A20 is a negative regulator of BCL10- and CARMA3-mediated activation of NF-κB

The molecular complex containing CARMA proteins, BCL10 and TRAF6 has been identified recently as a key component in the signal transduction pathways that regulate activation of the nuclear factor κB (NF-κB) transcription factor. Here, we report that the inducible protein A20 negatively regulates these signaling cascades by means of its deubiquitylation activity. We show that A20 perturbs assembly of the complex containing CARMA3, BCL10 and IKKγ/NEMO, thereby suppressing activation of NF-κB. Together, our results further define the molecular mechanisms that control activation of NF-κB and reveal a function for A20 in the regulation of CARMA and BCL10 activity in lymphoid and non-lymphoid cells

Physical and Functional Interaction of CARMA1 and CARMA3 with Iκ Kinase γ-NFκB Essential Modulator

CARMA proteins are scaffold molecules that contain a caspase recruitment domain and a membrane-associated guanylate kinase-like domain. CARMA1 plays a critical role in mediating activation of the NFkappaB transcription factor following antigen receptor stimulation of both B and T lymphocytes. However, the biochemical mechanism by which CARMA1 regulates activation of NFkappaB remains to be determined. Here we have shown that CARMA1 and CARMA3 physically associate with Ikappa kinase gamma/NFkappaB essential modulator (IkappaKgamma-NEMO) in lymphoid and non-lymphoid cells. CARMA1 participates to an inducible large molecular complex that contains IkappaKgamma/NEMO, Bcl10, and IkappaKalpha/beta kinases. Expression of the NEMO-binding region of CARMA3 exerts a dominant negative effect on Bcl10-mediated activation of NFkappaB. Thus, our results provide direct evidence for physical and functional interaction between CARMA and the IkappaK complex and offer a biochemical framework to understand the molecular activities controlled by CARMA-1, -2, and -3 and Bcl10

CARMA2sh and ULK2 control pathogen-associated molecular patterns recognition in human keratinocytes: psoriasis-linked CARMA2sh mutants escape ULK2 censorship

The molecular complexes formed by specific members of the family of CARMA proteins, the CARD domain-containing adapter molecule BCL10 and MALT1 (CBM complex) represent a central hub in regulating activation of the pleiotropic transcription factor NF-κB. Recently, missense mutations in CARMA2sh have been shown to cause psoriasis in a dominant manner and with high penetrancy. Here, we demonstrate that in human keratinocytes CARMA2sh plays an essential role in the signal transduction pathway that connects pathogen-associated molecular patterns recognition to NF-κB activation. We also find that the serine/threonine kinase ULK2 binds to and phosphorylates CARMA2sh, thereby inhibiting its capacity to activate NF-κB by promoting lysosomal degradation of BCL10, which is essential for CARMA2sh-mediated NF-κB signaling. Remarkably, CARMA2sh mutants associated with psoriasis escape ULK2 inhibition. Finally, we show that a peptide blocking CARD-mediated BCL10 interactions reduces the capacity of psoriasis-linked CARMA2sh mutants to activate NF-κB. Our work elucidates a fundamental signaling mechanism operating in human keratinocytes and opens to novel potential tools for the therapeutical treatment of human skin disorders.This publication was made possible by a NPRP award (NPRP 7-1189-3-304) from the Qatar National Research Fund (a member of The Qatar Foundation)

The E3 Ubiquitin Ligase RNF7 Negatively Regulates CARD14/CARMA2sh Signaling

The three CARD-containing MAGUK (CARMA) proteins function as scaffolding molecules that regulate activation of the pro-inflammatory transcription factor NF-κB. Recently, mutations in CARMA2 have been linked to psoriasis susceptibility due to their acquired altered capacity to activate NF-κB. By means of two-hybrid screening with yeast, we identified RING finger protein 7 (RNF7) as an interactor of CARMA2. We present evidence that RNF7 functions as a negative regulator of the NF-κB-activating capacity of CARMA2. Mechanistically, RNF7 influences CARMA2 signaling by regulating the ubiquitination state of MALT1 and the NF-κB-regulatory molecule NEMO. Interestingly, CARMA2short (CARMA2sh) mutants associated with psoriasis susceptibility escape the negative control exerted by RNF7. In conclusion, our findings identify a new mechanism through which the ability of CARMA2 to activate NF-κB is regulated, which could have significant implications for our understanding of why mutations of this protein trigger human psoriasis

Evaluation of FAST COVID-19 SARS-CoV-2 Antigen Rapid Test Kit for Detection of SARS-CoV-2 in Respiratory Samples from Mildly Symptomatic or Asymptomatic Patients

