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Kobayashi N, Katayama R, Minamoto K, Kawaguchi T, Tani S. C-terminus of serine-arginine protein kinase-like protein, SrpkF, is involved in conidiophore formation and hyphal growth under salt stress in Aspergillus aculeatus. Int Microbiol 2024; 27:91-100. [PMID: 37195349 DOI: 10.1007/s10123-023-00373-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 04/28/2023] [Accepted: 05/09/2023] [Indexed: 05/18/2023]
Abstract
The serine-arginine protein kinase-like protein, SrpkF, was identified as a regulator for the cellulose-responsive induction of cellulase genes in Aspergillus aculeatus. To analyze various aspects of SrpkF function, we examined the growth of the control strain (MR12); C-terminus deletion mutant, which produced SrpkF1-327 (ΔCsrpkF); whole gene-deletion mutant of srpkF (ΔsrpkF), srpkF overexpressing strain (OEsprkF); and the complemented strain (srpkF+) under various stress conditions. All test strains grew normally on minimal medium under control, high salt (1.5 M KCl), and high osmolality (2.0 M sorbitol and 1.0 M sucrose). However, only ΔCsrpkF showed reduced conidiation on 1.0 M NaCl media. Conidiation of ΔCsrpkF on 1.0 M NaCl media was reduced to 12% compared with that of srpkF+. Further, when OEsprkF and ΔCsrpkF were pre-cultured under salt stress conditions, germination under salt stress conditions was enhanced in both strains. By contrast, deletion of srpkF did not affect hyphal growth and conidiation under the same conditions. We then quantified the transcripts of the regulators involved in the central asexual conidiation pathway in A. aculeatus. The findings revealed that the expression of brlA, abaA, wetA, and vosA was reduced in ΔCsrpkF under salt stress. These data suggest that in A. aculeatus, SrpkF regulates conidiophore development. The C-terminus of SrpkF seems to be important for regulating SrpkF function in response to culture conditions such as salt stress.
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Affiliation(s)
- Natsumi Kobayashi
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, 599-8531, Japan
| | - Ryohei Katayama
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, 599-8531, Japan
| | - Kentaro Minamoto
- Graduate School of Agriculture, Osaka Metropolitan University, 1-1 Gakuen-cho, Sakai, 599-8531, Japan
| | - Takashi Kawaguchi
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, 599-8531, Japan
- Graduate School of Agriculture, Osaka Metropolitan University, 1-1 Gakuen-cho, Sakai, 599-8531, Japan
| | - Shuji Tani
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, 599-8531, Japan.
- Graduate School of Agriculture, Osaka Metropolitan University, 1-1 Gakuen-cho, Sakai, 599-8531, Japan.
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2
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Hogg EKJ, Findlay GM. Functions of SRPK, CLK and DYRK kinases in stem cells, development, and human developmental disorders. FEBS Lett 2023; 597:2375-2415. [PMID: 37607329 PMCID: PMC10952393 DOI: 10.1002/1873-3468.14723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 07/08/2023] [Accepted: 07/18/2023] [Indexed: 08/24/2023]
Abstract
Human developmental disorders encompass a wide range of debilitating physical conditions and intellectual disabilities. Perturbation of protein kinase signalling underlies the development of some of these disorders. For example, disrupted SRPK signalling is associated with intellectual disabilities, and the gene dosage of DYRKs can dictate the pathology of disorders including Down's syndrome. Here, we review the emerging roles of the CMGC kinase families SRPK, CLK, DYRK, and sub-family HIPK during embryonic development and in developmental disorders. In particular, SRPK, CLK, and DYRK kinase families have key roles in developmental signalling and stem cell regulation, and can co-ordinate neuronal development and function. Genetic studies in model organisms reveal critical phenotypes including embryonic lethality, sterility, musculoskeletal errors, and most notably, altered neurological behaviours arising from defects of the neuroectoderm and altered neuronal signalling. Further unpicking the mechanisms of specific kinases using human stem cell models of neuronal differentiation and function will improve our understanding of human developmental disorders and may provide avenues for therapeutic strategies.
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Affiliation(s)
- Elizabeth K. J. Hogg
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life SciencesUniversity of DundeeUK
| | - Greg M. Findlay
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life SciencesUniversity of DundeeUK
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3
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Ghosh A, Chakraborty P, Biswas D. Fine tuning of the transcription juggernaut: A sweet and sour saga of acetylation and ubiquitination. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2023; 1866:194944. [PMID: 37236503 DOI: 10.1016/j.bbagrm.2023.194944] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 04/26/2023] [Accepted: 05/18/2023] [Indexed: 05/28/2023]
Abstract
Among post-translational modifications of proteins, acetylation, phosphorylation, and ubiquitination are most extensively studied over the last several decades. Owing to their different target residues for modifications, cross-talk between phosphorylation with that of acetylation and ubiquitination is relatively less pronounced. However, since canonical acetylation and ubiquitination happen only on the lysine residues, an overlap of the same lysine residue being targeted for both acetylation and ubiquitination happens quite frequently and thus plays key roles in overall functional regulation predominantly through modulation of protein stability. In this review, we discuss the cross-talk of acetylation and ubiquitination in the regulation of protein stability for the functional regulation of cellular processes with an emphasis on transcriptional regulation. Further, we emphasize our understanding of the functional regulation of Super Elongation Complex (SEC)-mediated transcription, through regulation of stabilization by acetylation, deacetylation and ubiquitination and associated enzymes and its implication in human diseases.
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Affiliation(s)
- Avik Ghosh
- Laboratory of Transcription Biology Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 32, India
| | - Poushali Chakraborty
- Laboratory of Transcription Biology Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 32, India
| | - Debabrata Biswas
- Laboratory of Transcription Biology Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 32, India.
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4
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SR Protein Kinase 1 Inhibition by TAF15. Cells 2022; 12:cells12010126. [PMID: 36611919 PMCID: PMC9818988 DOI: 10.3390/cells12010126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/21/2022] [Accepted: 12/24/2022] [Indexed: 12/29/2022] Open
Abstract
Although SRPKs were discovered nearly 30 years ago, our understanding of their mode of regulation is still limited. Regarded as constitutively active enzymes known to participate in diverse biological processes, their prominent mode of regulation mainly depends on their intracellular localization. Molecular chaperones associate with a large internal spacer sequence that separates the bipartite kinase catalytic core and modulates the kinases' partitioning between the cytoplasm and nucleus. Besides molecular chaperones that function as anchoring proteins, a few other proteins were shown to interact directly with SRPK1, the most-studied member of SRPKs, and alter its activity. In this study, we identified TAF15, which has been involved in transcription initiation, splicing, DNA repair, and RNA maturation, as a novel SRPK1-interacting protein. The C-terminal RGG domain of TAF15 was able to associate with SRPK1 and downregulate its activity. Furthermore, overexpression of this domain partially relocalized SRPK1 to the nucleus and resulted in hypophosphorylation of SR proteins, inhibition of splicing of a reporter minigene, and inhibition of Lamin B receptor phosphorylation. We further demonstrated that peptides comprising the RGG repeats of nucleolin, HNRPU, and HNRNPA2B1, were also able to inhibit SRPK1 activity, suggesting that negative regulation of SRPK1 activity might be a key biochemical property of RGG motif-containing proteins.
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5
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Targeting Protein Kinases and Epigenetic Control as Combinatorial Therapy Options for Advanced Prostate Cancer Treatment. Pharmaceutics 2022; 14:pharmaceutics14030515. [PMID: 35335890 PMCID: PMC8949110 DOI: 10.3390/pharmaceutics14030515] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Revised: 02/15/2022] [Accepted: 02/21/2022] [Indexed: 02/02/2023] Open
Abstract
Prostate cancer (PC), the fifth leading cause of cancer-related mortality worldwide, is known as metastatic bone cancer when it spreads to the bone. Although there is still no effective treatment for advanced/metastatic PC, awareness of the molecular events that contribute to PC progression has opened up opportunities and raised hopes for the development of new treatment strategies. Androgen deprivation and androgen-receptor-targeting therapies are two gold standard treatments for metastatic PC. However, acquired resistance to these treatments is a crucial challenge. Due to the role of protein kinases (PKs) in the growth, proliferation, and metastases of prostatic tumors, combinatorial therapy by PK inhibitors may help pave the way for metastatic PC treatment. Additionally, PC is known to have epigenetic involvement. Thus, understanding epigenetic pathways can help adopt another combinatorial treatment strategy. In this study, we reviewed the PKs that promote PC to advanced stages. We also summarized some PK inhibitors that may be used to treat advanced PC and we discussed the importance of epigenetic control in this cancer. We hope the information presented in this article will contribute to finding an effective treatment for the management of advanced PC.
