Project description:Even though SYK and ZAP70 kinases share high sequence homology and serve analogous functions, their expression in B and T cells is strictly segregated throughout evolution. Here, we identified aberrant ZAP70 expression as a common feature in a broad range of B cell malignancies. We validated SYK as the kinase that sets the thresholds for negative selection of autoreactive and premalignant clones. When aberrantly expressed in B cells, ZAP70 competes with SYK at the BCR signalosome and redirects SYK from negative selection to tonic PI3K signaling, thereby promoting B cell survival. In genetic mouse models for B-ALL and B-CLL, conditional expression of Zap70 accelerated disease onset, while genetic deletion impaired malignant transformation. Inducible activation of Zap70 during B cell development compromised negative selection of autoreactive B cells, resulting in pervasive autoantibody production. Strict segregation of the two kinases is critical for normal B cell selection and represents a central safeguard against the development of autoimmune disease and B cell malignancies.
Project description:Effective methods for predicting COVID-19 disease trajectories are urgently needed. Here, enzyme-linked immunosorbent assay (ELISA) and coronavirus antigen microarray (COVAM) analysis mapped antibody epitopes in the plasma of COVID-19 patients (n = 86) experiencing a wide range of disease states. The experiments identified antibodies to a 21-residue epitope from nucleocapsid (termed Ep9) associated with severe disease, including admission to the intensive care unit (ICU), requirement for ventilators, or death. Importantly, anti-Ep9 antibodies can be detected within 6 days post-symptom onset and sometimes within 1 day. Furthermore, anti-Ep9 antibodies correlate with various comorbidities and hallmarks of immune hyperactivity. We introduce a simple-to-calculate, disease risk factor score to quantitate each patient’s comorbidities and age. For patients with anti-Ep9 antibodies, scores above 3.0 predict more severe disease outcomes with a 13.42 likelihood ratio (96.7% specificity). The results lay the groundwork for a new type of COVID-19 prognostic to allow early identification and triage of high-risk patients. Such information could guide more effective therapeutic intervention.
Project description:Plasma protein expression patterns can be used as prognostic biomarkers in various types of cancer. We aimed to identify a protein-based signature for distant metastatic risk assessment in patients with locoregionally advanced nasopharyngeal carcinoma (LA-NPC).
Project description:Abstract: O-GlcNAc is an abundant post-translational modification found on nuclear and cytoplasmic proteins in all metazoans. This modification regulates a wide variety of cellular processes, and elevated O-GlcNAc levels have been implicated in cancer progression. A single essential enzyme, O-GlcNAc transferase (OGT), is responsible for all nucleocytoplasmic O-GlcNAcylation. Understanding how this enzyme chooses its substrates is critical for understanding, and potentially manipulating, its functions. Here we use protein microarray technology and proteome-wide glycosylation profiling to show that conserved aspartate residues in the tetratricopeptide repeat (TPR) lumen of OGT drive substrate selection. Changing these residues to alanines alters substrate selectivity and unexpectedly increases rates of protein glycosylation. Our findings support a model where sites of glycosylation for many OGT substrates are determined by TPR domain contacts to substrate side chains five to fifteen residues C-terminal to the glycosite. In addition to guiding design of inhibitors that target OGT's TPR domain, this information will inform efforts to engineer substrates to explore biological functions.
Project description:Investigation of whole genome-derived tiled peptide arrays to identify epitopes associated with autoantibody reactivity in NSCLC as a potential means for early detection. Arrays consisted of 2,781,902 tiled peptides representing 20,193 proteins encoded in the human genome. The detailed analysis in this study is further described in Yan et al. Whole genome-derived tiled peptide arrays detect pre-diagnostic autoantibody signatures in non-small cell lung cancer. Cancer Res. 2019 Feb 5. pii: canres.1536.2018
Project description:β-cell specific Mettl14 knock-out mice display reduced N6-methyladenosine (m6A) levels and recapitulate human Type II diabetes (T2D) islet phenotype with early diabetes onset and mortality secondary to decreased β-cell proliferation and insulin degranulation. To gain insights into the role of m6A in regulating the IGF1/insulin -> AKT - > PDX1 pathway and to dissect the signaling networks modulating AKT phosphorylation, we subjected freshly isolated islets from control and Mettl14 knock-out mice to phospho-antibody microarrays.
Project description:Abstract: The essential mammalian enzyme O-GlcNAc Transferase (OGT) is uniquely responsible for transferring N-acetylglucosamine to over a thousand nuclear and cytoplasmic proteins, yet there is no known consensus sequence and it remains unclear how OGT recognizes its substrates. To address this question, we have developed a protein microarray assay that chemoenzymatically labels de novo sites of glycosylation with biotin, allowing us to simultaneously as-sess OGT activity across >6000 human proteins. We used this assay to examine the contribution of a conserved asparagine ladder within the lumen of OGT’s superhelical tetratri-copeptide repeat (TPR) domain to substrate selection. When these residues were mutated, OGT retained full activity against short peptides, but showed low to no activity against most of the OGT substrates on the microarray. O-GlcNAcylation of protein substrates in cell extracts was also greatly attenuated. We conclude that OGT recognizes a majority of its substrates by binding them to the asparagine ladder in the TPR lumen proximal to the catalytic domain. This series contains microarray data both comparing the new chemoenzymatic method to antibody-based detection as well as comparing arrays treated with wild-type OGT, 5N5A mutant OGT, or controls not treated with enzyme. Note: all CTD-stained arrays or control array raw files are contained in GSE107911_RAW.tar
Project description:Purpose: This study uses a high-throughput glycan microarray to evaluate the immunological evolution of antibodies to the glyco-antigen GD2. The goal is to determine germline and affinity mature antibody specificity and affinities/ Results: Affinity mature anti-GD2 antibodies 3F8 and ch14.18 had high affinity and were highly specific for the target GD2. Germline antibodies were also hihgly specific and had surprisingly high affinity. Conclusion: Antibodies to GD2 evolved from highly specific germlines. Highly specific germlines may be critical in evading autoimmunity issues.
Project description:Purpose: This study uses a high-throughput glycan microarray to evaluate the immunological evolution of antibodies to the glyco-antigen GD2. The goal is to determine germline and affinity mature antibody specificity and affinities/ Results: Affinity mature anti-GD2 antibodies 3F8 and ch14.18 had high affinity and were highly specific for the target GD2. Germline antibodies were also hihgly specific and had surprisingly high affinity. Conclusion: Antibodies to GD2 evolved from highly specific germlines. Highly specific germlines may be critical in evading autoimmunity issues.