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Mark T Bedford - One of the best experts on this subject based on the ideXlab platform.

  • the role of the prmt5 snd1 axis in hepatocellular carcinoma
    Epigenomes, 2021
    Co-Authors: Tanner Wright, Yalong Wang, Mark T Bedford
    Abstract:

    Arginine methylation is an essential post-translational modification (PTM) deposited by protein arginine methyltransferases (PRMTs) and recognized by Tudor domain-containing proteins. Of the nine mammalian PRMTs, PRMT5 is the primary enzyme responsible for the deposition of symmetric arginine methylation marks in cells. The staphylococcal nuclease and Tudor domain-containing 1 (SND1) effector protein is a key reader of the marks deposited by PRMT5. Both PRMT5 and SND1 are broadly expressed and their deregulation is reported to be associated with a range of disease phenotypes, including cancer. Hepatocellular carcinoma (HCC) is an example of a cancer type that often displays elevated PRMT5 and SND1 levels, and there is evidence that hyperactivation of this axis is oncogenic. Importantly, this pathway can be tempered with small-molecule inhibitors that target PRMT5, offering a therapeutic node for cancer, such as HCC, that display high PRMT5–SND1 axis activity. Here we summarize the known activities of this writer–reader pair, with a focus on their biological roles in HCC. This will help establish a foundation for treating HCC with PRMT5 inhibitors and also identify potential biomarkers that could predict sensitivity to this type of therapy.

  • genetic evidence for partial redundancy between the arginine methyltransferases carm1 and PRMT6
    Journal of Biological Chemistry, 2020
    Co-Authors: Donghang Cheng, Guozhen Gao, Alessandra Di Lorenzo, Sandrine Jayne, Michael O Hottiger, Stephane Richard, Mark T Bedford
    Abstract:

    CARM1 is a protein arginine methyltransferase (PRMT) that acts as a coactivator in a number of transcriptional programs. CARM1 orchestrates this coactivator activity in part by depositing the H3R17me2a histone mark in the vicinity of gene promoters that it regulates. However, the gross levels of H3R17me2a in CARM1 KO mice did not significantly decrease, indicating that other PRMT(s) may compensate for this loss. We thus performed a screen of type I PRMTs, which revealed that PRMT6 can also deposit the H3R17me2a mark in vitro. CARM1 knockout mice are perinatally lethal and display a reduced fetal size, whereas PRMT6 null mice are viable, which permits the generation of double knockouts. Embryos that are null for both CARM1 and PRMT6 are noticeably smaller than CARM1 null embryos, providing in vivo evidence of redundancy. Mouse embryonic fibroblasts (MEFs) from the double knockout embryos display an absence of the H3R17me2a mark during mitosis and increased signs of DNA damage. Moreover, using the combination of CARM1 and PRMT6 inhibitors suppresses the cell proliferation of WT MEFs, suggesting a synergistic effect between CARM1 and PRMT6 inhibitions. These studies provide direct evidence that PRMT6 also deposits the H3R17me2a mark and acts redundantly with CARM1.

  • PRMT1 loss sensitizes cells to PRMT5 inhibition.
    Nucleic acids research, 2019
    Co-Authors: Guozhen Gao, Liang Zhang, Oscar D. Villarreal, Ella Bedford, Phoebe Moh, Jianjun Shen, Xiaobing Shi, Mark T Bedford
    Abstract:

    PRMT5 is an arginine methyltransferase that accounts for the vast majority of the symmetric methylation in cells. PRMT5 exerts its function when complexed with MEP50/WDR77. This activity is often elevated in cancer cells and correlates with poor prognosis, making PRMT5 a therapeutic target. To investigate the PRMT5 signaling pathway and to identify genes whose loss-of-function sensitizes cancer cells to PRMT5 inhibition, we performed a CRISPR/Cas9 genetic screen in the presence of a PRMT5 inhibitor. We identified known components of the PRMT5 writer/reader pathway including PRMT5 itself, MEP50/WDR77, PPP4C, SMNDC1 and SRSF3. Interestingly, loss of PRMT1, the major asymmetric arginine methyltransferase, also sensitizes cells to PRMT5 inhibition. We investigated the interplay between PRMT5 and PRMT1, and found that combinatorial inhibitor treatment of small cell lung cancer and pancreatic cancer cell models have a synergistic effect. Furthermore, MTAP-deleted cells, which harbor an attenuated PRMT5-MEP50 signaling pathway, are generally more sensitive to PRMT1 inhibition. Together, these findings demonstrate that there is a degree of redundancy between the PRMT5 and PRMT1 pathways, even though these two enzymes deposit different types of arginine methylation marks. Targeting this redundancy provides a vulnerability for tumors carrying a co-deletion of MTAP and the adjacent CDKN2A tumor suppressor gene.