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6
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Bustos F, Segarra-Fas A, Nardocci G, Cassidy A, Antico O, Davidson L, Brandenburg L, Macartney TJ, Toth R, Hastie CJ, Moran J, Gourlay R, Varghese J, Soares RF, Montecino M, Findlay GM. Functional Diversification of SRSF Protein Kinase to Control Ubiquitin-Dependent Neurodevelopmental Signaling. Dev Cell 2020; 55:629-647.e7. [PMID: 33080171 PMCID: PMC7725506 DOI: 10.1016/j.devcel.2020.09.025] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 08/17/2020] [Accepted: 09/25/2020] [Indexed: 02/06/2023]
Abstract
Conserved protein kinases with core cellular functions have been frequently redeployed during metazoan evolution to regulate specialized developmental processes. The Ser/Arg (SR)-rich splicing factor (SRSF) protein kinase (SRPK), which is implicated in splicing regulation, is one such conserved eukaryotic kinase. Surprisingly, we show that SRPK has acquired the capacity to control a neurodevelopmental ubiquitin signaling pathway. In mammalian embryonic stem cells and cultured neurons, SRPK phosphorylates Ser-Arg motifs in RNF12/RLIM, a key developmental E3 ubiquitin ligase that is mutated in an intellectual disability syndrome. Processive phosphorylation by SRPK stimulates RNF12-dependent ubiquitylation of nuclear transcription factor substrates, thereby acting to restrain a neural gene expression program that is aberrantly expressed in intellectual disability. SRPK family genes are also mutated in intellectual disability disorders, and patient-derived SRPK point mutations impair RNF12 phosphorylation. Our data reveal unappreciated functional diversification of SRPK to regulate ubiquitin signaling that ensures correct regulation of neurodevelopmental gene expression.
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Affiliation(s)
- Francisco Bustos
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, the University of Dundee, Dundee DD1 5EH, UK
| | - Anna Segarra-Fas
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, the University of Dundee, Dundee DD1 5EH, UK
| | - Gino Nardocci
- Institute of Biomedical Sciences and FONDAP Center for Genome Regulation, Universidad Andrés Bello, Santiago, Chile
| | - Andrew Cassidy
- Tayside Centre for Genomic Analysis, School of Medicine, University of Dundee, Dundee DD1 9SY, UK
| | - Odetta Antico
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, the University of Dundee, Dundee DD1 5EH, UK
| | - Lindsay Davidson
- School of Life Sciences, The University of Dundee, Dundee DD1 5EH, UK
| | - Lennart Brandenburg
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, the University of Dundee, Dundee DD1 5EH, UK
| | - Thomas J Macartney
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, the University of Dundee, Dundee DD1 5EH, UK
| | - Rachel Toth
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, the University of Dundee, Dundee DD1 5EH, UK
| | - C James Hastie
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, the University of Dundee, Dundee DD1 5EH, UK
| | - Jennifer Moran
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, the University of Dundee, Dundee DD1 5EH, UK
| | - Robert Gourlay
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, the University of Dundee, Dundee DD1 5EH, UK
| | - Joby Varghese
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, the University of Dundee, Dundee DD1 5EH, UK
| | - Renata F Soares
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, the University of Dundee, Dundee DD1 5EH, UK
| | - Martin Montecino
- Institute of Biomedical Sciences and FONDAP Center for Genome Regulation, Universidad Andrés Bello, Santiago, Chile
| | - Greg M Findlay
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, the University of Dundee, Dundee DD1 5EH, UK.
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7
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Chandra A, Goyal N, Qamar I, Singh N. Identification of hot spot residues on serine-arginine protein kinase-1 by molecular dynamics simulation studies. J Biomol Struct Dyn 2020; 39:1579-1587. [DOI: 10.1080/07391102.2020.1734487] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Anshuman Chandra
- School of Biotechnology, Gautam Buddha University, Greater Noida, Uttar Pradesh, India
| | - Nainee Goyal
- School of Biotechnology, Gautam Buddha University, Greater Noida, Uttar Pradesh, India
| | - Imteyaz Qamar
- School of Biotechnology, Gautam Buddha University, Greater Noida, Uttar Pradesh, India
| | - Nagendra Singh
- School of Biotechnology, Gautam Buddha University, Greater Noida, Uttar Pradesh, India
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8
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Yeung W, Ruan Z, Kannan N. Emerging roles of the αC-β4 loop in protein kinase structure, function, evolution, and disease. IUBMB Life 2020; 72:1189-1202. [PMID: 32101380 DOI: 10.1002/iub.2253] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 02/07/2020] [Indexed: 12/11/2022]
Abstract
The faithful propagation of cellular signals in most organisms relies on the coordinated functions of a large family of protein kinases that share a conserved catalytic domain. The catalytic domain is a dynamic scaffold that undergoes large conformational changes upon activation. Most of these conformational changes, such as movement of the regulatory αC-helix from an "out" to "in" conformation, hinge on a conserved, but understudied, loop termed the αC-β4 loop, which mediates conserved interactions to tether flexible structural elements to the kinase core. We previously showed that the αC-β4 loop is a unique feature of eukaryotic protein kinases. Here, we review the emerging roles of this loop in kinase structure, function, regulation, and diseases. Through a kinome-wide analysis, we define the boundaries of the loop for the first time and show that sequence and structural variation in the loop correlate with conformational and regulatory variation. Many recurrent disease mutations map to the αC-β4 loop and contribute to drug resistance and abnormal kinase activation by relieving key auto-inhibitory interactions associated with αC-helix and inter-lobe movement. The αC-β4 loop is a hotspot for post-translational modifications, protein-protein interaction, and Hsp90 mediated folding. Our kinome-wide analysis provides insights for hypothesis-driven characterization of understudied kinases and the development of allosteric protein kinase inhibitors.
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Affiliation(s)
- Wayland Yeung
- Institute of Bioinformatics, University of Georgia, Athens, Georgia
| | - Zheng Ruan
- Institute of Bioinformatics, University of Georgia, Athens, Georgia
| | - Natarajan Kannan
- Institute of Bioinformatics, University of Georgia, Athens, Georgia.,Department of Biochemistry & Molecular Biology, University of Georgia, Athens, Georgia
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9
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Tunnicliffe RB, Hu WK, Wu MY, Levy C, Mould AP, McKenzie EA, Sandri-Goldin RM, Golovanov AP. Molecular Mechanism of SR Protein Kinase 1 Inhibition by the Herpes Virus Protein ICP27. mBio 2019; 10:e02551-19. [PMID: 31641093 PMCID: PMC6805999 DOI: 10.1128/mbio.02551-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 09/30/2019] [Indexed: 12/11/2022] Open
Abstract
Serine-arginine (SR) protein kinase 1 (SRPK1) catalyzes the phosphorylation of SR proteins, which are a conserved family of splicing factors that contain a domain rich in arginine and serine repeats. SR proteins play important roles in constitutive pre-mRNA splicing and are also important regulators of alternative splicing. During herpes simplex virus infection, SRPK1 is inactivated and its cellular distribution is markedly altered by interaction with the viral protein ICP27, resulting in hypophosphorylation of SR proteins. Mutational analysis previously showed that the RGG box motif of ICP27 is required for interaction with SRPK1; however, the mechanism for the inhibition and the exact role of the RGG box was unknown. Here, we used solution nuclear magnetic resonance (NMR) spectroscopy and isothermal titration calorimetry (ITC) to demonstrate that the isolated peptide comprising the RGG box of ICP27 binds to SRPK1 with high affinity, competing with a native substrate, the SR repeat region of SR protein SRSF1. We determined the crystal structure of the complex between SRPK1 and an RGG box peptide, which revealed that the viral peptide binds to the substrate docking groove, mimicking the interactions of SR repeats. Site-directed mutagenesis within the RGG box further confirmed the importance of selected arginine residues for interaction, relocalization, and inhibition of SRPK1 in vivo Together these data reveal the molecular mechanism of the competitive inhibition of cellular SRPK1 by viral ICP27, which modulates SRPK1 activity.IMPORTANCE Serine arginine (SR) proteins are a family of mRNA regulatory proteins that can modulate spliceosome association with different splice sites and therefore regulate alternative splicing. Phosphorylation within SR proteins is necessary for splice-site recognition, and this is catalyzed by SR protein kinase 1 (SRPK1). The herpes simplex virus (HSV-1) protein ICP27 has been shown previously to interact with and downregulate SRPK1 activity in vivo; however, the molecular mechanism for this interaction and inhibition was unknown. Here, we demonstrate that the isolated peptide fragment of ICP27 containing RGG box binds to SRPK1 with high affinity, and competes with a native cellular substrate. Elucidation of the SRPK1-RGG box crystal structure further showed that a short palindromic RGRRRGR sequence binds in the substrate docking groove of SRPK1, mimicking the binding of SR repeats of substrates. These data reveal how the viral protein ICP27 inactivates SRPK1, promoting hypophosphorylation of proteins regulating splicing.
