Attenuation of PKC{delta} enhances metabolic activity and promotes expansion of blood progenitors
A finely tuned balance of self-renewal, differentiation, proliferation, and survival governs the pool size and regenerative capacity of blood-forming hematopoietic stem and progenitor cells (HSPCs). Here, we report that protein kinase C delta (PKC) is a critical regulator of adult HSPC number and function that couples the proliferative and metabolic activities of HSPCs. PKC-deficient mice showed a pronounced increase in HSPC numbers, increased competence in reconstituting lethally irradiated recipients, enhanced long-term competitive advantage in serial transplantation studies, and an augmented HSPC recovery during stress....
Source: EMBO Journal - December 14, 2018 Category: Molecular Biology Authors: Rao, T. N., Gupta, M. K., Softic, S., Wang, L. D., Jang, Y. C., Thomou, T., Bezy, O., Kulkarni, R. N., Kahn, C. R., Wagers, A. J. Tags: Immunology, Metabolism, Stem Cells Articles Source Type: research
Chemical genetic identification of CDKL5 substrates reveals its role in neuronal microtubule dynamics
Loss-of-function mutations in CDKL5 kinase cause severe neurodevelopmental delay and early-onset seizures. Identification of CDKL5 substrates is key to understanding its function. Using chemical genetics, we found that CDKL5 phosphorylates three microtubule-associated proteins: MAP1S, EB2 and ARHGEF2, and determined the phosphorylation sites. Substrate phosphorylations are greatly reduced in CDKL5 knockout mice, verifying these as physiological substrates. In CDKL5 knockout mouse neurons, dendritic microtubules have longer EB3-labelled plus-end growth duration and these altered dynamics are rescued by reduction of MAP1S le...
Source: EMBO Journal - December 14, 2018 Category: Molecular Biology Authors: Baltussen, L. L., Negraes, P. D., Silvestre, M., Claxton, S., Moeskops, M., Christodoulou, E., Flynn, H. R., Snijders, A. P., Muotri, A. R., Ultanir, S. K. Tags: Cell Adhesion, Polarity & Cytoskeleton, Genetics, Gene Therapy & Genetic Disease, Post-translational Modifications, Proteolysis & Proteomics Articles Source Type: research
Ultrafast optogenetic stimulation of the auditory pathway by targeting-optimized Chronos
In conclusion, efficient virus-mediated expression of targeting-optimized Chronos-ES/TS achieves ultrafast optogenetic control of neurons. (Source: EMBO Journal)
Source: EMBO Journal - December 14, 2018 Category: Molecular Biology Authors: Keppeler, D., Merino, R. M., Lopez de la Morena, D., Bali, B., Huet, A. T., Gehrt, A., Wrobel, C., Subramanian, S., Dombrowski, T., Wolf, F., Rankovic, V., Neef, A., Moser, T. Tags: Methods & Resources, Neuroscience Source Type: research
Phosphoproteomic screening identifies physiological substrates of the CDKL5 kinase
Mutations in the gene encoding the protein kinase CDKL5 cause a debilitating neurodevelopmental disease termed CDKL5 disorder. The impact of these mutations on CDKL5 function is poorly understood because the substrates and cellular processes controlled by CDKL5 are unclear. Here, we describe a quantitative phosphoproteomic screening which identified MAP1S, CEP131 and DLG5—regulators of microtubule and centrosome function—as cellular substrates of CDKL5. Antibodies against MAP1S phospho-Ser900 and CEP131 phospho-Ser35 confirmed CDKL5-dependent phosphorylation of these targets in human cells. The phospho-acceptor...
Source: EMBO Journal - December 14, 2018 Category: Molecular Biology Authors: Munoz, I. M., Morgan, M. E., Peltier, J., Weiland, F., Gregorczyk, M., Brown, F. C., Macartney, T., Toth, R., Trost, M., Rouse, J. Tags: Cell Adhesion, Polarity & Cytoskeleton, Genetics, Gene Therapy & Genetic Disease, Post-translational Modifications, Proteolysis & Proteomics Resource Source Type: research
CNOT6L couples the selective degradation of maternal transcripts to meiotic cell cycle progression in mouse oocyte
This study provides the first direct genetic evidence that CCR4–NOT-dependent and particularly CNOT6L-dependent decay of selective maternal mRNAs is a prerequisite for meiotic maturation of oocytes. (Source: EMBO Journal)
Source: EMBO Journal - December 14, 2018 Category: Molecular Biology Authors: Sha, Q.-Q., Yu, J.-L., Guo, J.-X., Dai, X.-X., Jiang, J.-C., Zhang, Y.-L., Yu, C., Ji, S.-Y., Jiang, Y., Zhang, S.-Y., Shen, L., Ou, X.-H., Fan, H.-Y. Tags: Cell Cycle, Development & Differentiation, RNA Biology Articles Source Type: research
The I{kappa}B kinase complex is a regulator of mRNA stability
The IB kinase (IKK) is considered to control gene expression primarily through activation of the transcription factor NF-B. However, we show here that IKK additionally regulates gene expression on post-transcriptional level. IKK interacted with several mRNA-binding proteins, including a Processing (P) body scaffold protein, termed enhancer of decapping 4 (EDC4). IKK bound to and phosphorylated EDC4 in a stimulus-sensitive manner, leading to co-recruitment of P body components, mRNA decapping proteins 1a and 2 (DCP1a and DCP2) and to an increase in P body numbers. Using RNA sequencing, we identified scores of transcripts wh...