Molecular tests are the gold standard to diagnose severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection but are associated with a diagnostic delay, while antigen detection tests can generate results within 20 min even outside a laboratory. In order to evaluate the accuracy and reliability of the FAST COVID-19 SARS-CoV-2 Antigen Rapid Test Kit (Ag-RDT), two respiratory swabs were collected simultaneously from 501 patients, with mild or no coronavirus disease 2019 (COVID-19)-related symptoms, and analyzed with both the Reverse Transcriptase-quantitative Polymerase Chain Reaction (RT-qPCR) and the FAST COVID-19 SARS-CoV-2 Antigen Rapid Test. Results were then compared to determine clinical performance in a screening setting. We measured a precision of 97.41% (95% CI 92.42–99.15%) and a recall of 98.26% (95% CI 93.88–99.25%), with a specificity of 99.22% (95% CI 97.74–99.74%), a negative predictive value of 99.48% (95% CI 97.98–99.87%), and an overall accuracy of 99.00% (95% CI 97.69–99.68%). Concordance was described by a Kappa coefficient of 0.971 (95% CI 0.947–0.996). Considering short lead times, low cost, and opportunities for decentralized testing, the Ag-RDT test can enhance the efforts to control SARS-CoV-2 spread in several settings

TRAF6-mediated ubiquitination of NEMO requires p62/sequestosome-1

The atypical protein kinase C-interacting protein p62/sequestosome-1 (p62) has emerged as a crucial molecule in a variety of cellular functions due to its involvement in various signaling mechanisms. p62 has been implicated in the activation of NF-?B in TNF?-stimulated cells and has been shown to be activated in response to interleukin-1? (IL-1?). Here we demonstrate that p62 interacts with NEMO, the regulatory subunit of the complex responsible for activation of NF-?B transcription factor. Depletion of p62 obtained through a short interfering RNA targeting p62 mRNA abrogated TRAF6 capacity to promote NEMO ubiquitination and severely impairs NF-?B activation following IL-1? stimulation.Together, these results indicate that p62 is an important intermediary in the NF-?B activation pathways implemented through non-degradative ubiquitination events.Telethon Grant GGP08125BScopu

A Peptide-Based Assay Discriminates Individual Antibody Response to the COVID-19 Pfizer/BioNTech mRNA Vaccine

The coronavirus disease 2019 (COVID-19) mRNA vaccine developed by Pfizer/BioNTech has been shown to be capable of developing an excellent antibody response against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein, with good production of neutralizing antibodies. Herein, we analyzed differences in the antibody response elicited by inoculation of the Pfizer/BioNTech vaccine through a peptide-based enzyme-linked immunosorbent assay (ELISA) that utilizes synthetic peptides derived from the spike protein in the immuno-adsorbent phase. Immunoreactivity against synthetic peptides was measured at different time points from vaccination and was also correlated with the SARS-CoV-2 neutralizing capacity. Our results indicate that all vaccinated subjects except one show reactive antibodies to at least one peptide at both 30 and 60 days after injection of the first dose. Only one of the 19 analyzed subjects showed no antibody response toward any of the selected peptides, consistently with a lower neutralizing capacity. More importantly, our data showed that the antibody response elicited by inoculation of the two doses of the Pfizer vaccine appears to be qualitatively individual, both in the type of recognized peptides and in the temporal persistence of the antibody response. Together with previous published data, our findings suggest that for effective pandemic control, it is important to constantly monitor the antibody protection in the population, and the assay described here could be a valid tool for this purpose

A peptide-based assay discriminates individual antibody response to SARS-CoV-2

SARS-CoV-2 virus is responsible for the current worldwide coronavirus disease 2019 (COVID-19) pandemic, infecting millions of people and causing hundreds of thousands of deaths. Understanding the antibody response to SARS-CoV-2 is crucial for the development of vaccines, therapeutics and public health interventions. However, lack of consistency in methods used to monitor antibody response to SARS-CoV-2 leaves some uncertainty in our fine understanding of the human antibody response mounted following SARS-CoV-2 infection. We developed a peptide-based enzyme-linked immunosorbent assay (ELISA) by selecting 7 synthetic peptides from the spike, membrane, and nucleocapsid protein sequences of SARS-CoV-2, which effectively detects the antibody response mounted by all COVID-19 convalescent tested. Strikingly, the assay shows a profound difference in antibody response among individual subjects, which may have a significant impact on disease severity. Together, our results define an efficient and specific serological assay to consistently measure the antibody response following SARS-CoV-2 infection, as well as help the design of vaccine and therapeuticals for prevention and treatment of COVID-19