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Affiliation(s)
- Richard B Tunnicliffe
- Manchester Institute of Biotechnology and Department of Chemistry, Faculty of Science and Engineering, The University of Manchester, Manchester, United Kingdom
| | - William K Hu
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California, Irvine, California, USA
| | - Michele Y Wu
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California, Irvine, California, USA
| | - Colin Levy
- Manchester Institute of Biotechnology and Department of Chemistry, Faculty of Science and Engineering, The University of Manchester, Manchester, United Kingdom
| | - A Paul Mould
- Biomolecular Analysis Core Facility, Faculty of Biology, Medicine and Health, University of Manchester, United Kingdom
| | - Edward A McKenzie
- Manchester Institute of Biotechnology and Department of Chemistry, Faculty of Science and Engineering, The University of Manchester, Manchester, United Kingdom
| | - Rozanne M Sandri-Goldin
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California, Irvine, California, USA
| | - Alexander P Golovanov
- Manchester Institute of Biotechnology and Department of Chemistry, Faculty of Science and Engineering, The University of Manchester, Manchester, United Kingdom
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10
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Barbosa ÉDAA, Seraphim TV, Gandin CA, Teixeira LF, da Silva RAG, Righetto GL, Goncalves KDA, Vasconcellos RDS, Almeida MR, Silva Júnior A, Fietto JLR, Kobarg J, Gileadi C, Massirer KB, Borges JC, de Oliveira Neto M, Bressan GC. Insights into the full-length SRPK2 structure and its hydrodynamic behavior. Int J Biol Macromol 2019; 137:205-214. [PMID: 31229549 DOI: 10.1016/j.ijbiomac.2019.06.135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 06/04/2019] [Accepted: 06/19/2019] [Indexed: 11/30/2022]
Abstract
The serine/arginine-rich protein kinase 2 (SRPK2) has been reported as upregulated in several cancer types, with roles in hallmarks such as cell migration, growth, and apoptosis. These findings have indicated that SRPK2 is a promising emerging target in drug discovery initiatives. Although high-resolution models are available for SRPK2 (PDB 2X7G), they have been obtained with a heavily truncated recombinant protein version (~50% of the primary structure), due to the presence of long intrinsically unstructured regions. In the present work, we sought to characterize the structure of a full-length recombinant version of SRPK2 in solution. Low-resolution Small-Angle X-ray Scattering data were obtained for both versions of SRPK2. The truncated ΔNΔS-SRPK2 presented a propensity to dimerize at higher concentrations whereas the full-length SRPK2 was mainly found as dimers. The hydrodynamic behavior of the full-length SRPK2 was further investigated by analytical size exclusion chromatography and sedimentation velocity analytical ultracentrifugation experiments. SRPK2 behaved as a monomer-dimer equilibrium and both forms have an elongated shape in solution, pointing to a stretched-to-closed tendency among the conformational plasticity observed. Taken together, these findings allowed us to define unique structural features of the SRPK2 within SRPK family, characterized by its flexible regions outside the bipartite kinase domain.
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Affiliation(s)
| | | | - César Augusto Gandin
- Departamento de Física e Biofísica, Universidade Estadual Paulista, Botucatu, SP, Brazil
| | | | | | - Germanna L Righetto
- Departamento de Genética, Evolução, Microbiologia e Imunologia, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, SP, Brazil
| | - Kaliandra De Almeida Goncalves
- Departamento de Genética, Evolução, Microbiologia e Imunologia, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, SP, Brazil
| | | | - Márcia Rogéria Almeida
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | | | | | - Jörg Kobarg
- Instituto de Biologia, Departamento de Bioquímica e Biologia Tecidual e Faculdade de Ciências Farmacêuticas, Universidade Estadual de Campinas, Campinas, SP, Brazil
| | - Carina Gileadi
- Structural Genomics Consortium, Universidade Estadual de Campinas, Cidade Universitária Zeferino Vaz, Av. Dr. André Tosello, 550, Barão Geraldo, Campinas, SP, Brazil; Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Katlin B Massirer
- Structural Genomics Consortium, Universidade Estadual de Campinas, Cidade Universitária Zeferino Vaz, Av. Dr. André Tosello, 550, Barão Geraldo, Campinas, SP, Brazil; Center for Molecular Biology and Genetic Engineering, CBMEG, Universidade Estadual de Campinas, Campinas, SPUniversidade Estadual de Campinas, Campinas, Brazil
| | - Julio César Borges
- Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil
| | - Mario de Oliveira Neto
- Departamento de Física e Biofísica, Universidade Estadual Paulista, Botucatu, SP, Brazil
| | - Gustavo Costa Bressan
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Viçosa, MG, Brazil.
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11
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Patel M, Sachidanandan M, Adnan M. Serine arginine protein kinase 1 (SRPK1): a moonlighting protein with theranostic ability in cancer prevention. Mol Biol Rep 2018; 46:1487-1497. [PMID: 30535769 DOI: 10.1007/s11033-018-4545-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 11/30/2018] [Indexed: 12/15/2022]
Abstract
Serine/arginine protein kinase 1 (SRPK1); a versatile functional moonlighting protein involved in varied cellular activities comprised of cell cycle progression, innate immune response, chromatin reorganization, negative and positive regulation of viral genome replication, protein amino acid phosphorylation, regulation of numerous mRNA-processing pathways, germ cell development as well as inflammation due to acquaintances with many transcription factors and signaling pathways. Several diseases including cancer have been associated with dysregulation of SRPK1. The function of SRPK1 in cancer is contradictory and inexplicable because it acts as both tumor suppressor and promoter based on the type of cell and locale. Over expression of SRPK1 including its role has been recently narrated and associated with several cancers, which includes, lung, glioma, prostate and breast via dysregulated signals from the Akt/eIF4E/HIF-1/VEGF, Erk or MAPK, PI3K/AKT/mTOR, TGF-β, and Wnt/β-catenin signaling pathways. Therefore, SRPK1 has occurred as a promising and possible curative target in cancer. In recent years, few natural and synthetic SRPK1 inhibitors have been discovered. This review emphasizes and highlights the complicated connections between SRPK1 and oncogenic signaling circuits together with the possibility of aiming SRPK1 in the treatment of cancer.
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Affiliation(s)
- Mitesh Patel
- Department of Biosciences, Bapalal Vaidya Botanical Research Centre, Veer Narmad South Gujarat University, Surat, Gujarat, India
| | - Manojkumar Sachidanandan
- Department of Oral Radiology, College of Dentistry, University of Hail, P O Box 2440, Hail, Saudi Arabia
| | - Mohd Adnan
- Department of Biology, Faculty of Science, University of Hail, P O Box 2440, Hail, Saudi Arabia.
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12
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Altered conformational landscape and dimerization dependency underpins the activation of EGFR by αC- β4 loop insertion mutations. Proc Natl Acad Sci U S A 2018; 115:E8162-E8171. [PMID: 30104348 DOI: 10.1073/pnas.1803152115] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Mutational activation of epidermal growth factor receptor (EGFR) in human cancers involves both point mutations and complex mutations (insertions and deletions). In particular, short in-frame insertion mutations within a conserved αC-β4 loop in the EGFR kinase domain are frequently observed in tumor samples and patients harboring these mutations are insensitive to first-generation EGFR inhibitors. Despite the prevalence and clinical relevance of insertion mutations, the mechanisms by which these mutations regulate EGFR activity and contribute to drug sensitivity are poorly understood. Using cell-based mutation screening, we find that the precise location, length, and sequence of the inserted segment are critical for ligand-independent EGFR activation and downstream signaling. We identify three insertion mutations (N771_P772insN, D770_N771insG, and D770>GY) that activate EGFR in a unique way by relying more on the "acceptor" interface for kinase activation. Our drug inhibition studies indicate that these activating insertion mutations respond more favorably to osimertinib, a recently Food and Drug Administration-approved EGFR inhibitor for T790M-positive patients with lung cancer. Molecular dynamics simulations and umbrella sampling of WT and mutant EGFR suggest a model in which activating insertion mutations increase catalytic activity by relieving key autoinhibitory interactions associated with αC-helix movement and by lowering the transition free energy ([Formula: see text]) between active and inactive states. Our studies also identify a transition state sampled by activating insertion mutations that can be exploited in the design of mutant-selective EGFR inhibitors.