  • using oriented peptide array libraries to evaluate methylarginine specific antibodies and arginine methyltransferase substrate motifs
    Scientific Reports, 2016
    Co-Authors: Sitaram Gayatri, Martis W Cowles, Vidyasiri Vemulapalli, Donghang Cheng, Mark T Bedford
    Abstract:

    Signal transduction in response to stimuli relies on the generation of cascades of posttranslational modifications that promote protein-protein interactions and facilitate the assembly of distinct signaling complexes. Arginine methylation is one such modification, which is catalyzed by a family of nine protein arginine methyltransferases, or PRMTs. Elucidating the substrate specificity of each PRMT will promote a better understanding of which signaling networks these enzymes contribute to. Although many PRMT substrates have been identified, and their methylation sites mapped, the optimal target motif for each of the nine PRMTs has not been systematically addressed. Here we describe the use of Oriented Peptide Array Libraries (OPALs) to methodically dissect the preferred methylation motifs for three of these enzymes – PRMT1, CARM1 and PRMT9. In parallel, we show that an OPAL platform with a fixed methylarginine residue can be used to validate the methyl-specific and sequence-specific properties of antibodies that have been generated against different PRMT substrates, and can also be used to confirm the pan nature of some methylarginine-specific antibodies.

  • unique features of human protein arginine methyltransferase 9 prmt9 and its substrate rna splicing factor sf3b2
    Journal of Biological Chemistry, 2015
    Co-Authors: Andrea Hadjikyriacou, Yanzhong Yang, Alexsandra Espejo, Mark T Bedford
    Abstract:

    Abstract Human protein arginine methyltransferase 9 (PRMT9) symmetrically dimethylates arginine residues on splicing factor SF3B2 (SAP145) and has been functionally linked to the regulation of alternative splicing of pre-mRNA. Site-directed mutagenesis studies on this enzyme and its substrate had revealed essential unique residues in the double E loop and the importance of the C-terminal duplicated methyltransferase domain. In contrast to what had been observed with other PRMTs and their physiological substrates, a peptide containing the methylatable Arg-508 of SF3B2 was not recognized by PRMT9 in vitro. While amino acid substitutions of residues surrounding Arg-508 had no great effect on PRMT9 recognition of SF3B2, moving the arginine residue within this sequence abolished methylation. PRMT9 and PRMT5 are the only known mammalian enzymes capable of forming symmetric dimethylarginine (SDMA) residues as type II PRMTs. We demonstrate here that the specificity of these enzymes for their substrates is distinct and not redundant. The loss of PRMT5 activity in mouse embryo fibroblasts results in almost complete loss of SDMA, suggesting that PRMT5 is the primary SDMA-forming enzyme in these cells. PRMT9, with its duplicated methyltransferase domain and conserved sequence in the double E loop, appears to have a unique structure and specificity among PRMTs for methylating SF3B2 and potentially other polypeptides.

Adam Frankel - One of the best experts on this subject based on the ideXlab platform.

  • inconvenient truths for PRMT6 kinetic studies
    Journal of Biological Chemistry, 2012
    Co-Authors: Adam Frankel
    Abstract:

