Journal of Molecular Cell Biology

The Muscle RING-finger protein-1 (MuRF1) is an E3 ubiquitin ligase expressed in skeletal and cardiac muscle tissues and it plays important roles in muscle remodeling. Upregulation of MuRF1 gene transcription participates in skeletal muscle atrophy, on contrary downregulation of protein expression leads to cardiac hypertrophy. MuRF1 gene point mutations have been found to generate protein aggregate myopathies (PAMs) defined as muscle disorder characterized by protein accumulation in muscle fibers. We have discovered that MuRF1 turned out to be also a target for a new post-translational modification arbitrated by conjugation of SUMO-1 and it is mediated by the SUMO ligases E2 UBC9 and the E3 PIASγ/4...

No abstract text is available yet for this article.

Class II HDACs, such as HDAC4, are critical regulators of the immune response in various immune cells; however, its role in innate immunity remains largely unknown. Here, we report that the overexpression of HDAC4 suppresses the production of type I interferons triggered by pattern-recognition receptors (PRRs). HDAC4 repressed the translocation of transcription factor IRF3 to the nucleus, thereby decreasing IRF3-mediated IFN-β expression. In particular, we also determined that HDAC4 can be phosphorylated and simultaneously block the phosphorylation of IRF3 at Ser386 and Ser396 by TBK1 and IKKε, respectively, by interacting with the kinase domain of TBK1 and IKKε...

The chromokinesin Kif4A controls proper chromosome condensation, congression/alignment, and cytokinesis to ensure faithful genetic inheritance. Here, we report that Cdk phosphorylation of human Kif4A at T1161 licenses Kif4A chromosomal localization, which, in turn, controls Kif4A early mitotic function. Phosphorylated Kif4A (Kif4AWT) or Cdk phospho-mimetic Kif4A mutant (Kif4ATE) associated with chromosomes and condensin I (non-SMC subunit CAP-G and core subunit SMC2) to regulate chromosome condensation, spindle morphology, and chromosome congression/alignment in early mitosis...

Fat mass and obesity-associated (FTO) protein is a ferrous ion (Fe2+)/2-oxoglutarate (2-OG)-dependent demethylase preferentially catalyzing m6A sites in RNA. The FTO gene is highly expressed in the hypothalamus with fluctuation in response to various nutritional conditions, which is believed to be involved in the control of whole body metabolism. However, the underlying mechanism in response to different nutritional cues remains poorly understood. Here we show that ketogenic diet-derived ketone body β-hydroxybutyrate (BHB) transiently increases FTO expression in both mouse hypothalamus and cultured cells...

Hair follicle dermal sheath (DS) harbors hair follicle dermal stem cells (hfDSCs), which can be recruited to replenish DS and dermal papilla (DP). Cultured DS cells can differentiate into various cell lineages in vitro. However, it is unclear how its plasticity is modulated in vivo. Wnt/β-catenin signaling plays an important role in maintaining stem cells of various lineages and is required for HF development and regeneration. Here we report that activation of β-catenin in DS generates ectopic HF outgrowth (EF) by reprogramming HF epidermal cells and DS cells themselves, and endows DS cells with hair inducing ability...

Metabotropic glutamate receptors are expressed at excitatory synapses and control synaptic transmission in mammalian brain. These receptors are involved in numerous patho-physiological functions. However, little is known about the molecular determinants responsible for their intracellular transport and membrane targeting. Here we investigated the nature of the molecular motor and adaptor protein responsible for trafficking and membrane localization of the group I metabotropic glutamate mGlu1 post-synaptic receptor in cultured hippocampal neurons...

Secretoneurin (SN) is a neuropeptide derived from specific proteolytic processing of the precursor secretogranin II (SgII). In zebrafish and other teleosts, there are two paralogs named sgIIa and sgIIb. Our results showed that neurons expressing sgIIb were aligned with central arteries in the hindbrain, demonstrating a close neurovascular association. Both sgIIb-/- and sgIIa-/-/sgIIb-/- mutant embryos were defective in hindbrain central artery development due to impairment of migration and proliferation of central artery cells...

Serine/arginine (SR)-rich proteins are critical for the regulation of alternative splicing (AS), which generates multiple mRNA isoforms from one gene and provides protein diversity for cell differentiation and tissue development. Genetic evidence suggests that Drosophila genital-specific overexpression of SR-related nuclear matrix protein of 160 kDa (SRm160), an SR protein with a PWI RNA-binding motif, causes defective development only in male flies and results in abnormal male genital structures and abnormal testis...

