine Plasmodium berghei or human Plasmodium falciparum merozoites were tested for their ability to invade erythrocytes from a hypercholesterolaemic mouse model or human clinical erythrocyte samples deriving from patients with a range of serum cholesterol concentrations, respectively. RESULTS: Erythrocyte bending modulus (a measure of deformability) was shown to be markedly affected by artificial modulation of cholesterol content and negatively correlated with merozoite invasion efficiency. In an in vitro infection context, however, erythrocytes taken from hypercholesterolaemic mice or from human clinical samples with varying serum cholesterol levels showed little difference in their susceptibility to merozoite invasion. Explaining this, membrane cholesterol levels in both mouse and human hypercholesterolaemia erythrocytes were subsequently found to be no different from matched normal serum controls. CONCLUSIONS: Based on these observations, serum cholesterol does not appear to impact on erythrocyte susceptibility to merozoite entry. Indeed, no relationship between serum cholesterol and cholesterol content of the erythrocyte is apparent. This work, nonetheless, suggests that native polymorphisms which do affect membrane lipid composition would be expected to affect parasite entry. This supports investigation of erythrocyte biophysical properties in endemic settings, which may yet identify naturally protective lipid-related polymorphisms.

Impaired Autophagy in CD11b+ Dendritic Cells Expands CD4+ Regulatory T Cells and Limits Atherosclerosis in Mice.

RATIONALE: Atherosclerosis is a chronic inflammatory disease. Recent studies have shown that dysfunctional autophagy in endothelial cells, smooth muscle cells, and macrophages, plays a detrimental role during atherogenesis, leading to the suggestion that autophagy-stimulating approaches may provide benefit. OBJECTIVE: Dendritic cells (DCs) are at the crossroad of innate and adaptive immune responses and profoundly modulate the development of atherosclerosis. Intriguingly, the role of autophagy in DC function during atherosclerosis and how the autophagy process would impact disease development has not been addressed. METHODS AND RESULTS: Here, we show that the autophagic flux in atherosclerosis-susceptible Ldlr-/- (low-density lipoprotein receptor-deficient) mice is substantially higher in splenic and aortic DCs compared with macrophages and is further activated under hypercholesterolemic conditions. RNA sequencing and functional studies on selective cell populations reveal that disruption of autophagy through deletion of Atg16l1 differentially affects the biology and functions of DC subsets in Ldlr-/- mice under high-fat diet. Atg16l1 deficient CD11b+ DCs develop a TGF (transforming growth factor)-ß-dependent tolerogenic phenotype and promote the expansion of regulatory T cells, whereas no such effects are seen with Atg16l1 deficient CD8α+ DCs. Atg16l1 deletion in DCs (all CD11c-expressing cells) expands aortic regulatory T cells in vivo, limits the accumulation of T helper cells type 1, and reduces the development of atherosclerosis in Ldlr-/- mice. In contrast, no such effects are seen when Atg16l1 is deleted selectively in conventional CD8α+ DCs and CD103+ DCs. Total T-cell or selective regulatory T-cell depletion abrogates the atheroprotective effect of Atg16l1 deficient DCs. CONCLUSIONS: In contrast to its proatherogenic role in macrophages, autophagy disruption in DCs induces a counter-regulatory response that maintains immune homeostasis in Ldlr-/- mice under high-fat diet and limits atherogenesis. Selective modulation of autophagy in DCs could constitute an interesting therapeutic target in atherosclerosis.

Publisher Correction: L3MBTL1 regulates ALS/FTD-associated proteotoxicity and quality control.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

L3MBTL1 regulates ALS/FTD-associated proteotoxicity and quality control.

Misfolded protein toxicity and failure of protein quality control underlie neurodegenerative diseases including amyotrophic lateral sclerosis and frontotemporal dementia. Here, we identified Lethal(3)malignant brain tumor-like protein 1 (L3MBTL1) as a key regulator of protein quality control, the loss of which protected against the proteotoxicity of mutant Cu/Zn superoxide dismutase or C9orf72 dipeptide repeat proteins. L3MBTL1 acts by regulating p53-dependent quality control systems that degrade misfolded proteins. SET domain-containing protein 8, an L3MBTL1-associated p53-binding protein, also regulated clearance of misfolded proteins and was increased by proteotoxicity-associated stresses in mammalian cells. Both L3MBTL1 and SET domain-containing protein 8 were upregulated in the central nervous systems of mouse models of amyotrophic lateral sclerosis and human patients with amyotrophic lateral sclerosis/frontotemporal dementia. The role of L3MBTL1 in protein quality control is conserved from Caenorhabditis elegans to mammalian neurons. These results reveal a protein quality-control pathway that operates in both normal stress response and proteotoxicity-associated neurodegenerative diseases.