    Obianyo and Thompson assigned a rapid equilibrium random mechanism to PRMT6 in their recent article (1). We disagree with their conclusions and assessment of our work (2). PRMT crystal structures solved in complex with substrates and/or substrate analogs contradict their kinetic mechanism and support our sequential ordered mechanism in which S-adenosyl-l-methionine (AdoMet) binds first and S-adenosyl-l-homocysteine (AdoHcy) dissociates last from the enzyme because AdoMet/AdoHcy-binding pockets become buried underneath two α-helical segments when occupied (3–5). Obianyo and Thompson did not reconcile their kinetic mechanism with any structural or biophysical studies of PRMTs. In our previous work, we used a MS-based assay to measure AdoHcy or methylated peptides where appropriate to directly quantify these products (2). Our product inhibition studies for the monomethylated substrate provided solid evidence to support a sequential ordered mechanism. In contrast to our method, Obianyo and Thompson employed a gel-based assay to indirectly measure radioactivity associated with peptide methylation, where phosphorimages or raw densitometry data are not available for scrutiny. Their double-reciprocal plots consistently show line patterns indicative of the type of product inhibition claimed that do not fit with most of the data points displayed. The unfortunate consequence of their interpretation is a proposed kinetic mechanism for PRMT6 unsupported by their own experimental results and what has been reported in the literature (2–5).

  • a protein arginine n methyltransferase 1 prmt1 and 2 heteromeric interaction increases prmt1 enzymatic activity
    Biochemistry, 2011
    Co-Authors: Magnolia L Pak, Ted M Lakowski, Dylan Thomas, Mynol I Vhuiyan, Kristina Husecken, Adam Frankel
    Abstract:

    Protein arginine N-methyltransferases (PRMTs) act in signaling pathways and gene expression by methylating arginine residues within target proteins. PRMT1 is responsible for most cellular arginine methylation activity and can work independently or in collaboration with other PRMTs. In this study, we demonstrate a direct interaction between PRMT1 and PRMT2 using co-immunoprecipitation, bimolecular fluorescence complementation, and enzymatic assays. As a result of this interaction, PRMT2 stimulated PRMT1 activity, affecting its apparent Vmax and KM values in vitro and increasing the production of methylarginines in cells. Active site mutations and regional deletions from PRMT1 and -2 were also investigated, which demonstrated that complex formation required full-length, active PRMT1. Although the inhibition of methylation by adenosine dialdehyde prevented the interaction between PRMT1 and -2, it did not prevent the interaction between PRMT1 and a truncation mutant of PRMT2 lacking its Src homology 3 (SH3) d...

  • kinetic analysis of human protein arginine n methyltransferase 2 formation of monomethyl and asymmetric dimethyl arginine residues on histone h4
    Biochemical Journal, 2009
    Co-Authors: Ted M Lakowski, Adam Frankel
    Abstract:

    Protein arginine N-methyltransferases (PRMTs) methylate arginine residues within proteins using S -adenosyl-L-methionine (AdoMet) to form S -adenosyl-L-homocysteine and methylarginine residues. All PRMTs produce ω- N G -monomethylarginine (MMA) residues and either asymmetric ω- N G , N G -dimethylarginine (aDMA) or symmetric ω- N G , N ′ G -dimethylarginine (sDMA) residues, referred to as Type I or Type II activity respectively. Here we report methylation activity from PRMT2 and compare it with PRMT1 activity using UPLC-MS/MS (ultra-performance liquid chromatography–tandem MS), gel electrophoresis, and thin-layer chromatography. We show that PRMT2 is a Type I enzyme and that the ratio of aDMA to MMA produced by PRMTs 1 and 2 is dependent on the substrate, regardless of rate or K m , suggesting that the reactions for both enzymes are distributive rather than processive. Using UPLC-MS/MS we find that, for PRMT2, the dissociation constant ( K A s ) and K m of AdoMet and the K m of histone H4 are similar to values for PRMT1, whereas the PRMT2 k cat is 800-fold less than the PRMT1 k cat . Although PRMT2 activity is substantially lower than PRMT1 in vitro , the fact that both enzymes selectively methylate histone H4 suggest that PRMT2, like PRMT1, may act as a transcription co-activator through this modification.