Source: EMBO Journal - December 14, 2018 Category: Molecular Biology Authors: Mikuda, N., Kolesnichenko, M., Beaudette, P., Popp, O., Uyar, B., Sun, W., Tufan, A. B., Perder, B., Akalin, A., Chen, W., Mertins, P., Dittmar, G., Hinz, M., Scheidereit, C. Tags: Immunology, RNA Biology, Signal Transduction Articles Source Type: research
More is not always better: hyperglutamylation leads to neurodegeneration
Post-translational modifications of tubulin can regulate the dynamics and mechanical properties of microtubules and their interactions with different proteins, such as molecular motors. Two studies now demonstrate that excessive accumulation of a specific modification, polyglutamylation, leads to neurodegeneration in mice and humans, likely due to defects in axonal microtubule-based transport. (Source: EMBO Journal)
Source: EMBO Journal - December 3, 2018 Category: Molecular Biology Authors: Akhmanova, A., Hoogenraad, C. C. Tags: Neuroscience, Post-translational Modifications, Proteolysis & Proteomics News [amp ] Views Source Type: research
Optogenetic control of morphogenesis goes 3D
The generation of form in living embryos, a process termed "morphogenesis" from the Greek word μooacute;, is one of the most fascinating unsolved problems in biology. In embryonic epithelia, most attention has been paid to events occurring at the apical surface of epithelia, particularly the regulation of actomyosin contractility during morphogenetic change. In a new report, De Renzis and colleagues demonstrate a key role for regulated actomyosin contractility at the basal surface of the epithelium during formation of the first epithelial fold in Drosophila (the "ventral furrow") (Krueger et al, 2018). (Source: EMBO Journal)
Source: EMBO Journal - December 3, 2018 Category: Molecular Biology Authors: Thompson, B. J. Tags: Cell Adhesion, Polarity & Cytoskeleton, Development & Differentiation News [amp ] Views Source Type: research
Friend and foe, HNRNPC takes on immunostimulatory RNAs in breast cancer cells
The RNA-binding protein HNRNPC is highly expressed in breast cancer, but its contribution to tumorigenesis was unclear. In this issue, Wu et al (2018) demonstrate that elevated HNRNPC is essential for the proliferative ability of two breast cancer cell lines. Reducing HNRNPC results in the accumulation of short Alu-derived dsRNAs that bind RNA receptor RIG-I and stimulate the production of IFN, a cytokine with known antiproliferative activity. (Source: EMBO Journal)
Source: EMBO Journal - December 3, 2018 Category: Molecular Biology Authors: Sarbanes, S. L., Le Pen, J., Rice, C. M. Tags: Cancer, Immunology News [amp ] Views Source Type: research
Decapping enzymes STOP "cancer" ribosomes in their tracks
The production of ribosomes plays a central role in regulating cell cycle progression and cancer proliferation. A new study by Gaviraghi et al (2018) shows that mRNA decapping coactivator PNRC1 acts as a tumor suppressor by regulating ribosome biogenesis. PNRC1 relocalizes the Dcp1/Dcp2 mRNA decapping complex to the nucleolus and promotes decapping of specific snoRNAs to disrupt the processing of ribosomal RNA. By slowing rRNA processing, and thus ribosome biogenesis, PNRC1 acts as a gatekeeper that restrains oncogenic potential. (Source: EMBO Journal)
Source: EMBO Journal - December 3, 2018 Category: Molecular Biology Authors: Mugridge, J. S., Gross, J. D. Tags: Cancer, RNA Biology News [amp ] Views Source Type: research
Loss of tubulin deglutamylase CCP1 causes infantile-onset neurodegeneration
A set of glutamylases and deglutamylases controls levels of tubulin polyglutamylation, a prominent post-translational modification of neuronal microtubules. Defective tubulin polyglutamylation was first linked to neurodegeneration in the Purkinje cell degeneration (pcd) mouse, which lacks deglutamylase CCP1, displays massive cerebellar atrophy, and accumulates abnormally glutamylated tubulin in degenerating neurons. We found biallelic rare and damaging variants in the gene encoding CCP1 in 13 individuals with infantile-onset neurodegeneration and confirmed the absence of functional CCP1 along with dysregulated tubulin poly...
