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Tao, W. A.

Publications and source records attributed to Tao, W. A..

6 recordsLinked to original sources

Chemical Proteomic Profiling of the Histaminylation Proteome in Cancer Cells Unveils Uncharted Epigenetic Marks on Core Histones

Histamine is a key signaling molecule in pathophysiology that can exhibit significant regulatory roles in diverse health and disease status. Besides the well-studied noncovalent interactions between histamine and its receptors, protein histaminylation is a recently discovered mechanism of action, through which histamine regulates cellular signaling pathways in a covalent modification manner. Histaminylation is an emerging protein post-translational modification, where an isopeptide bond is formed between the histamine primary amine and {gamma}-carboxyl group of glutamine through a transamidation reaction catalyzed by transglutaminase 2 (TGM2). However, due to the lack of efficient pan-specific antibodies targeting histaminylated glutamine, the histaminylation proteome in cells remains poorly explored. Here, we report the design and development of a novel N{tau}-propargylated histamine (N{tau}-PH) probe as well as its successful application in chemical proteomic profiling of the histaminylation proteome in cancer cells. Notably, new TGM2-catalyzed epigenetic marks on core histones, e.g., H2AX-Q84 and Q104 histaminylation, have been identified from cancer cells and verified. Lastly, the crosstalk between H2AX histaminylation and {gamma}H2AX formation was discovered in this study, suggesting that TGM2-mediated histaminylation plays a critical role in DNA damage responses.

biochemistry↗

NRMLncR, a myocyte-enriched long non-coding RNA, enhances myogenesis in mouse

Myogenesis is a stepwise process encompassing myogenic progenitor proliferation, lineage commitment, differentiation, myocyte fusion, and myotube maturation, and it is orchestrated by myogenic regulatory factors (MRFs) together with signaling pathways that coordinate these transitions. Long noncoding RNAs (lncRNAs) have emerged as important regulators of muscle development and regeneration, yet how lncRNAs integrate with canonical signaling networks to shape myogenic progression remains incompletely defined. Here, we identify a novel myocyte-enriched, Notch-repressed myogenic lncRNA (NRMLncR, known as A930003A15Rik), as a previously uncharacterized regulator of mouse myogenesis. The expression of NRMLncR is robustly induced during primary myoblast activation and differentiation. Loss-of-function analyses show that knockdown of NRMLncR impairs myogenic differentiation, accompanied by reduced expression of key myogenic genes. In contrast, adenovirus-mediated overexpression of NRMLncR enhances myogenic differentiation in vitro and is associated with increased muscle fiber size in vivo. Mechanistically, MyoD and MyoG occupy the NRMLncR promoter and promote its transcription during myogenic differentiation. NRMLncR knockdown alerts the transcription of nearby genes, suggesting its function through a cis-regulatory mechanism. RNA pull-down assays further identify an interaction between NRMLncR and the RNA-binding protein CELF1. Together, these findings establish NRMLncR as a novel Notch-associated lncRNA that promotes myogenic differentiation and provide insight into lncRNA-dependent regulation of the myogenic program.

genetics↗

PBRM1-Dependent PBAF Targeting is Required for EMT and Metastasis in Breast Cancer

SWI/SNF chromatin remodelers utilize ATP to mobilize nucleosomes on DNA and are represented by three biochemically distinct subcomplexes, the more abundant cBAF and the less abundant PBAF and GBAF subcomplexes. Patient mutations and genetic studies have identified important roles for PBAF subunits in development and disease; however, relating PBAF-mediated phenotypes to biochemical function in chromatin regulation and gene expression has been challenging. Further complicating matters, cell-based systems often do not reflect the phenotypes and genotypes observed with PBAF mutations in vivo. Here we show that the PBRM1 subunit of PBAF is critical for the completion of TGFB1-mediated epithelial-mesenchymal transition of mammary cells in vitro as well as the metastasis of murine breast cancers in vivo. Using epigenomics to profile different stages of EMT, we find that PBRM1 is necessary for targeting PBAF to inducible promoters marked by H3K14ac alone. We further find that PBRM1 facilitates DNA accessibility at sites bound by TGF{beta}1-inducible transcription factors, such as Atf3, for the induction of genes involved in migration, cell survival, and inflammation. Our model allows us to separate constitutive vs inducible gene expression to help explain some of the context-dependent phenotypes observed with PBRM1 deletion. In addition, we provide evidence that while PBRM1 deletions can promote the initiation of certain cancers in early stages, PBAF may be a vulnerability in late-stage metastatic cancers.