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13
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Chen Y, Huang Q, Liu W, Zhu Q, Cui CP, Xu L, Guo X, Wang P, Liu J, Dong G, Wei W, Liu CH, Feng Z, He F, Zhang L. Mutually exclusive acetylation and ubiquitylation of the splicing factor SRSF5 control tumor growth. Nat Commun 2018; 9:2464. [PMID: 29942010 PMCID: PMC6018636 DOI: 10.1038/s41467-018-04815-3] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 05/18/2018] [Indexed: 12/30/2022] Open
Abstract
Most tumor cells take up more glucose than normal cells. Splicing dysregulation is one of the molecular hallmarks of cancer. However, the role of splicing factor in glucose metabolism and tumor development remains poorly defined. Here, we show that upon glucose intake, the splicing factor SRSF5 is specifically induced through Tip60-mediated acetylation on K125, which antagonizes Smurf1-mediated ubiquitylation. SRSF5 promotes the alternative splicing of CCAR1 to produce CCAR1S proteins, which promote tumor growth by enhancing glucose consumption and acetyl-CoA production. Conversely, upon glucose starvation, SRSF5 is deacetylated by HDAC1, and ubiquitylated by Smurf1 on the same lysine, resulting in proteasomal degradation of SRSF5. The CCAR1L proteins accumulate to promote apoptosis. Importantly, SRSF5 is hyperacetylated and upregulated in human lung cancers, which correlates with increased CCAR1S expression and tumor progression. Thus, SRSF5 responds to high glucose to promote cancer development, and SRSF5-CCAR1 axis may be valuable targets for cancer therapeutics.
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Affiliation(s)
- Yuhan Chen
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center of Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, 100850, China.,Department of Genomics and Proteomics, Beijing Institute of Radiation Medicine, Beijing, 100850, China.,Affiliated BaYi Children's Hospital, PLA Army General Hospital, National Engineering Laboratory for Birth Defects Prevention and Control of Key Technology, Beijing Key Laboratory of Pediatric Organ Failure, Beijing, 100700, China
| | - Qingyang Huang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center of Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, 100850, China.,Department of Genomics and Proteomics, Beijing Institute of Radiation Medicine, Beijing, 100850, China
| | - Wen Liu
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center of Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, 100850, China.,Department of Genomics and Proteomics, Beijing Institute of Radiation Medicine, Beijing, 100850, China
| | - Qiong Zhu
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center of Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, 100850, China.,Department of Genomics and Proteomics, Beijing Institute of Radiation Medicine, Beijing, 100850, China
| | - Chun-Ping Cui
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center of Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, 100850, China.,Department of Genomics and Proteomics, Beijing Institute of Radiation Medicine, Beijing, 100850, China
| | - Liang Xu
- Department of Genomics and Proteomics, Beijing Institute of Radiation Medicine, Beijing, 100850, China.,Department of Biochemistry and Molecular Biology, Anhui Medical University, Hefei, 230032, Anhui, China
| | - Xing Guo
- Department of Genomics and Proteomics, Beijing Institute of Radiation Medicine, Beijing, 100850, China.,Department of Neurobiology, Key Laboratory of Human Functional Genomics of Jiangsu Province, Nanjing Medical University, Nanjing, 211166, Jiangsu, China
| | - Ping Wang
- Department of Central Laboratory, Shanghai Tenth People's Hospital, School of Life Science and Technology, Tongji University, Shanghai, 200072, China
| | - Jingwen Liu
- Department of General Surgery, Chinese People's Liberation Army General Hospital, Beijing, 100853, China
| | - Guanglong Dong
- Department of General Surgery, Chinese People's Liberation Army General Hospital, Beijing, 100853, China
| | - Wenyi Wei
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, 02115, USA
| | - Cui Hua Liu
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Zhichun Feng
- Affiliated BaYi Children's Hospital, PLA Army General Hospital, National Engineering Laboratory for Birth Defects Prevention and Control of Key Technology, Beijing Key Laboratory of Pediatric Organ Failure, Beijing, 100700, China
| | - Fuchu He
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center of Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, 100850, China. .,Department of Genomics and Proteomics, Beijing Institute of Radiation Medicine, Beijing, 100850, China.
| | - Lingqiang Zhang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center of Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, 100850, China. .,Department of Genomics and Proteomics, Beijing Institute of Radiation Medicine, Beijing, 100850, China. .,School of Life Science, Jiangsu Normal University, Xuzhou, 221116, Jiangsu, China.
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14
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Hatcher JM, Wu G, Zeng C, Zhu J, Meng F, Patel S, Wang W, Ficarro SB, Leggett AL, Powell CE, Marto JA, Zhang K, Ngo JCK, Fu XD, Zhang T, Gray NS. SRPKIN-1: A Covalent SRPK1/2 Inhibitor that Potently Converts VEGF from Pro-angiogenic to Anti-angiogenic Isoform. Cell Chem Biol 2018; 25:460-470.e6. [PMID: 29478907 PMCID: PMC5973797 DOI: 10.1016/j.chembiol.2018.01.013] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 11/03/2017] [Accepted: 01/26/2018] [Indexed: 01/07/2023]
Abstract
The SRPK family of kinases regulates pre-mRNA splicing by phosphorylating serine/arginine (SR)-rich splicing factors, signals splicing control in response to extracellular stimuli, and contributes to tumorigenesis, suggesting that these splicing kinases are potential therapeutic targets. Here, we report the development of the first irreversible SRPK inhibitor, SRPKIN-1, which is also the first kinase inhibitor that forms a covalent bond with a tyrosine phenol group in the ATP-binding pocket. Kinome-wide profiling demonstrates its selectivity for SRPK1/2, and SRPKIN-1 attenuates SR protein phosphorylation at submicromolar concentrations. Vascular endothelial growth factor (VEGF) is a known target for SRPK-regulated splicing and, relative to the first-generation SRPK inhibitor SRPIN340 or small interfering RNA-mediated SRPK knockdown, SRPKIN-1 is more potent in converting the pro-angiogenic VEGF-A165a to the anti-angiogenic VEGF-A165b isoform and in blocking laser-induced neovascularization in a murine retinal model. These findings encourage further development of SRPK inhibitors for treatment of age-related macular degeneration.
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Affiliation(s)
- John M. Hatcher
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Guowei Wu
- Department of Cellular and Molecular Medicine, Institute of Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Chuyue Zeng
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong Special Administrative Region NA, China
| | - Jie Zhu
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA,Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou 510623, China
| | - Fan Meng
- Department of Cellular and Molecular Medicine, Institute of Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Sherrina Patel
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Wenqiu Wang
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Scott B. Ficarro
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA,Department of Oncologic Pathology and Blais Proteomics Center, Dana-Farber Cancer Institute, Boston, MA 02115, USA,Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Alan L. Leggett
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Chelsea E. Powell
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Jarrod A. Marto
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA,Department of Oncologic Pathology and Blais Proteomics Center, Dana-Farber Cancer Institute, Boston, MA 02115, USA,Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Kang Zhang
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jacky Chi Ki Ngo
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong Special Administrative Region NA, China
| | - Xiang-Dong Fu
- Department of Cellular and Molecular Medicine, Institute of Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA,Correspondence: (X.-D.F.), (T.Z.), (N.S.G.)
| | - Tinghu Zhang
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA,Correspondence: (X.-D.F.), (T.Z.), (N.S.G.)
| | - Nathanael S. Gray
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA,Correspondence: (X.-D.F.), (T.Z.), (N.S.G.)
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15
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Koutroumani M, Papadopoulos GE, Vlassi M, Nikolakaki E, Giannakouros T. Evidence for disulfide bonds in SR Protein Kinase 1 (SRPK1) that are required for activity and nuclear localization. PLoS One 2017; 12:e0171328. [PMID: 28166275 PMCID: PMC5293202 DOI: 10.1371/journal.pone.0171328] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 01/18/2017] [Indexed: 11/18/2022] Open
Abstract
Serine/arginine protein kinases (SRPKs) phosphorylate Arg/Ser dipeptide-containing proteins that play crucial roles in a broad spectrum of basic cellular processes. The existence of a large internal spacer sequence that separates the bipartite kinase catalytic core is a unique structural feature of SRPKs. Previous structural studies on a catalytically active fragment of SRPK1, which lacks the main part of the spacer domain, revealed that SRPK1 remains in an active state without any post-translational modifications or specific intra-protein interactions, while the spacer domain is depicted as a loop structure, outside the kinase core. Using systematic mutagenesis we now provide evidence that replacement of any individual cysteine residue in the spacer, apart from Cys414, or in its proximal flaking ends of the two kinase catalytic domains has an impact on kinase activity. Furthermore, the cysteine residues are critical for nuclear translocation of SRPK1 in response to genotoxic stress and SRPK1-dependent splicing of a reporter gene. While replacement of Cys207, Cys502 and Cys539 of the catalytic domains is predicted to distort the kinase active structure, our findings suggest that Cys356, Cys386, Cys427 and Cys455 of the spacer domain and Cys188 of the first catalytic domain are engaged in disulfide bridging. We propose that such a network of intramolecular disulfide bonds mediates the bending of the spacer region thus allowing the proximal positioning of the two catalytic subunits which is a prerequisite for SRPK1 activity.