  • prmt7 is a member of the protein arginine methyltransferase family with a distinct substrate specificity
    Journal of Biological Chemistry, 2004
    Co-Authors: Tina B Miranda, Mark Miranda, Adam Frankel
    Abstract:

    We have identified a mammalian arginine N-methyltransferase, PRMT7, that can catalyze the formation of ω-N^G-monomethylarginine in peptides. This protein is encoded by a gene on human chromosome 16q22.1 (human locus AK001502). We expressed a full-length human cDNA construct in Escherichia coli as a glutathione S-transferase (GST) fusion protein. We found that GST-tagged PRMT7 catalyzes the S-adenosyl-[methyl-^3H]-L-methionine-dependent methylation of the synthetic peptide GGPGGRGGPGG-NH_2 (R1). The radiolabeled peptide was purified by high-pressure liquid chromatography and acid hydrolyzed to free amino acids. When the hydrolyzed products were separated by high-resolution cation-exchange chromatography, we were able to detect one tritiated species which co-migrated with an ω-N^G-monomethylarginine standard. Surprisingly, GST-PRMT7 was not able to catalyze the in vitro methylation of a GST-fibrillarin (amino acids 1–148) fusion protein (GST-GAR), a methyl-accepting substrate for the previously characterized PRMT1, PRMT3, PRMT4, PRMT5, and PRMT6 enzymes. Nor was it able to methylate myelin basic protein or histone H2A, in vitro substrates of PRMT5. This specificity distinguishes PRMT7 from all of the other known arginine methyltransferases. An additional unique feature of PRMT7 is that it seems to have arisen from a gene duplication event and contains two putative AdoMet-binding motifs. To see if both motifs were necessary for activity, each putative domain was expressed as a GST-fusion and tested for activity with peptides R1 and R2 (acetyl-GGRGG-NH_2). These truncated proteins were enzymatically inactive, suggesting that both domains are required for functionality.

  • the novel human protein arginine n methyltransferase PRMT6 is a nuclear enzyme displaying unique substrate specificity
    Journal of Biological Chemistry, 2002
    Co-Authors: Adam Frankel, Neelu Yadav, Jaeho Lee, Tina L Branscombe, Mark T Bedford
    Abstract:

    Protein arginine methylation is a prevalent posttranslational modification in eukaryotic cells that has been implicated in signal transduction, the metabolism of nascent pre-RNA, and the transcriptional activation processes. In searching the human genome for protein arginine N-methyltransferase (PRMT) family members, a novel gene has been found on chromosome 1 that encodes for an apparent methyltransferase, PRMT6. The polypeptide chain of PRMT6 is 41.9 kDa consisting of a catalytic core sequence common to other PRMT enzymes. Expressed as a glutathione S-transferase fusion protein, PRMT6 demonstrates type I PRMT activity, capable of forming both omega-N(G)-monomethylarginine and asymmetric omega-N(G),N(G)-dimethylarginine derivatives on the recombinant glycine- and arginine-rich substrate in a processive manner with a specific activity of 144 pmol methyl groups transferred min(-1) mg(-1) enzyme. A comparison of substrate specificity reveals that PRMT6 is functionally distinct from two previously characterized type I enzymes, PRMT1 and PRMT4. In addition, PRMT6 displays automethylation activity; it is the first PRMT to do so. This novel human PRMT, which resides solely in the nucleus when fused to the green fluorescent protein, joins a family of enzymes with diverse functions within cells.

Andrea Hadjikyriacou - One of the best experts on this subject based on the ideXlab platform.

  • protein arginine methyltransferase product specificity is mediated by distinct active site architectures
    Journal of Biological Chemistry, 2016
    Co-Authors: Kanishk Jain, Andrea Hadjikyriacou, Erik W Debler, Rebeccah A Warmack, Peter Stavropoulos
    Abstract:

    In the family of protein arginine methyltransferases (PRMTs) that predominantly generate either asymmetric or symmetric dimethylarginine (SDMA), PRMT7 is unique in producing solely monomethylarginine (MMA) products. The type of methylation on histones and other proteins dictates changes in gene expression, and numerous studies have linked altered profiles of methyl marks with disease phenotypes. Given the importance of specific inhibitor development, it is crucial to understand the mechanisms by which PRMT product specificity is conferred. We have focused our attention on active-site residues of PRMT7 from the protozoan Trypanosoma brucei. We have designed 26 single and double mutations in the active site, including residues in the Glu-Xaa8-Glu (double E) loop and the Met-Gln-Trp sequence of the canonical Thr-His-Trp (THW) loop known to interact with the methyl-accepting substrate arginine. Analysis of the reaction products by high resolution cation exchange chromatography combined with the knowledge of PRMT crystal structures suggests a model where the size of two distinct subregions in the active site determines PRMT7 product specificity. A dual mutation of Glu-181 to Asp in the double E loop and Gln-329 to Ala in the canonical THW loop enables the enzyme to produce SDMA. Consistent with our model, the mutation of Cys-431 to His in the THW loop of human PRMT9 shifts its product specificity from SDMA toward MMA. Together with previous results, these findings provide a structural basis and a general model for product specificity in PRMTs, which will be useful for the rational design of specific PRMT inhibitors.