molecular biology↗

Multiplexed Data-Independent Acquisition (mDIA) to Profile Extracellular Vesicle Proteomes

Extracellular vesicles (EVs) have gained increasing attention with their intriguing biological functions and their molecular cargoes serving as potential biomarkers for various diseases, including cancers. A relatively lower abundance of EV proteins compared to cellular counterparts necessitates sensitive and accurate quantitative proteomic strategies. Multiplexed proteomics combined with data-independent acquisition (mDIA) has shown promise for improving sensitivity and quantification over traditional DDA and label-free methods. Despite this, mDIA pipelines that utilize various types of spectral libraries and search software suites have not been thoroughly evaluated with EV proteome samples. In this study, we aim to establish a robust mDIA pipeline based on dimethyl labeling for quantitative proteomics of EVs. EVs were isolated using the extracellular vesicle total recovery and purification (EVtrap) technique and processed directly through an on-bead one-pot sample preparation workflow to obtain digested peptides. We evaluated different mDIA pipelines, including library-free and library-based DIA on the timsTOF HT platform. Results showed that library-based DIA, with project-specific spectral libraries generated from StageTip-based fractionation, outperformed other pipelines in protein identification and quantification. We demonstrated for the first time EV proteome landscape changes caused by the IDH1 mutation and inhibitor treatment in intrahepatic cholangiocarcinoma, highlighting the utility of mDIA in EV-based biomarker discovery.

biochemistry↗

Discovery of Chirally-dependent Protein O-2-Hydroxyglutarylation by D2HG and L2HG

Mutations in isocitrate dehydrogenase 1 (IDH1) and IDH2 are common in multiple types of human cancer, leading to the accumulation of D-2-hydroxyglutarate (D2HG) and the promotion of tumorigenesis1. Here we discovered a novel O-2- hydroxyglutarylation by D2HG using chemical proteomics and further revealed distinct chiral preferences for D/L2HG modifications. Notably, we identified two kinases, MRCKA and SLK, modified by D2HG and L2HG respectively, and detected reduced phosphorylation of their substrates, suggesting an inhibitory effect of D/L 2HG modifications on the kinases activity.

biochemistry↗

FAM210A mediates an inter-organelle crosstalk essential for protein synthesis and muscle growth in mouse

Mitochondria are not only essential for energy production in eukaryocytes but also a key regulator of intracellular signaling. Here, we report an unappreciated role of mitochondria in regulating cytosolic protein translation in skeletal muscle cells (myofibers). We show that the expression of mitochondrial protein FAM210A (Family With Sequence Similarity 210 Member A) is positively associated with muscle mass in mice and humans. Muscle-specific Myl1Cre-driven Fam210a knockout (Fam210aMKO) in mice reduces mitochondrial density and function, leading to progressive muscle atrophy and premature death. Metabolomic and biochemical analyses reveal that Fam210aMKO reverses the oxidative TCA cycle towards the reductive direction, resulting in acetyl-CoA accumulation and hyperacetylation of cytosolic proteins. Specifically, hyperacetylation of several ribosomal proteins leads to disassembly of ribosomes and translational defects. Transplantation of Fam210aMKO mitochondria into wildtype myoblasts is sufficient to elevate protein acetylation in recipient cells. These findings reveal a novel crosstalk between the mitochondrion and ribosome mediated by FAM210A.

cell biology↗