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Affiliation(s)
- Maria Koutroumani
- Laboratory of Biochemistry, Department of Chemistry, Aristotle University, Thessaloniki, Greece
| | | | - Metaxia Vlassi
- Institute of Biosciences & Applications, National Centre for Scientific Research "Demokritos", Athens, Greece
| | - Eleni Nikolakaki
- Laboratory of Biochemistry, Department of Chemistry, Aristotle University, Thessaloniki, Greece
- * E-mail: (TG); (EN)
| | - Thomas Giannakouros
- Laboratory of Biochemistry, Department of Chemistry, Aristotle University, Thessaloniki, Greece
- * E-mail: (TG); (EN)
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16
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Sigala I, Ganidis G, Thysiadis S, Zografos AL, Giannakouros T, Sarli V, Nikolakaki E. Lynamicin D an antimicrobial natural product affects splicing by inducing the expression of SR protein kinase 1. Bioorg Med Chem 2017; 25:1622-1629. [PMID: 28139279 DOI: 10.1016/j.bmc.2017.01.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 12/15/2016] [Accepted: 01/16/2017] [Indexed: 10/20/2022]
Abstract
The first total synthesis of the antimicrobial natural product lynamicin D has been developed using a Suzuki coupling to construct the bisindole pyrrole skeleton. An evaluation of the biological activity of lynamicin D reveals that it has a minor effect on cell viability but it can modulate splicing of pre-mRNAs. We provide evidence that this effect is mainly due to the ability of lynamicin D to alter the levels of SRPK1, the key kinase involved in both constitutive and alternative splicing.
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Affiliation(s)
- Ioanna Sigala
- Department of Chemistry, Aristotle University of Thessaloniki, University Campus, 54124 Thessaloniki, Greece
| | - George Ganidis
- Department of Chemistry, Aristotle University of Thessaloniki, University Campus, 54124 Thessaloniki, Greece
| | - Savvas Thysiadis
- Department of Chemistry, Aristotle University of Thessaloniki, University Campus, 54124 Thessaloniki, Greece
| | - Alexandros L Zografos
- Department of Chemistry, Aristotle University of Thessaloniki, University Campus, 54124 Thessaloniki, Greece
| | - Thomas Giannakouros
- Department of Chemistry, Aristotle University of Thessaloniki, University Campus, 54124 Thessaloniki, Greece
| | - Vasiliki Sarli
- Department of Chemistry, Aristotle University of Thessaloniki, University Campus, 54124 Thessaloniki, Greece.
| | - Eleni Nikolakaki
- Department of Chemistry, Aristotle University of Thessaloniki, University Campus, 54124 Thessaloniki, Greece
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17
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Blue GM, Humphreys D, Szot J, Major J, Chapman G, Bosman A, Kirk EP, Sholler GF, Harvey RP, Dunwoodie SL, Winlaw DS. The promises and challenges of exome sequencing in familial, non-syndromic congenital heart disease. Int J Cardiol 2016; 230:155-163. [PMID: 27989580 DOI: 10.1016/j.ijcard.2016.12.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 11/30/2016] [Accepted: 12/11/2016] [Indexed: 12/27/2022]
Abstract
BACKGROUND Exome sequencing is an established strategy to identify causal variants in families with two or more members affected by congenital heart disease (CHD). This unbiased approach, in which both rare and common variants are identified, makes it suitable to research complex, heterogeneous diseases such as CHD. METHODS AND RESULTS Exome sequencing was performed on two affected members of a three generation family with atrial septal defects (ASD), suggesting a dominant inheritance pattern. Variants were filtered using two bioinformatics pipelines and prioritised according to in silico prediction programs. Segregation studies and functional analyses were used to assess co-segregation with disease and effects on protein function, respectively. Following the data and in silico analyses, ten candidate variants were prioritised. Of these, SRPK2 (c.2044C>T[p.Arg682Trp]) and NOTCH1 (c.3835C>T[p.Arg1279Cys]), co-segregated with disease in the family; however, previous functional analyses on SRPK2 make this an unlikely candidate. Functional analyses in the variant (c.3835C>T[p.Arg1279Cys]) of the known CHD gene NOTCH1 demonstrated a non-significant decrease in signalling activity. CONCLUSION This study demonstrates both the potential, as well as the challenges, of applying exome sequencing to complex diseases such as CHD. While in silico evidence and segregation analyses in the NOTCH1 p.Arg1279Cys variant are highly suggestive of pathogenicity, the minimal change in signalling capacity suggests that other variants may be required for CHD development. This study highlights the difficulties of applying exome sequencing in familial, non-syndromic CHD in the clinical environment and a cautionary note in the interpretation of apparently causal abnormalities in silico without supportive functional data.
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Affiliation(s)
- Gillian M Blue
- Kids Heart Research, The Children's Hospital at Westmead, Sydney, Australia; The Heart Centre for Children, The Children's Hospital at Westmead, Sydney, Australia; Sydney Medical School, University of Sydney, Australia
| | - David Humphreys
- Victor Chang Cardiac Research Institute, Darlinghurst, Sydney, Australia; St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, Australia
| | - Justin Szot
- Victor Chang Cardiac Research Institute, Darlinghurst, Sydney, Australia; School of Biotechnology and Biomolecular Sciences, Faculty of Science, University of New South Wales, Sydney, Australia
| | - Joelene Major
- Victor Chang Cardiac Research Institute, Darlinghurst, Sydney, Australia
| | - Gavin Chapman
- Victor Chang Cardiac Research Institute, Darlinghurst, Sydney, Australia; St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, Australia
| | - Alexis Bosman
- Victor Chang Cardiac Research Institute, Darlinghurst, Sydney, Australia
| | - Edwin P Kirk
- Department of Medical Genetics, Sydney Children's Hospital, Sydney, Australia; School of Women's and Children's Health, Faculty of Medicine, University of New South Wales, Sydney, Australia
| | - Gary F Sholler
- The Heart Centre for Children, The Children's Hospital at Westmead, Sydney, Australia; Sydney Medical School, University of Sydney, Australia
| | - Richard P Harvey
- Victor Chang Cardiac Research Institute, Darlinghurst, Sydney, Australia; St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, Australia; School of Biotechnology and Biomolecular Sciences, Faculty of Science, University of New South Wales, Sydney, Australia
| | - Sally L Dunwoodie
- Victor Chang Cardiac Research Institute, Darlinghurst, Sydney, Australia; St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, Australia; School of Biotechnology and Biomolecular Sciences, Faculty of Science, University of New South Wales, Sydney, Australia
| | - David S Winlaw
- Kids Heart Research, The Children's Hospital at Westmead, Sydney, Australia; The Heart Centre for Children, The Children's Hospital at Westmead, Sydney, Australia; Sydney Medical School, University of Sydney, Australia.
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18
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Morooka S, Hoshina M, Kii I, Okabe T, Kojima H, Inoue N, Okuno Y, Denawa M, Yoshida S, Fukuhara J, Ninomiya K, Ikura T, Furuya T, Nagano T, Noda K, Ishida S, Hosoya T, Ito N, Yoshimura N, Hagiwara M. Identification of a Dual Inhibitor of SRPK1 and CK2 That Attenuates Pathological Angiogenesis of Macular Degeneration in Mice. Mol Pharmacol 2015; 88:316-25. [PMID: 25993998 DOI: 10.1124/mol.114.097345] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 05/20/2015] [Indexed: 12/28/2022] Open
Abstract
Excessive angiogenesis contributes to numerous diseases, including cancer and blinding retinopathy. Antibodies against vascular endothelial growth factor (VEGF) have been approved and are widely used in clinical treatment. Our previous studies using SRPIN340, a small molecule inhibitor of SRPK1 (serine-arginine protein kinase 1), demonstrated that SRPK1 is a potential target for the development of antiangiogenic drugs. In this study, we solved the structure of SRPK1 bound to SRPIN340 by X-ray crystallography. Using pharmacophore docking models followed by in vitro kinase assays, we screened a large-scale chemical library, and thus identified a new inhibitor of SRPK1. This inhibitor, SRPIN803, prevented VEGF production more effectively than SRPIN340 owing to the dual inhibition of SRPK1 and CK2 (casein kinase 2). In a mouse model of age-related macular degeneration, topical administration of eye ointment containing SRPIN803 significantly inhibited choroidal neovascularization, suggesting a clinical potential of SRPIN803 as a topical ointment for ocular neovascularization. Thus SRPIN803 merits further investigation as a novel inhibitor of VEGF.