Glycosphingolipid (GSL) metabolism is involved in various physiological processes, including all major cell signaling pathways, and its dysregulation is linked to some diseases. The four-phosphate adaptor protein FAPP2-mediated glucosylceramide (GlcCer) transport for complex GSL synthesis has been studied extensively. However, the molecular machinery of FAPP2 as a GlcCer-transferring protein remains poorly defined. Here, we identified a Golgi-resident protein, acyl-coenzyme A binding domain containing 3 (ACBD3), as an interacting partner of FAPP2...

Lysine-specific demethylase 1 (LSD1) was the first histone demethylase identified as catalysing the removal of mono- and di-methylation marks on histone H3-K4. Despite the potential broad action of LSD1 in transcription regulation, recent studies indicate that LSD1 may coordinate with multiple epigenetic regulatory complexes including CoREST/HDAC complex, NuRD complex, SIRT1, and PRC2, implying complicated mechanistic actions of this seemingly simple enzyme. Here, we report that LSD1 is also an integral component of the SIN3A/HDAC complex...

Infertility is a severe public health problem worldwide that prevails up to 15% in reproductive-age couples, and male infertility accounts for half of total infertility. Studies on genetically modified animal models have identified lots of genes involved in the pathogenesis of male infertility. The underlying causes, however, remain largely unclear. In this study, we provide evidence that EMC10, one subunit of endoplasmic reticulum (ER) membrane protein complex (EMC), is required for male fertility. EMC10 is significantly decreased in spermatozoa from patients with asthenozoospermia and positively associated with human sperm motility...

No abstract text is available yet for this article.

Myogenesis is a complex process required for skeletal muscle formation during embryonic development and for regeneration and growth of myofibers in adults. Accumulating evidence suggests that long non-coding RNAs (lncRNAs) play key roles in regulating cell fate decision and function in various tissues. However, the role of lncRNAs in the regulation of myogenesis remains poorly understood. In this study, we identified a novel muscle-enriched lncRNA called 'Myolinc (AK142388)', which we functionally characterized in the C2C12 myoblast cell line...

Apoptosis and hypertrophy of cardiomyocytes are the primary causes of heart failure (HF), a global leading cause of death, and are regulated through the complicated intracellular signaling network, limiting the development of effective treatments due to its complexity. To identify effective therapeutic strategies for HF at a system level, we develop a large-scale comprehensive mathematical model of the cardiac signaling network by integrating all available experimental evidence. Attractor landscape analysis of the network model identifies distinct sets of control nodes that effectively suppress apoptosis and hypertrophy of cardiomyocytes under ischemic or pressure overload-induced HF, the two major types of HF...

The generation of induced pluripotent stem cells (iPSCs) offers a great opportunity in research and regenerative medicine. The current poor efficiency and incomplete mechanistic understanding of the reprogramming process hampers the clinical application of iPSCs. MeCP2 connects histone modification and DNA methylation, which are key changes of somatic cell reprogramming. However, the role of MeCP2 in cell reprogramming has not been examined. In this study, we found that MeCP2 deficiency enhanced reprogramming efficiency and stimulated cell proliferation through regulating cell cycle protein expression in the early stage of reprogramming...

No abstract text is available yet for this article.

Clinical therapies of pluripotent stem cells (PSCs)-based transplantation have been hindered by frequent development of teratomas or tumors in animal models and clinical patients. Therefore, clarifying the mechanism of carcinogenesis in stem cell therapy is of great importance for reducing the risk of tumorigenicity. Here we differentiate Oct4-GFP mouse embryonic stem cells (mESCs) into neural progenitor cells (NPCs) and find that a minority of Oct4+ cells are continuously sustained at Oct4+ state. These cells can be enriched and proliferated in a standard ESC medium...

NF-κB signaling controls a large set of physiological processes ranging from inflammatory responses to cell death. Its activation is tightly regulated through controlling the activity and stability of multiple signaling components. Here, we identify that NF-κB activation is suppressed by an F-box protein, S-phase kinase associated protein 2 (SKP2). SKP2 deficiency enhanced NF-κB activation as well as the production of inflammatory cytokines. In addition, SKP2 potently blocked the NF-κB activation at the IκB kinase (IKK) level...

No abstract text is available yet for this article.