A C9orf72-CARM1 axis regulates lipid metabolism under glucose starvation-induced nutrient stress.

Cells undergo metabolic adaptation during environmental changes by using evolutionarily conserved stress response programs. This metabolic homeostasis is exquisitely regulated, and its imbalance could underlie human pathological conditions. We report here that C9orf72, which is linked to the most common forms of the neurodegenerative diseases amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), is a key regulator of lipid metabolism under stress. Loss of C9orf72 leads to an overactivation of starvation-induced lipid metabolism that is mediated by dysregulated autophagic digestion of lipids and increased de novo fatty acid synthesis. C9orf72 acts by promoting the lysosomal degradation of coactivator-associated arginine methyltransferase 1 (CARM1), which in turn regulates autophagy-lysosomal functions and lipid metabolism. In ALS/FTD patient-derived neurons or tissues, a reduction in C9orf72 function is associated with dysregulation in the levels of CARM1, fatty acids, and NADPH oxidase NOX2. These results reveal a C9orf72-CARM1 axis in the control of stress-induced lipid metabolism and implicates epigenetic dysregulation in relevant human diseases.

LFA-1 activates focal adhesion kinases FAK1/PYK2 to generate LAT-GRB2-SKAP1 complexes that terminate T-cell conjugate formation.

Lymphocyte function-associated antigen 1 (LFA-1) affinity and avidity changes have been assumed to mediate adhesion to intercellular adhesion molecule-1 for T-cell conjugation to dendritic cells (DC). Although the T-cell receptor (TCR) and LFA-1 can generate intracellular signals, the immune cell adaptor protein linker for the activation of T cells (LAT) couples the TCR to downstream events. Here, we show that LFA-1 can mediate both adhesion and de-adhesion, dependent on receptor clustering. Although increased affinity mediates adhesion, LFA-1 cross-linking induced the association and activation of the protein-tyrosine kinases FAK1/PYK1 that phosphorylated LAT selectively on a single Y-171 site for the binding to adaptor complex GRB-2-SKAP1. LAT-GRB2-SKAP1 complexes were distinct from canonical LAT-GADs-SLP-76 complexes. LFA-1 cross-linking increased the presence of LAT-GRB2-SKAP1 complexes relative to LAT-GADs-SLP-76 complexes. LFA-1-FAK1 decreased T-cell-dendritic cell (DC) dwell times dependent on LAT-Y171, leading to reduced DO11.10 T cell binding to DCs and proliferation to OVA peptide. Overall, our findings outline a new model for LFA-1 in which the integrin can mediate both adhesion and de-adhesion events dependent on receptor cross-linking.

Marginal zone B cells control the response of follicular helper T cells to a high-cholesterol diet.

Splenic marginal zone B (MZB) cells, positioned at the interface between circulating blood and lymphoid tissue, detect and respond to blood-borne antigens. Here we show that MZB cells in mice activate a homeostatic program in response to a high-cholesterol diet (HCD) and regulate both the differentiation and accumulation of T follicular helper (TFH) cells. Feeding mice an HCD resulted in upregulated MZB cell surface expression of the immunoregulatory ligand PDL1 in an ATF3-dependent manner and increased the interaction between MZB cells and pre-TFH cells, leading to PDL1-mediated suppression of TFH cell motility, alteration of TFH cell differentiation, reduced TFH abundance and suppression of the proatherogenic TFH response. Our findings reveal a previously unsuspected role for MZB cells in controlling the TFH-germinal center response to a cholesterol-rich diet and uncover a PDL1-dependent mechanism through which MZB cells use their innate immune properties to limit an exaggerated adaptive immune response.

Non-cleavable talin rescues defect in the T-cell conjugation of T-cells deficient in the immune adaptor SKAP1.

While the cytoskeletal protein talin binds to the ß-chain of LFA-1, the immune cell adaptor SKAP1 (SKAP-55) binds to the α-chain of the same integrin via RapL. Whereas calpain protease cleavage of talin is important for LFA-1 activation, it has been unclear whether SKAP1 can alter the function of talin or its associated adaptor RIAM in T-cells. In this paper, we report that Skap1-/- T-cells showed a reduction in the translocation of talin and RIAM to the contact interface of T-cells with antigenic beads or dendritic cells (DCs) presenting OVA peptide to OT-1 T-cells. In addition, Skap1-/- T-cells show an altered pattern of talin cleavage, while the expression of a cleavage resistant form of talin (L432G) restored the impaired adhesion of OT1 transgenic Skap1-/- T-cells with DCs. SKAP1 therefore can affect the function of talin in T-cells needed for optimal T-cell/DC conjugation.