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Affiliation(s)
- Satoshi Morooka
- Department of Ophthalmology and Visual Sciences (S.M., N.Y.), Department of Anatomy and Developmental Biology (S.M., I.K., Ke.N., Ma.H.), and Medical Research Support Center (Y.O., M.D.), Graduate School of Medicine, Kyoto University, Kyoto, Japan; Laboratory of Structural Biology, Medical Research Institute (Mi.H., No.I., T.I.), and Laboratory of Chemical Bioscience, Institute of Biomaterials and Bioengineering (S.Y., T.H.), Tokyo Medical and Dental University, Tokyo, Japan; Open Innovation Center for Drug Discovery, The University of Tokyo, Tokyo, Japan (T.O., H.K., T.N.); PharmaDesign, Inc., Tokyo, Japan (Na.I., T.F.); and Department of Ophthalmology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan (J.F., Ko.N., S.I.)
| | - Mitsuteru Hoshina
- Department of Ophthalmology and Visual Sciences (S.M., N.Y.), Department of Anatomy and Developmental Biology (S.M., I.K., Ke.N., Ma.H.), and Medical Research Support Center (Y.O., M.D.), Graduate School of Medicine, Kyoto University, Kyoto, Japan; Laboratory of Structural Biology, Medical Research Institute (Mi.H., No.I., T.I.), and Laboratory of Chemical Bioscience, Institute of Biomaterials and Bioengineering (S.Y., T.H.), Tokyo Medical and Dental University, Tokyo, Japan; Open Innovation Center for Drug Discovery, The University of Tokyo, Tokyo, Japan (T.O., H.K., T.N.); PharmaDesign, Inc., Tokyo, Japan (Na.I., T.F.); and Department of Ophthalmology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan (J.F., Ko.N., S.I.)
| | - Isao Kii
- Department of Ophthalmology and Visual Sciences (S.M., N.Y.), Department of Anatomy and Developmental Biology (S.M., I.K., Ke.N., Ma.H.), and Medical Research Support Center (Y.O., M.D.), Graduate School of Medicine, Kyoto University, Kyoto, Japan; Laboratory of Structural Biology, Medical Research Institute (Mi.H., No.I., T.I.), and Laboratory of Chemical Bioscience, Institute of Biomaterials and Bioengineering (S.Y., T.H.), Tokyo Medical and Dental University, Tokyo, Japan; Open Innovation Center for Drug Discovery, The University of Tokyo, Tokyo, Japan (T.O., H.K., T.N.); PharmaDesign, Inc., Tokyo, Japan (Na.I., T.F.); and Department of Ophthalmology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan (J.F., Ko.N., S.I.)
| | - Takayoshi Okabe
- Department of Ophthalmology and Visual Sciences (S.M., N.Y.), Department of Anatomy and Developmental Biology (S.M., I.K., Ke.N., Ma.H.), and Medical Research Support Center (Y.O., M.D.), Graduate School of Medicine, Kyoto University, Kyoto, Japan; Laboratory of Structural Biology, Medical Research Institute (Mi.H., No.I., T.I.), and Laboratory of Chemical Bioscience, Institute of Biomaterials and Bioengineering (S.Y., T.H.), Tokyo Medical and Dental University, Tokyo, Japan; Open Innovation Center for Drug Discovery, The University of Tokyo, Tokyo, Japan (T.O., H.K., T.N.); PharmaDesign, Inc., Tokyo, Japan (Na.I., T.F.); and Department of Ophthalmology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan (J.F., Ko.N., S.I.)
| | - Hirotatsu Kojima
- Department of Ophthalmology and Visual Sciences (S.M., N.Y.), Department of Anatomy and Developmental Biology (S.M., I.K., Ke.N., Ma.H.), and Medical Research Support Center (Y.O., M.D.), Graduate School of Medicine, Kyoto University, Kyoto, Japan; Laboratory of Structural Biology, Medical Research Institute (Mi.H., No.I., T.I.), and Laboratory of Chemical Bioscience, Institute of Biomaterials and Bioengineering (S.Y., T.H.), Tokyo Medical and Dental University, Tokyo, Japan; Open Innovation Center for Drug Discovery, The University of Tokyo, Tokyo, Japan (T.O., H.K., T.N.); PharmaDesign, Inc., Tokyo, Japan (Na.I., T.F.); and Department of Ophthalmology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan (J.F., Ko.N., S.I.)
| | - Naoko Inoue
- Department of Ophthalmology and Visual Sciences (S.M., N.Y.), Department of Anatomy and Developmental Biology (S.M., I.K., Ke.N., Ma.H.), and Medical Research Support Center (Y.O., M.D.), Graduate School of Medicine, Kyoto University, Kyoto, Japan; Laboratory of Structural Biology, Medical Research Institute (Mi.H., No.I., T.I.), and Laboratory of Chemical Bioscience, Institute of Biomaterials and Bioengineering (S.Y., T.H.), Tokyo Medical and Dental University, Tokyo, Japan; Open Innovation Center for Drug Discovery, The University of Tokyo, Tokyo, Japan (T.O., H.K., T.N.); PharmaDesign, Inc., Tokyo, Japan (Na.I., T.F.); and Department of Ophthalmology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan (J.F., Ko.N., S.I.)
| | - Yukiko Okuno
- Department of Ophthalmology and Visual Sciences (S.M., N.Y.), Department of Anatomy and Developmental Biology (S.M., I.K., Ke.N., Ma.H.), and Medical Research Support Center (Y.O., M.D.), Graduate School of Medicine, Kyoto University, Kyoto, Japan; Laboratory of Structural Biology, Medical Research Institute (Mi.H., No.I., T.I.), and Laboratory of Chemical Bioscience, Institute of Biomaterials and Bioengineering (S.Y., T.H.), Tokyo Medical and Dental University, Tokyo, Japan; Open Innovation Center for Drug Discovery, The University of Tokyo, Tokyo, Japan (T.O., H.K., T.N.); PharmaDesign, Inc., Tokyo, Japan (Na.I., T.F.); and Department of Ophthalmology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan (J.F., Ko.N., S.I.)
| | - Masatsugu Denawa
- Department of Ophthalmology and Visual Sciences (S.M., N.Y.), Department of Anatomy and Developmental Biology (S.M., I.K., Ke.N., Ma.H.), and Medical Research Support Center (Y.O., M.D.), Graduate School of Medicine, Kyoto University, Kyoto, Japan; Laboratory of Structural Biology, Medical Research Institute (Mi.H., No.I., T.I.), and Laboratory of Chemical Bioscience, Institute of Biomaterials and Bioengineering (S.Y., T.H.), Tokyo Medical and Dental University, Tokyo, Japan; Open Innovation Center for Drug Discovery, The University of Tokyo, Tokyo, Japan (T.O., H.K., T.N.); PharmaDesign, Inc., Tokyo, Japan (Na.I., T.F.); and Department of Ophthalmology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan (J.F., Ko.N., S.I.)
| | - Suguru Yoshida
- Department of Ophthalmology and Visual Sciences (S.M., N.Y.), Department of Anatomy and Developmental Biology (S.M., I.K., Ke.N., Ma.H.), and Medical Research Support Center (Y.O., M.D.), Graduate School of Medicine, Kyoto University, Kyoto, Japan; Laboratory of Structural Biology, Medical Research Institute (Mi.H., No.I., T.I.), and Laboratory of Chemical Bioscience, Institute of Biomaterials and Bioengineering (S.Y., T.H.), Tokyo Medical and Dental University, Tokyo, Japan; Open Innovation Center for Drug Discovery, The University of Tokyo, Tokyo, Japan (T.O., H.K., T.N.); PharmaDesign, Inc., Tokyo, Japan (Na.I., T.F.); and Department of Ophthalmology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan (J.F., Ko.N., S.I.)
