CryoEM of Tropomyosin-receptor kinase fused gene protein (TRK-fused gene protein; TFG) Low Complexity Domain (residues 237-327) P285L mutant, amyloid fibers
Ontology highlight
ABSTRACT:
SUBMITTER: David Eisenberg
PROVIDER: EMPIAR-11930 | biostudies-other |
REPOSITORIES: biostudies-other
Publications
Fibril structures of TFG protein mutants validate the identification of TFG as a disease-related amyloid protein by the IMPAcT method.
Rosenberg Gregory M GM Abskharon Romany R Boyer David R DR Ge Peng P Sawaya Michael R MR Eisenberg David S DS
PNAS nexus 20231120 12
We previously presented a bioinformatic method for identifying diseases that arise from a mutation in a protein's low-complexity domain that drives the protein into pathogenic amyloid fibrils. One protein so identified was the tropomyosin-receptor kinase-fused gene protein (TRK-fused gene protein or TFG). Mutations in TFG are associated with degenerative neurological conditions. Here, we present experimental evidence that confirms our prediction that these conditions are amyloid-related. We find ...[more]
Similar Datasets
Project description: Not available
| EMPIAR-11929 | biostudies-other
Project description:The TRK-fused gene (TFG) was originally identified in chromosome translocation events, creating a pair of oncogenes in some cancers, and was recently demonstrated as the causal gene of hereditary motor and sensory neuropathy with proximal dominant involvement. Recently, we cloned an alternative splicing variant of Tfg from a cDNA library of the rat retina, tentatively naming it retinal Tfg (rTfg). Although the common form of Tfg is ubiquitously expressed in most rat tissues, rTfg expression is localized to the central nervous system. In this study, we produced an antibody against an rTFG-specific amino acid sequence and used it to examine the localization of rTFG-like protein in the rat retina by immunohistochemistry and Western blots. Western blot analysis showed that the antibody detected a single band of 24 kDa in the rat retina. When we examined rTFG recombinant protein, the antibody detected two bands of about 42 kDa and 24 kDa. The results suggest that the 24 kDa rTFG-like protein is a fragment of rTFG. In our immunohistochemical studies of the rat retina, rTFG-like immunoreactivity was observed in all calbindin D-28K-positive horizontal cells and in some syntaxin 1-positive amacrine cells (ACs). In addition, the rTFG-like immunopositive ACs were actually glycine transporter 1-positive glycinergic or glutamate decarboxylase-positive GABAergic ACs. Our findings indicate that this novel 24 kDa rTFG-like protein may play a specific role in retinal inhibitory interneurons.
| S-EPMC4138404 | biostudies-literature
Project description:The TRK-fused gene (TFG in human, Tfg in rat) was originally identified in human papillary thyroid cancer as a chimeric form of the NTRK1 gene. It was since reported that the gene product (TFG) plays a role in regulating phosphotyrosine-specific phosphatase-1 activity. As shown in the accompanying paper, we produced an antibody to rat TFG and used it to localize TFG to selected neurons in specific regions. In the present study, we mapped the TFG-positive neurons in the brainstem, cerebellum, and spinal cord of rats. In the brainstem, neurons intensely positive for TFG were distributed in the raphe nuclei, the gigantocellular reticular nucleus, the reticulotegmental nucleus of the pons, and some cranial nerve nuclei such as the trigeminal nuclei, the vestibulocochlear nuclei, and the dorsal motor nucleus of the vagus. Purkinje cells in the cerebellum and motor neurons in the spinal anterior horn were also positive for TFG. These results provide fundamental data for studying the functions of TFG in the brain.