  • unique features of human protein arginine methyltransferase 9 prmt9 and its substrate rna splicing factor sf3b2
    Journal of Biological Chemistry, 2015
    Co-Authors: Andrea Hadjikyriacou, Yanzhong Yang, Alexsandra Espejo, Mark T Bedford
    Abstract:

    Abstract Human protein arginine methyltransferase 9 (PRMT9) symmetrically dimethylates arginine residues on splicing factor SF3B2 (SAP145) and has been functionally linked to the regulation of alternative splicing of pre-mRNA. Site-directed mutagenesis studies on this enzyme and its substrate had revealed essential unique residues in the double E loop and the importance of the C-terminal duplicated methyltransferase domain. In contrast to what had been observed with other PRMTs and their physiological substrates, a peptide containing the methylatable Arg-508 of SF3B2 was not recognized by PRMT9 in vitro. While amino acid substitutions of residues surrounding Arg-508 had no great effect on PRMT9 recognition of SF3B2, moving the arginine residue within this sequence abolished methylation. PRMT9 and PRMT5 are the only known mammalian enzymes capable of forming symmetric dimethylarginine (SDMA) residues as type II PRMTs. We demonstrate here that the specificity of these enzymes for their substrates is distinct and not redundant. The loss of PRMT5 activity in mouse embryo fibroblasts results in almost complete loss of SDMA, suggesting that PRMT5 is the primary SDMA-forming enzyme in these cells. PRMT9, with its duplicated methyltransferase domain and conserved sequence in the double E loop, appears to have a unique structure and specificity among PRMTs for methylating SF3B2 and potentially other polypeptides.

  • unique features of human protein arginine methyltransferase 9 prmt9 and its substrate rna splicing factor sf3b2
    Journal of Biological Chemistry, 2015
    Co-Authors: Andrea Hadjikyriacou, Yanzhong Yang, Alexsandra Espejo, Mark T Bedford
    Abstract:

    Human protein arginine methyltransferase (PRMT) 9 symmetrically dimethylates arginine residues on splicing factor SF3B2 (SAP145) and has been functionally linked to the regulation of alternative splicing of pre-mRNA. Site-directed mutagenesis studies on this enzyme and its substrate had revealed essential unique residues in the double E loop and the importance of the C-terminal duplicated methyltransferase domain. In contrast to what had been observed with other PRMTs and their physiological substrates, a peptide containing the methylatable Arg-508 of SF3B2 was not recognized by PRMT9 in vitro. Although amino acid substitutions of residues surrounding Arg-508 had no great effect on PRMT9 recognition of SF3B2, moving the arginine residue within this sequence abolished methylation. PRMT9 and PRMT5 are the only known mammalian enzymes capable of forming symmetric dimethylarginine (SDMA) residues as type II PRMTs. We demonstrate here that the specificity of these enzymes for their substrates is distinct and not redundant. The loss of PRMT5 activity in mouse embryo fibroblasts results in almost complete loss of SDMA, suggesting that PRMT5 is the primary SDMA-forming enzyme in these cells. PRMT9, with its duplicated methyltransferase domain and conserved sequence in the double E loop, appears to have a unique structure and specificity among PRMTs for methylating SF3B2 and potentially other polypeptides.

