Identification of WNK1 as a therapeutic target to suppress IgH/MYC expression in multiple myeloma.

Multiple myeloma (MM) remains an incurable hematological malignancy demanding innovative therapeutic strategies. Targeting MYC, the notorious yet traditionally undruggable oncogene, presents an appealing avenue. Here, using a genome-scale CRISPR-Cas9 screen, we identify the WNK lysine-deficient protein kinase 1 (WNK1) as a regulator of MYC expression in MM cells.

Prosurvival kinase PIM2 is a therapeutic target for eradication of chronic myeloid leukemia stem cells.

A major obstacle to curing chronic myeloid leukemia (CML) is the intrinsic resistance of CML stem cells (CMLSCs) to the drug imatinib mesylate (IM). Prosurvival genes that are preferentially expressed in CMLSCs compared with normal hematopoietic stem cells (HSCs) represent potential therapeutic targets for selectively eradicating CMLSCs. However, the discovery of such preferentially expressed genes has been hampered by the inability to completely separate CMLSCs from HSCs, which display a very similar set of surface markers.

PRMT2 interacts with splicing factors and regulates the alternative splicing of BCL-X.

Protein arginine N-methyltransferase 2 (PRMT2) functions in JAK-STAT and Wnt/β-catenin signalling pathways, serves as a nuclear receptor-dependent transcriptional co-activator, and represses NF-κB and E2F1 transcription factor activities to promote apoptosis. We have previously demonstrated that PRMT2 interacts with PRMT1 and increases its activity. Here, we reveal associations using proteomics between the PRMT2 SH3 domain and splicing factors including Src-associated in mitosis 68 kDa protein (SAM68), a PRMT1 substrate and trans-acting factor that mediates BCL-X alternative splicing.

Arginine methylation in yeast proteins during stationary-phase growth and heat shock.

Arginine methyltransferases (RMTs) catalyze the methylation of arginine residues on proteins. We examined the effects of log-phase growth, stationary-phase growth, and heat shock on the formation of methylarginines on yeast proteins to determine if the conditions favor a particular type of methylation. Utilizing linear ion trap mass spectrometry, we identify methylarginines in wild-type and RMT deletion yeast strains using secondary product ion scans (MS(3)), and quantify the methylarginines using multiple reaction monitoring (MRM).

The CREB Coactivator CRTC2 Is a Lymphoma Tumor Suppressor that Preserves Genome Integrity through Transcription of DNA Mismatch Repair Genes.

The CREB-regulated transcription coactivator CRTC2 stimulates CREB target gene expression and has a well-established role in modulating glucose and lipid metabolism. Here, we find, unexpectedly, that loss of CRTC2, as well as CREB1 and its coactivator CREB-binding protein (CBP), results in a deficiency in DNA mismatch repair (MMR) and a resultant increased mutation frequency. We show that CRTC2, CREB1, and CBP are transcriptional activators of well-established MMR genes, including EXO1, MSH6, PMS1, and POLD2.

A large-scale RNAi-based mouse tumorigenesis screen identifies new lung cancer tumor suppressors that repress FGFR signaling.

Unlabelled: To discover new tumor-suppressor genes (TSG), we developed a functional genomics approach in which immortalized but nontumorigenic cells were stably transduced with large-scale shRNA pools and tested for tumor formation in mice. Identification of shRNAs in resulting tumors revealed candidate TSGs, which were validated experimentally and by analyzing expression in human tumor samples. Using this approach, we identified 24 TSGs that were significantly downregulated in human lung squamous cell carcinomas (hLSCC).

MS³ fragmentation patterns of monomethylarginine species and the quantification of all methylarginine species in yeast using MRM³.

Protein arginine methylation is one of the epigenetic modifications to proteins that is studied in yeast and is known to be involved in a number of human diseases. All eukaryotes produce Nη-monomethylarginine (ηMMA), asymmetric Nη1, Nη1-dimethylarginine (aDMA), and most produce symmetric Nη1, Nη2-dimethylarginine (sDMA) on proteins, but only yeast produce Nδ-monomethylarginine (δMMA). It has proven difficult to differentiate among all of these methylarginines using mass spectrometry.

A protein arginine N-methyltransferase 1 (PRMT1) and 2 heteromeric interaction increases PRMT1 enzymatic activity.

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.

Förster resonance energy transfer measurements of cofactor-dependent effects on protein arginine N-methyltransferase homodimerization.

Protein arginine N-methyltransferase (PRMT) dimerization is required for methyl group transfer from the cofactor S-adenosyl-L-methionine (AdoMet) to arginine residues in protein substrates, forming S-adenosyl-L-homocysteine (AdoHcy) and methylarginine residues. In this study, we use Förster resonance energy transfer (FRET) to determine dissociation constant (K(D)) values for dimerization of PRMT1 and PRMT6. By attaching monomeric Cerulean and Citrine fluorescent proteins to their N-termini, fluorescent PRMTs are formed that exhibit similar enzyme kinetics to unconjugated PRMTs.