| S-EPMC3317492 | biostudies-literature
Project description:hnRNPA2 is a human ribonucleoprotein (RNP) involved in RNA metabolism. It forms fibrils both under cellular stress and in mutated form in neurodegenerative conditions. Previous work established that the C-terminal low-complexity domain (LCD) of hnRNPA2 fibrillizes under stress, and missense mutations in this domain are found in the disease multisystem proteinopathy (MSP). However, little is known at the atomic level about the hnRNPA2 LCD structure that is involved in those processes and how disease mutations cause structural change. Here we present the cryo-electron microscopy (cryoEM) structure of the hnRNPA2 LCD fibril core and demonstrate its capability to form a reversible hydrogel in vitro containing amyloid-like fibrils. Whereas these fibrils, like pathogenic amyloid, are formed from protein chains stacked into β-sheets by backbone hydrogen bonds, they display distinct structural differences: the chains are kinked, enabling non-covalent cross-linking of fibrils and disfavoring formation of pathogenic steric zippers. Both reversibility and energetic calculations suggest these fibrils are less stable than pathogenic amyloid. Moreover, the crystal structure of the disease-mutation-containing segment (D290V) of hnRNPA2 suggests that the replacement fundamentally alters the fibril structure to a more stable energetic state. These findings illuminate how molecular interactions promote protein fibril networks and how mutation can transform fibril structure from functional to a pathogenic form.
| S-EPMC7427792 | biostudies-literature
Project description:Antiviral innate immune response to RNA virus infection is supported by Pattern-Recognition Receptors (PRR) including RIG-I-Like Receptors (RLR), which lead to type I interferons (IFNs) and IFN-stimulated genes (ISG) production. Upon sensing of viral RNA, the E3 ubiquitin ligase TNF Receptor-Associated Factor-3 (TRAF3) is recruited along with its substrate TANK-Binding Kinase (TBK1), to MAVS-containing subcellular compartments, including mitochondria, peroxisomes, and the mitochondria-associated endoplasmic reticulum membrane (MAM). However, the regulation of such events remains largely unresolved. Here, we identify TRK-Fused Gene (TFG), a protein involved in the transport of newly synthesized proteins to the endomembrane system via the Coat Protein complex II (COPII) transport vesicles, as a new TRAF3-interacting protein allowing the efficient recruitment of TRAF3 to MAVS and TBK1 following Sendai virus (SeV) infection. Using siRNA and shRNA approaches, we show that TFG is required for virus-induced TBK1 activation resulting in C-terminal IRF3 phosphorylation and dimerization. We further show that the ability of the TRAF3-TFG complex to engage mTOR following SeV infection allows TBK1 to phosphorylate mTOR on serine 2159, a post-translational modification shown to promote mTORC1 signaling. We demonstrate that the activation of mTORC1 signaling during SeV infection plays a positive role in the expression of Viperin, IRF7 and IFN-induced proteins with tetratricopeptide repeats (IFITs) proteins, and that depleting TFG resulted in a compromised antiviral state. Our study, therefore, identifies TFG as an essential component of the RLR-dependent type I IFN antiviral response.
| S-EPMC7790228 | biostudies-literature
Project description:The Trk-fused gene (TFG) is reportedly involved in the process of COPII-mediated vesicle transport and missense mutations in TFG cause several neurodegenerative diseases including hereditary motor and sensory neuropathy with proximal dominant involvement (HMSN-P). The high coincidence ratio between HMSN-P and diabetes mellitus suggests TFG to have an important role(s) in glucose homeostasis. To examine this possibility, β-cell specific TFG knockout mice (βTFG KO) were generated. Interestingly, βTFG KO displayed marked glucose intolerance with reduced insulin secretion. Immunohistochemical analysis revealed smaller β-cell masses in βTFG KO than in controls, likely attributable to diminished β-cell proliferation. Consistently, β-cell expansion in response to a high-fat, high-sucrose (HFHS) diet was significantly impaired in βTFG KO. Furthermore, glucose-induced insulin secretion was also markedly impaired in islets isolated from βTFG KO. Electron microscopic observation revealed endoplasmic reticulum (ER) dilatation, suggestive of ER stress, and smaller insulin crystal diameters in β-cells of βTFG KO. Microarray gene expression analysis indicated downregulation of NF-E2 related factor 2 (Nrf2) and its downstream genes in TFG depleted islets. Collectively, TFG in pancreatic β-cells plays a vital role in maintaining both the mass and function of β-cells, and its dysfunction increases the tendency to develop glucose intolerance.