  • prmt9 is a type ii methyltransferase that methylates the splicing factor sap145
    Nature Communications, 2015
    Co-Authors: Sitaram Gayatri, Andrea Hadjikyriacou, Yanzhong Yang, Daehoon Kim, Cecilia Zuritalopez, Zheng Xia, Ryan L Kelly, Ailan Guo
    Abstract:

    The human genome encodes a family of nine protein arginine methyltransferases (PRMT1-9), whose members can catalyse three distinct types of methylation on arginine residues. Here we identify two spliceosome-associated proteins-SAP145 and SAP49-as PRMT9-binding partners, linking PRMT9 to U2 snRNP maturation. We show that SAP145 is methylated by PRMT9 at arginine 508, which takes the form of monomethylated arginine (MMA) and symmetrically dimethylated arginine (SDMA). PRMT9 thus joins PRMT5 as the only mammalian enzymes capable of depositing the SDMA mark. Methylation of SAP145 on Arg 508 generates a binding site for the Tudor domain of the Survival of Motor Neuron (SMN) protein, and RNA-seq analysis reveals gross splicing changes when PRMT9 levels are attenuated. These results identify PRMT9 as a nonhistone methyltransferase that primes the U2 snRNP for interaction with SMN.

Yanzhong Yang - One of the best experts on this subject based on the ideXlab platform.

  • unique features of human protein arginine methyltransferase 9 prmt9 and its substrate rna splicing factor sf3b2
    Journal of Biological Chemistry, 2015
    Co-Authors: Andrea Hadjikyriacou, Yanzhong Yang, Alexsandra Espejo, Mark T Bedford
    Abstract:

    Abstract Human protein arginine methyltransferase 9 (PRMT9) symmetrically dimethylates arginine residues on splicing factor SF3B2 (SAP145) and has been functionally linked to the regulation of alternative splicing of pre-mRNA. Site-directed mutagenesis studies on this enzyme and its substrate had revealed essential unique residues in the double E loop and the importance of the C-terminal duplicated methyltransferase domain. In contrast to what had been observed with other PRMTs and their physiological substrates, a peptide containing the methylatable Arg-508 of SF3B2 was not recognized by PRMT9 in vitro. While amino acid substitutions of residues surrounding Arg-508 had no great effect on PRMT9 recognition of SF3B2, moving the arginine residue within this sequence abolished methylation. PRMT9 and PRMT5 are the only known mammalian enzymes capable of forming symmetric dimethylarginine (SDMA) residues as type II PRMTs. We demonstrate here that the specificity of these enzymes for their substrates is distinct and not redundant. The loss of PRMT5 activity in mouse embryo fibroblasts results in almost complete loss of SDMA, suggesting that PRMT5 is the primary SDMA-forming enzyme in these cells. PRMT9, with its duplicated methyltransferase domain and conserved sequence in the double E loop, appears to have a unique structure and specificity among PRMTs for methylating SF3B2 and potentially other polypeptides.

  • unique features of human protein arginine methyltransferase 9 prmt9 and its substrate rna splicing factor sf3b2
    Journal of Biological Chemistry, 2015
    Co-Authors: Andrea Hadjikyriacou, Yanzhong Yang, Alexsandra Espejo, Mark T Bedford
    Abstract:

    Human protein arginine methyltransferase (PRMT) 9 symmetrically dimethylates arginine residues on splicing factor SF3B2 (SAP145) and has been functionally linked to the regulation of alternative splicing of pre-mRNA. Site-directed mutagenesis studies on this enzyme and its substrate had revealed essential unique residues in the double E loop and the importance of the C-terminal duplicated methyltransferase domain. In contrast to what had been observed with other PRMTs and their physiological substrates, a peptide containing the methylatable Arg-508 of SF3B2 was not recognized by PRMT9 in vitro. Although amino acid substitutions of residues surrounding Arg-508 had no great effect on PRMT9 recognition of SF3B2, moving the arginine residue within this sequence abolished methylation. PRMT9 and PRMT5 are the only known mammalian enzymes capable of forming symmetric dimethylarginine (SDMA) residues as type II PRMTs. We demonstrate here that the specificity of these enzymes for their substrates is distinct and not redundant. The loss of PRMT5 activity in mouse embryo fibroblasts results in almost complete loss of SDMA, suggesting that PRMT5 is the primary SDMA-forming enzyme in these cells. PRMT9, with its duplicated methyltransferase domain and conserved sequence in the double E loop, appears to have a unique structure and specificity among PRMTs for methylating SF3B2 and potentially other polypeptides.

