A group 3 medulloblastoma stem cell program is maintained by OTX2-mediated alternative splicing.

OTX2 is a transcription factor and known driver in medulloblastoma (MB), where it is amplified in a subset of tumours and overexpressed in most cases of group 3 and group 4 MB. Here we demonstrate a noncanonical role for OTX2 in group 3 MB alternative splicing. OTX2 associates with the large assembly of splicing regulators complex through protein-protein interactions and regulates a stem cell splicing program.

Impaired OTUD7A-dependent Ankyrin regulation mediates neuronal dysfunction in mouse and human models of the 15q13.3 microdeletion syndrome.

Copy number variations (CNVs) are associated with psychiatric and neurodevelopmental disorders (NDDs), and most, including the recurrent 15q13.3 microdeletion disorder, have unknown disease mechanisms. We used a heterozygous 15q13.

BMI1 is a therapeutic target in recurrent medulloblastoma.

Medulloblastoma (MB) is the most frequent malignant pediatric brain tumor, representing 20% of newly diagnosed childhood central nervous system malignancies. Although advances in multimodal therapy yielded a 5-year survivorship of 80%, MB still accounts for the leading cause of childhood cancer mortality. In this work, we describe the epigenetic regulator BMI1 as a novel therapeutic target for the treatment of recurrent human Group 3 MB, a childhood brain tumor for which there is virtually no treatment option beyond palliation.

OTUD7A Regulates Neurodevelopmental Phenotypes in the 15q13.3 Microdeletion Syndrome.

Copy-number variations (CNVs) are strong risk factors for neurodevelopmental and psychiatric disorders. The 15q13.3 microdeletion syndrome region contains up to ten genes and is associated with numerous conditions, including autism spectrum disorder (ASD), epilepsy, schizophrenia, and intellectual disability; however, the mechanisms underlying the pathogenesis of 15q13.

IL-17 receptor signaling inhibits C/EBPbeta by sequential phosphorylation of the regulatory 2 domain.

Interleukin-17 (IL-17), the hallmark cytokine of T helper 17 (T(H)17) cells, signals through a distinct receptor subclass, yet little is known about the mechanisms involved. IL-17 activates the expression of target genes through the actions of the transcription factors nuclear factor kappaB (NF-kappaB), CAAT enhancer binding protein delta (C/EBPdelta), and C/EBPbeta. The adaptor proteins tumor necrosis factor receptor-associated factor 6 (TRAF6) and Act1 are upstream of NF-kappaB and C/EBPdelta, but the regulation of C/EBPbeta remains undefined.

Prevention of amino acid conversion in SILAC experiments with embryonic stem cells.

Recent studies using stable isotope labeling with amino acids in culture (SILAC) in quantitative proteomics have made mention of the problematic conversion of isotope-coded arginine to proline in cells. The resulting converted proline peptide divides the heavy peptide ion signal causing inaccuracy when compared with the light peptide ion signal. This is of particular concern as it can effect up to half of all peptides in a proteomic experiment.

Initiation of Wnt signaling: control of Wnt coreceptor Lrp6 phosphorylation/activation via frizzled, dishevelled and axin functions.

Canonical Wnt/beta-catenin signaling has central roles in development and diseases, and is initiated by the action of the frizzled (Fz) receptor, its coreceptor LDL receptor-related protein 6 (Lrp6), and the cytoplasmic dishevelled (Dvl) protein. The functional relationships among Fz, Lrp6 and Dvl have long been enigmatic. We demonstrated previously that Wnt-induced Lrp6 phosphorylation via glycogen synthase kinase 3 (Gsk3) initiates Wnt/beta-catenin signaling.

R-spondin1 is a high affinity ligand for LRP6 and induces LRP6 phosphorylation and beta-catenin signaling.

R-spondin proteins are newly identified secreted molecules that activate beta-catenin signaling. However, the mechanism of R-spondin action and its relationship with Wnt signaling remain unclear. Here we show that human R-spondin1 (hRspo1) is a high affinity ligand for the Wnt co-receptor LRP6 (K(d) = 1.

Glycogen synthase kinase 3, circadian rhythms, and bipolar disorder: a molecular link in the therapeutic action of lithium.

Background: Bipolar disorder (BPD) is a widespread condition characterized by recurring states of mania and depression. Lithium, a direct inhibitor of glycogen synthase kinase 3 (GSK3) activity, and a mainstay in BPD therapeutics, has been proposed to target GSK3 as a mechanism of mood stabilization. In addition to mood imbalances, patients with BPD often suffer from circadian disturbances.

A dual-kinase mechanism for Wnt co-receptor phosphorylation and activation.

Signalling by the Wnt family of secreted lipoproteins has essential functions in development and disease. The canonical Wnt/beta-catenin pathway requires a single-span transmembrane receptor, low-density lipoprotein (LDL)-receptor-related protein 6 (LRP6), whose phosphorylation at multiple PPPSP motifs is induced upon stimulation by Wnt and is critical for signal transduction. The kinase responsible for LRP6 phosphorylation has not been identified.

Inhibition of TGFbeta signaling potentiates the FGF-2-induced stimulation of cardiomyocyte DNA synthesis.

Objective: Added transforming growth factor beta (TGFbeta) inhibits the proliferation of immature cardiomyocytes. We have now examined the hypothesis that suppression of endogenous TGFbeta signaling will boost the proliferative response (DNA synthesis) of cardiac myocytes to serum and/or to the mitogenic factor fibroblast growth factor-2 (FGF-2).

Methods And Results: Overexpression of a kinase-deficient TGFbeta type II receptor (TGFbetaRIIDeltaKD) resulted in a 2.