| | - Junichi Fukuhara
- Department of Ophthalmology and Visual Sciences (S.M., N.Y.), Department of Anatomy and Developmental Biology (S.M., I.K., Ke.N., Ma.H.), and Medical Research Support Center (Y.O., M.D.), Graduate School of Medicine, Kyoto University, Kyoto, Japan; Laboratory of Structural Biology, Medical Research Institute (Mi.H., No.I., T.I.), and Laboratory of Chemical Bioscience, Institute of Biomaterials and Bioengineering (S.Y., T.H.), Tokyo Medical and Dental University, Tokyo, Japan; Open Innovation Center for Drug Discovery, The University of Tokyo, Tokyo, Japan (T.O., H.K., T.N.); PharmaDesign, Inc., Tokyo, Japan (Na.I., T.F.); and Department of Ophthalmology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan (J.F., Ko.N., S.I.)
| | - Kensuke Ninomiya
- Department of Ophthalmology and Visual Sciences (S.M., N.Y.), Department of Anatomy and Developmental Biology (S.M., I.K., Ke.N., Ma.H.), and Medical Research Support Center (Y.O., M.D.), Graduate School of Medicine, Kyoto University, Kyoto, Japan; Laboratory of Structural Biology, Medical Research Institute (Mi.H., No.I., T.I.), and Laboratory of Chemical Bioscience, Institute of Biomaterials and Bioengineering (S.Y., T.H.), Tokyo Medical and Dental University, Tokyo, Japan; Open Innovation Center for Drug Discovery, The University of Tokyo, Tokyo, Japan (T.O., H.K., T.N.); PharmaDesign, Inc., Tokyo, Japan (Na.I., T.F.); and Department of Ophthalmology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan (J.F., Ko.N., S.I.)
| | - Teikichi Ikura
- Department of Ophthalmology and Visual Sciences (S.M., N.Y.), Department of Anatomy and Developmental Biology (S.M., I.K., Ke.N., Ma.H.), and Medical Research Support Center (Y.O., M.D.), Graduate School of Medicine, Kyoto University, Kyoto, Japan; Laboratory of Structural Biology, Medical Research Institute (Mi.H., No.I., T.I.), and Laboratory of Chemical Bioscience, Institute of Biomaterials and Bioengineering (S.Y., T.H.), Tokyo Medical and Dental University, Tokyo, Japan; Open Innovation Center for Drug Discovery, The University of Tokyo, Tokyo, Japan (T.O., H.K., T.N.); PharmaDesign, Inc., Tokyo, Japan (Na.I., T.F.); and Department of Ophthalmology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan (J.F., Ko.N., S.I.)
| | - Toshio Furuya
- Department of Ophthalmology and Visual Sciences (S.M., N.Y.), Department of Anatomy and Developmental Biology (S.M., I.K., Ke.N., Ma.H.), and Medical Research Support Center (Y.O., M.D.), Graduate School of Medicine, Kyoto University, Kyoto, Japan; Laboratory of Structural Biology, Medical Research Institute (Mi.H., No.I., T.I.), and Laboratory of Chemical Bioscience, Institute of Biomaterials and Bioengineering (S.Y., T.H.), Tokyo Medical and Dental University, Tokyo, Japan; Open Innovation Center for Drug Discovery, The University of Tokyo, Tokyo, Japan (T.O., H.K., T.N.); PharmaDesign, Inc., Tokyo, Japan (Na.I., T.F.); and Department of Ophthalmology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan (J.F., Ko.N., S.I.)
| | - Tetsuo Nagano
- Department of Ophthalmology and Visual Sciences (S.M., N.Y.), Department of Anatomy and Developmental Biology (S.M., I.K., Ke.N., Ma.H.), and Medical Research Support Center (Y.O., M.D.), Graduate School of Medicine, Kyoto University, Kyoto, Japan; Laboratory of Structural Biology, Medical Research Institute (Mi.H., No.I., T.I.), and Laboratory of Chemical Bioscience, Institute of Biomaterials and Bioengineering (S.Y., T.H.), Tokyo Medical and Dental University, Tokyo, Japan; Open Innovation Center for Drug Discovery, The University of Tokyo, Tokyo, Japan (T.O., H.K., T.N.); PharmaDesign, Inc., Tokyo, Japan (Na.I., T.F.); and Department of Ophthalmology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan (J.F., Ko.N., S.I.)
| | - Kousuke Noda
- Department of Ophthalmology and Visual Sciences (S.M., N.Y.), Department of Anatomy and Developmental Biology (S.M., I.K., Ke.N., Ma.H.), and Medical Research Support Center (Y.O., M.D.), Graduate School of Medicine, Kyoto University, Kyoto, Japan; Laboratory of Structural Biology, Medical Research Institute (Mi.H., No.I., T.I.), and Laboratory of Chemical Bioscience, Institute of Biomaterials and Bioengineering (S.Y., T.H.), Tokyo Medical and Dental University, Tokyo, Japan; Open Innovation Center for Drug Discovery, The University of Tokyo, Tokyo, Japan (T.O., H.K., T.N.); PharmaDesign, Inc., Tokyo, Japan (Na.I., T.F.); and Department of Ophthalmology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan (J.F., Ko.N., S.I.)
| | - Susumu Ishida
- Department of Ophthalmology and Visual Sciences (S.M., N.Y.), Department of Anatomy and Developmental Biology (S.M., I.K., Ke.N., Ma.H.), and Medical Research Support Center (Y.O., M.D.), Graduate School of Medicine, Kyoto University, Kyoto, Japan; Laboratory of Structural Biology, Medical Research Institute (Mi.H., No.I., T.I.), and Laboratory of Chemical Bioscience, Institute of Biomaterials and Bioengineering (S.Y., T.H.), Tokyo Medical and Dental University, Tokyo, Japan; Open Innovation Center for Drug Discovery, The University of Tokyo, Tokyo, Japan (T.O., H.K., T.N.); PharmaDesign, Inc., Tokyo, Japan (Na.I., T.F.); and Department of Ophthalmology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan (J.F., Ko.N., S.I.)
| | - Takamitsu Hosoya
- Department of Ophthalmology and Visual Sciences (S.M., N.Y.), Department of Anatomy and Developmental Biology (S.M., I.K., Ke.N., Ma.H.), and Medical Research Support Center (Y.O., M.D.), Graduate School of Medicine, Kyoto University, Kyoto, Japan; Laboratory of Structural Biology, Medical Research Institute (Mi.H., No.I., T.I.), and Laboratory of Chemical Bioscience, Institute of Biomaterials and Bioengineering (S.Y., T.H.), Tokyo Medical and Dental University, Tokyo, Japan; Open Innovation Center for Drug Discovery, The University of Tokyo, Tokyo, Japan (T.O., H.K., T.N.); PharmaDesign, Inc., Tokyo, Japan (Na.I., T.F.); and Department of Ophthalmology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan (J.F., Ko.N., S.I.)
| | - Nobutoshi Ito
- Department of Ophthalmology and Visual Sciences (S.M., N.Y.), Department of Anatomy and Developmental Biology (S.M., I.K., Ke.N., Ma.H.), and Medical Research Support Center (Y.O., M.D.), Graduate School of Medicine, Kyoto University, Kyoto, Japan; Laboratory of Structural Biology, Medical Research Institute (Mi.H., No.I., T.I.), and Laboratory of Chemical Bioscience, Institute of Biomaterials and Bioengineering (S.Y., T.H.), Tokyo Medical and Dental University, Tokyo, Japan; Open Innovation Center for Drug Discovery, The University of Tokyo, Tokyo, Japan (T.O., H.K., T.N.); PharmaDesign, Inc., Tokyo, Japan (Na.I., T.F.); and Department of Ophthalmology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan (J.F., Ko.N., S.I.)
| | - Nagahisa Yoshimura
- Department of Ophthalmology and Visual Sciences (S.M., N.Y.), Department of Anatomy and Developmental Biology (S.M., I.K., Ke.N., Ma.H.), and Medical Research Support Center (Y.O., M.D.), Graduate School of Medicine, Kyoto University, Kyoto, Japan; Laboratory of Structural Biology, Medical Research Institute (Mi.H., No.I., T.I.), and Laboratory of Chemical Bioscience, Institute of Biomaterials and Bioengineering (S.Y., T.H.), Tokyo Medical and Dental University, Tokyo, Japan; Open Innovation Center for Drug Discovery, The University of Tokyo, Tokyo, Japan (T.O., H.K., T.N.); PharmaDesign, Inc., Tokyo, Japan (Na.I., T.F.); and Department of Ophthalmology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan (J.F., Ko.N., S.I.)
| | - Masatoshi Hagiwara
- Department of Ophthalmology and Visual Sciences (S.M., N.Y.), Department of Anatomy and Developmental Biology (S.M., I.K., Ke.N., Ma.H.), and Medical Research Support Center (Y.O., M.D.), Graduate School of Medicine, Kyoto University, Kyoto, Japan; Laboratory of Structural Biology, Medical Research Institute (Mi.H., No.I., T.I.), and Laboratory of Chemical Bioscience, Institute of Biomaterials and Bioengineering (S.Y., T.H.), Tokyo Medical and Dental University, Tokyo, Japan; Open Innovation Center for Drug Discovery, The University of Tokyo, Tokyo, Japan (T.O., H.K., T.N.); PharmaDesign, Inc., Tokyo, Japan (Na.I., T.F.); and Department of Ophthalmology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan (J.F., Ko.N., S.I.)