  • prmt9 is a type ii methyltransferase that methylates the splicing factor sap145
    Nature Communications, 2015
    Co-Authors: Sitaram Gayatri, Andrea Hadjikyriacou, Yanzhong Yang, Daehoon Kim, Cecilia Zuritalopez, Zheng Xia, Ryan L Kelly, Ailan Guo
    Abstract:

    The human genome encodes a family of nine protein arginine methyltransferases (PRMT1-9), whose members can catalyse three distinct types of methylation on arginine residues. Here we identify two spliceosome-associated proteins-SAP145 and SAP49-as PRMT9-binding partners, linking PRMT9 to U2 snRNP maturation. We show that SAP145 is methylated by PRMT9 at arginine 508, which takes the form of monomethylated arginine (MMA) and symmetrically dimethylated arginine (SDMA). PRMT9 thus joins PRMT5 as the only mammalian enzymes capable of depositing the SDMA mark. Methylation of SAP145 on Arg 508 generates a binding site for the Tudor domain of the Survival of Motor Neuron (SMN) protein, and RNA-seq analysis reveals gross splicing changes when PRMT9 levels are attenuated. These results identify PRMT9 as a nonhistone methyltransferase that primes the U2 snRNP for interaction with SMN.

Xiangguo Liu - One of the best experts on this subject based on the ideXlab platform.

  • the arginine methyltransferase prmt5 and prmt1 distinctly regulate the degradation of anti apoptotic protein cflarl in human lung cancer cells
    Journal of Experimental & Clinical Cancer Research, 2019
    Co-Authors: Yidan Lin, Xiangguo Liu
    Abstract:

    CFLARL, also known as c-FLIPL, is a critical anti-apoptotic protein that inhibits activation of caspase 8 in mammalian cells. Previous studies have shown that arginine 122 of CFLARL can be mono-methylated. However, the precise role of arginine methyltransferase of CFLARL remains unknown. PRMT5 and PRMT1, which are important members of the PRMT family, catalyze the transfer of methyl groups to the arginine of substrate proteins. PRMT5 can monomethylate or symmetrically dimethylate arginine residues, while PRMT1 can monomethylate or asymmetrically dimethylate arginine residues. Lung cancer cells were cultured following the standard protocol and the cell lysates were prepared to detect the given proteins by Western Blot analysis, and the protein interaction was assayed by co-immunoprecipitation (Co-IP) or GST pull-down assay. CFLARL ubiquitination level was evaluated by proteasomal inhibitor treatment combined with HA-Ub transfection and WB assay. PRMT1 and PRMT5 genes were knocked down by siRNA technique. We show that PRMT5 up-regulated the protein levels of CFLARL by decreasing the ubiquitination and increasing its protein level. Additionally, PRMT1 down-regulated the protein level of CFLARL by increasing the ubiquitination and degradation. The overexpression of PRMT5 can inhibit the interaction between CFLARL and ITCH, which has been identified as an E3 ubiquitin ligase of CFLARL, while overexpressed PRMT1 enhances the interaction between CFLARL and ITCH. Furthermore, we verified that dead mutations of PRMT5 or PRMT1 have the same effects on CFLARL as the wild-type ones have, suggesting it is the physical interaction between CFLAR and PRMT1/5 that regulates CFLARL degradation other than its enzymatic activity. Finally, we showed that PRMT5 and PRMT1 could suppress or facilitate apoptosis induced by doxorubicin or pemetrexed by affecting CFLARL in NSCLC cells. PRMT5 and PRMT1 mediate the distinct effects on CFLARL degradation by regulating the binding of E3 ligase ITCH in NSCLC cells. This study identifies a cell death mechanism that is fine-tuned by PRMT1/5 that modulate CFLARL degradation in human NSCLC cells.