Source: EMBO Journal - December 3, 2018 Category: Molecular Biology Authors: Shashi, V., Magiera, M. M., Klein, D., Zaki, M., Schoch, K., Rudnik-Schöneborn, S., Norman, A., Lopes Abath Neto, O., Dusl, M., Yuan, X., Bartesaghi, L., De Marco, P., Alfares, A. A., Marom, R., Arold, S. T., Guzman-Vega, F. J., Pena, L. D., Smith Tags: Molecular Biology of Disease, Neuroscience Articles Source Type: research
Excessive tubulin polyglutamylation causes neurodegeneration and perturbs neuronal transport
Posttranslational modifications of tubulin are emerging regulators of microtubule functions. We have shown earlier that upregulated polyglutamylation is linked to rapid degeneration of Purkinje cells in mice with a mutation in the deglutamylating enzyme CCP1. How polyglutamylation leads to degeneration, whether it affects multiple neuron types, or which physiological processes it regulates in healthy neurons has remained unknown. Here, we demonstrate that excessive polyglutamylation induces neurodegeneration in a cell-autonomous manner and can occur in many parts of the central nervous system. Degeneration of selected neur...
Source: EMBO Journal - December 3, 2018 Category: Molecular Biology Authors: Magiera, M. M., Bodakuntla, S., Ziak, J., Lacomme, S., Marques Sousa, P., Leboucher, S., Hausrat, T. J., Bosc, C., Andrieux, A., Kneussel, M., Landry, M., Calas, A., Balastik, M., Janke, C. Tags: Cell Adhesion, Polarity & Cytoskeleton, Neuroscience, Post-translational Modifications, Proteolysis & Proteomics Articles Source Type: research
Downregulation of basal myosin-II is required for cell shape changes and tissue invagination
Tissue invagination drives embryo remodeling and assembly of internal organs during animal development. While the role of actomyosin-mediated apical constriction in initiating inward folding is well established, computational models suggest relaxation of the basal surface as an additional requirement. However, the lack of genetic mutations interfering specifically with basal relaxation has made it difficult to test its requirement during invagination so far. Here we use optogenetics to quantitatively control myosin-II levels at the basal surface of invaginating cells during Drosophila gastrulation. We show that while basal...
Source: EMBO Journal - December 3, 2018 Category: Molecular Biology Authors: Krueger, D., Tardivo, P., Nguyen, C., De Renzis, S. Tags: Cell Adhesion, Polarity & Cytoskeleton, Development & Differentiation Articles Source Type: research
Synergistic recruitment of UbcH7~Ub and phosphorylated Ubl domain triggers parkin activation
We present a model of an E2~Ub conjugate bound to the phospho-ubiquitin-loaded C-terminus of parkin, derived from NMR chemical shift perturbation experiments. We show the UbcH7~Ub conjugate binds in the open state whereby conjugated ubiquitin binds to the RING1/IBR interface. Further, NMR and mass spectrometry experiments indicate the RING0/RING2 interface is re-modelled, remote from the E2 binding site, and this alters the reactivity of the RING2(Rcat) catalytic cysteine, needed for ubiquitin transfer. Our experiments provide evidence that parkin phosphorylation and E2~Ub recruitment act synergistically to enhance a ...
Source: EMBO Journal - December 3, 2018 Category: Molecular Biology Authors: Condos, T. E., Dunkerley, K. M., Freeman, E. A., Barber, K. R., Aguirre, J. D., Chaugule, V. K., Xiao, Y., Konermann, L., Walden, H., Shaw, G. S. Tags: Post-translational Modifications, Proteolysis & Proteomics, Structural Biology Articles Source Type: research
PIF4-induced BR synthesis is critical to diurnal and thermomorphogenic growth
The Arabidopsis PIF4 and BES1/BZR1 transcription factors antagonize light signaling by facilitating co-activated expression of a large number of cell wall-loosening and auxin-related genes. While PIF4 directly activates expression of these targets, BES1 and BZR1 activity switch from a repressive to an activator function, depending on interaction with TOPLESS and other families of regulators including PIFs. However, the complexity of this regulation and its role in diurnal control of plant growth and brassinosteroid (BR) levels is little understood. We show by using a protein array that BES1, PIF4, and the BES1-PIF4 complex...
Source: EMBO Journal - December 3, 2018 Category: Molecular Biology Authors: Martinez, C., Espinosa-Ruiz, A., de Lucas, M., Bernardo-Garcia, S., Franco-Zorrilla, J. M., Prat, S. Tags: Plant Biology, Signal Transduction, Transcription Articles Source Type: research