| S-EPMC5638802 | biostudies-literature
Project description:The tropomyosin receptor kinases family (TrkA, TrkB, and TrkC) supports neuronal growth, survival, and differentiation during development, adult life, and aging. TrkA/B/C downregulation is a prominent hallmark of various neurological disorders including Alzheimer's disease (AD). Abnormally expressed or overexpressed full-length or oncogenic fusion TrkA/B/C proteins were shown to drive tumorigenesis in a variety of neurogenic and non-neurogenic human cancers and are currently the focus of intensive clinical research. Neurologic and oncologic studies of the spatiotemporal alterations in TrkA/B/C expression and density and the determination of target engagement of emerging antineoplastic clinical inhibitors in normal and diseased tissue are crucially needed but have remained largely unexplored due to the lack of suitable non-invasive probes. Here, we review the recent development of carbon-11- and fluorine-18-labeled positron emission tomography (PET) radioligands based on specifically designed small molecule kinase catalytic domain-binding inhibitors of TrkA/B/C. Basic developments in medicinal chemistry, radiolabeling and translational PET imaging in multiple species including humans are highlighted.
| S-EPMC6469173 | biostudies-literature
Project description:The endoplasmic reticulum (ER) is an organelle in which important cellular events such as protein synthesis and lipid production occur. Although many lipid molecules are produced in the ER, the effect of ER-organizing proteins on lipid synthesis in sebocytes has not been completely elucidated. Tropomyosin-receptor kinase fused gene (TFG) is located in ER exit sites and participates in COPII-coated vesicle formation along with many scaffold proteins, such as Sec. 13 and Sec. 16. In this study, we investigated the putative role of TFG in lipid production in sebocytes using an immortalized human sebocyte line. During IGF-1-induced lipogenesis, the level of the TFG protein was increased in a time- and dose-dependent manner. When TFG was over-expressed using recombinant adenovirus, lipid production in sebocytes was increased along with an up-regulation of the expression of lipogenic regulators, such as PPAR-γ, SREBP-1 and SCD. Conversely, down-regulation of TFG using a microRNA (miR) decreased lipid production and the expression of lipogenic regulators. Based on these data, TFG is a novel regulator of lipid synthesis in sebocytes.
| S-EPMC6488642 | biostudies-literature
Project description:The TRK-fused gene (TFG in human, Tfg in rat) was originally identified in human papillary thyroid cancer as a chimeric form of the NTRK1 gene. It has been reported that the gene product (TFG) plays a role in regulating phosphotyrosine-specific phosphatase-1 activity. However, no information regarding the localization of Tfg in rat tissues is available. In this study, we investigated the expression of Tfg mRNA in normal rat tissues using reverse transcription-polymerase chain reaction (RT-PCR). We also produced an antibody against Tfg gene products and examined the localization of TFG in the rat brain and retina. The RT-PCR experiments demonstrated that two types of Tfg mRNA were expressed in rat tissues: the conventional form of Tfg (cTfg) and a novel variant form, retinal Tfg (rTfg). RT-PCR analyses demonstrated that cTfg was ubiquitously expressed in rat tissues, while rTfg was predominantly expressed in the brain and retina. Western blot analysis demonstrated two bands with molecular weights of about 30 kDa and 50 kDa in the rat brain. Immunohistochemistry indicated that TFG proteins were predominantly expressed by neurons in the brain. In the rat retina, intense TFG-immunoreactivity was detected in the layer of rods and cones and the outer plexiform layer.
| S-EPMC3317498 | biostudies-literature
Project description:NTRK gene fusions affecting the tropomyosin receptor kinase (TRK) protein family have been found to be oncogenic drivers in a broad range of cancers. Small molecule inhibitors targeting TRK activity, such as the recently Food and Drug Administration-approved agent larotrectinib (Vitrakvi®), have shown promising efficacy and safety data in the treatment of patients with TRK fusion cancers. NTRK gene fusions can be detected using several different approaches, including fluorescent in situ hybridization, reverse transcription polymerase chain reaction, immunohistochemistry, next-generation sequencing, and ribonucleic acid-based multiplexed assays. Identifying patients with cancers that harbor NTRK gene fusions will optimize treatment outcomes by providing targeted precision therapy.
| S-EPMC7297824 | biostudies-literature