  • The arginine methyltransferase PRMT5 and PRMT1 distinctly regulate the degradation of anti-apoptotic protein CFLARL in human lung cancer cells
    BMC, 2019
    Co-Authors: Yidan Lin, Xiangguo Liu
    Abstract:

    Abstract Background CFLARL, also known as c-FLIPL, is a critical anti-apoptotic protein that inhibits activation of caspase 8 in mammalian cells. Previous studies have shown that arginine 122 of CFLARL can be mono-methylated. However, the precise role of arginine methyltransferase of CFLARL remains unknown. PRMT5 and PRMT1, which are important members of the PRMT family, catalyze the transfer of methyl groups to the arginine of substrate proteins. PRMT5 can monomethylate or symmetrically dimethylate arginine residues, while PRMT1 can monomethylate or asymmetrically dimethylate arginine residues. Methods Lung cancer cells were cultured following the standard protocol and the cell lysates were prepared to detect the given proteins by Western Blot analysis, and the protein interaction was assayed by co-immunoprecipitation (Co-IP) or GST pull-down assay. CFLARL ubiquitination level was evaluated by proteasomal inhibitor treatment combined with HA-Ub transfection and WB assay. PRMT1 and PRMT5 genes were knocked down by siRNA technique. Results We show that PRMT5 up-regulated the protein levels of CFLARL by decreasing the ubiquitination and increasing its protein level. Additionally, PRMT1 down-regulated the protein level of CFLARL by increasing the ubiquitination and degradation. The overexpression of PRMT5 can inhibit the interaction between CFLARL and ITCH, which has been identified as an E3 ubiquitin ligase of CFLARL, while overexpressed PRMT1 enhances the interaction between CFLARL and ITCH. Furthermore, we verified that dead mutations of PRMT5 or PRMT1 have the same effects on CFLARL as the wild-type ones have, suggesting it is the physical interaction between CFLAR and PRMT1/5 that regulates CFLARL degradation other than its enzymatic activity. Finally, we showed that PRMT5 and PRMT1 could suppress or facilitate apoptosis induced by doxorubicin or pemetrexed by affecting CFLARL in NSCLC cells. Conclusions PRMT5 and PRMT1 mediate the distinct effects on CFLARL degradation by regulating the binding of E3 ligase ITCH in NSCLC cells. This study identifies a cell death mechanism that is fine-tuned by PRMT1/5 that modulate CFLARL degradation in human NSCLC cells

  • Additional file 1: of The arginine methyltransferase PRMT5 and PRMT1 distinctly regulate the degradation of anti-apoptotic protein CFLARL in human lung cancer cells
    2019
    Co-Authors: Yidan Lin, Xiangguo Liu
    Abstract:

    Figure S1. Interaction domains between CFLARL and PRMT5 and PRMT1. A HEK293FT cells were transfected with the pcDNA3.1-FLAG-CFLARL plasmids and co-transfected with all sections of PRMT5 and the control plasmid. Then, the cells were harvested and prepared for the IP assay after 16 h. The cells were treated with 20 μmol/L MG132 for 4 h. The precipitated proteins were analyzed by western blotting. B HEK293FT cells were transfected with the pcDNA3.1-FLAG-CFLARL plasmids and co-transfected with the section of PRMT1 and the control plasmid. Then, the cells were harvested and prepared for the IP assay after 16 h. The cells were treated with 20 μmol/L MG132 for 4 h. The precipitated proteins were analyzed by western blotting. C HEK293FT cells were transfected with the pcDNA3.1-MYC-PRMT5 plasmids and co-transfected with all sections of CFLARL and the control plasmid. The cells were the harvested and prepared for the IP assay after 20 h, and the precipitated proteins were analyzed by western blotting. D HEK293FT cells were transfected with the pcDNA3.1-MYC-PRMT1 plasmids and co-transfected with all sections of CFLARL and the control plasmid. The cells were harvested, prepared for the IP assay after 16 h, and treated with 20 μmol/L MG132 for 4 h. The expression of the corresponding protein was calculated as described in (C). Figure S2. PRMT5 and PRMT1 modulated apoptosis in NSCLC cells. A and B H460 cells were seeded in 6-well plates. PcDNA3.1-PRMT5 were transfected for 24 h. Cells were treated with pemetrexed [5.0 μM] for 48 h. Cells were collected for Flow Cytometry analysis. C and D H460 cells were seeded in 6-well plates. PRMT5 siRNA were transfected for 48 h. Cells were treated with pemetrexed [5.0 μM] for 48 h. Cells were collected for Flow Cytometry analysis. E and F A549 cells were seeded in 6-well plates. PRMT1 siRNA were transfected for 48 h. Cells were treated with pemetrexed [5.0 μM] for 48 h. Cells were collected for Flow Cytometry analysis. (DOCX 14 kb