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Primary structural features of SR-like protein acinusS govern the phosphorylation mechanism by SRPK2. Biochem J 2014; 459:181-91. [PMID: 24444330 DOI: 10.1042/bj20131091] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
SRPKs (serine/arginine protein kinases) are highly specific kinases that recognize and phosphorylate RS (Arg-Ser) dipeptide repeats. It has been shown previously that SRPK1 phosphorylates the RS domain of SRSF1 (serine/arginine splicing factor 1) at multiple sites using a directional and processive mechanism. Such ability to processively phosphorylate substrates is proposed to be an inherent characteristic of SRPKs. SRPK2 is highly related to SRPK1 in sequence and in vitro properties, yet it has been shown to have distinct substrate specificity and physiological function in vivo. To study the molecular basis for substrate specificity of SRPK2, we investigated the roles of the non-kinase regions and a conserved docking groove of SRPK2 in the recognition and phosphorylation of different substrates: SRSF1 and acinusS. Our results reveal that a conserved electronegative docking groove in SRPK2, but not its non-kinase regions, is responsible for substrate binding regardless of their identities. Although SRPK2 phosphorylates SRSF1 in a processive manner as predicted, an electronegative region on acinusS restricts SRPK2 phosphorylation to a single specific site despite the presence of multiple RS dipeptides. These results suggest that primary structural elements on the substrates serve as key regulatory roles in determining the phosphorylation mechanism of SRPK2.
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Abstract
The splicing of mRNA requires a group of essential factors known as SR proteins, which participate in the maturation of the spliceosome. These proteins contain one or two RNA recognition motifs and a C-terminal domain rich in Arg-Ser repeats (RS domain). SR proteins are phosphorylated at numerous serines in the RS domain by the SR-specific protein kinase (SRPK) family of protein kinases. RS domain phosphorylation is necessary for entry of SR proteins into the nucleus, and may also play important roles in alternative splicing, mRNA export, and other processing events. Although SR proteins are polyphosphorylated in vivo, the mechanism underlying this complex reaction has only been recently elucidated. Human alternative splicing factor [serine/arginine-rich splicing factor 1 (SRSF1)], a prototype for the SR protein family, is regiospecifically phosphorylated by SRPK1, a post-translational modification that controls cytoplasmic-nuclear localization. SRPK1 binds SRSF1 with unusually high affinity, and rapidly modifies about 10-12 serines in the N-terminal region of the RS domain (RS1), using a mechanism that incorporates sequential, C-terminal to N-terminal phosphorylation and several processive steps. SRPK1 employs a highly dynamic feeding mechanism for RS domain phosphorylation in which the N-terminal portion of RS1 is initially bound to a docking groove in the large lobe of the kinase domain. Upon subsequent rounds of phosphorylation, this N-terminal segment translocates into the active site, and a β-strand in RNA recognition motif 2 unfolds and occupies the docking groove. These studies indicate that efficient regiospecific phosphorylation of SRSF1 is the result of a contoured binding cavity in SRPK1, a lengthy Arg-Ser repetitive segment in the RS domain, and a highly directional processing mechanism.
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Affiliation(s)
- Gourisankar Ghosh
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
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Giannakouros T, Nikolakaki E, Mylonis I, Georgatsou E. Serine-arginine protein kinases: a small protein kinase family with a large cellular presence. FEBS J 2011; 278:570-86. [DOI: 10.1111/j.1742-4658.2010.07987.x] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Liu S, Zhou Z, Lin Z, Ouyang Q, Zhang J, Tian S, Xing M. Identification of a nuclear localization motif in the serine/arginine protein kinase PSRPK of physarum polycephalum. BMC BIOCHEMISTRY 2009; 10:22. [PMID: 19703313 PMCID: PMC2754491 DOI: 10.1186/1471-2091-10-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2009] [Accepted: 08/25/2009] [Indexed: 11/13/2022]
Abstract
Background Serine/arginine (SR) protein-specific kinases (SRPKs) are conserved in a wide range of organisms, from humans to yeast. Studies showed that SRPKs can regulate the nuclear import of SR proteins in cytoplasm, and regulate the sub-localization of SR proteins in the nucleus. But no nuclear localization signal (NLS) of SRPKs was found. We isolated an SRPK-like protein PSRPK (GenBank accession No. DQ140379) from Physarum polycephalum previously, and identified a NLS of PSRPK in this study. Results We carried out a thorough molecular dissection of the different domains of the PSRPK protein involved in its nuclear localization. By truncation of PSRPK protein, deletion of and single amino acid substitution in a putative NLS and transfection of mammalian cells, we observed the distribution of PSRPK fluorescent fusion protein in mammalian cells using confocal microscopy and found that the protein was mainly accumulated in the nucleus; this indicated that the motif contained a nuclear localization signal (NLS). Further investigation with truncated PSPRK peptides showed that the NLS (318PKKGDKYDKTD328) was localized in the alkaline Ω-loop of a helix-loop-helix motif (HLHM) of the C-terminal conserved domain. If the 318PKKGDK322 sequence was deleted from the loop or K320 was mutated to T320, the PSRPK fluorescent fusion protein could not enter and accumulate in the nucleus. Conclusion This study demonstrated that the 318PKKGDKYDKTD328 peptides localized in the C-terminal conserved domain of PSRPK with the Ω-loop structure could play a crucial role in the NLS function of PSRPK.
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Affiliation(s)
- Shide Liu
- Shenzhen Key Laboratory of Microbial Genetic Engineering and College of Life Science, Shenzhen University, Shenzhen, PR China.
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Liu S, Kang K, Zhang J, Ouyang Q, Zhou Z, Tian S, Xing M. A novel Physarum polycephalum SR protein kinase specifically phosphorylates the RS domain of the human SR protein, ASF/SF2. Acta Biochim Biophys Sin (Shanghai) 2009; 41:657-67. [PMID: 19657567 DOI: 10.1093/abbs/gmp054] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
A 1591-bp cDNA of a serine-rich protein kinase (SRPK)-like protein has been identified in Physarum polycephalum (GenBank accession No. DQ140379). The cDNA contains two repeat sequences at bp 1-153 and bp 395-547. The encoding sequence is 56% homologous to human SRPK1 and is named Physarum SRPK (PSRPK). Consistent with other SRPKs, the consensus motifs of PSRPK are within the two conserved domains (CDs). However, divergent motifs between the N-terminal and CDs are much shorter than the corresponding sequences of other SRPKs. To study the structure and function of this protein, we performed co-expression experiment in Escherichia coli and in vitro phosphorylation assay to investigate the phosphorylation effect of recombinant PSRPK on the human SR protein, ASF/SF2. Western blot analysis showed that PSRPK could phosphorylate ASF/SF2 in E. coli cells. Autoradiographic examination showed that both recombinant PSRPK and a truncated form of PSRPK with a 28-aa deletion at the N-terminus could phosphorylate ASF/SF2 and a truncated form of ASF/SF2 that contains the RS domain. However, these two forms of PSRPK could not phosphorylate a truncated form ASF/SF2 that lacks the RS domain. A truncated form of PSRPK that lacks either of CDs does not have any phosphorylation activity. These results indicated that, like other SRPKs, the phosphorylation site in PSRPK is located within the RS domain of the SR protein and that its phosphorylation activity is closely associated with the two CDs. This study on the structure and function of PSRPK demonstrates that it is a new member of the SRPK family.
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Affiliation(s)
- Shide Liu
- Shenzhen Key Laboratory of Microbial and Genetic Engineering, College of Life Science Shenzhen University, Shenzhen, China
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Kinase domain insertions define distinct roles of CLK kinases in SR protein phosphorylation. Structure 2009; 17:352-62. [PMID: 19278650 PMCID: PMC2667211 DOI: 10.1016/j.str.2008.12.023] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Revised: 12/11/2008] [Accepted: 12/22/2008] [Indexed: 11/29/2022]
Abstract
Splicing requires reversible phosphorylation of serine/arginine-rich (SR) proteins, which direct splice site selection in eukaryotic mRNA. These phosphorylation events are dependent on SR protein (SRPK) and cdc2-like kinase (CLK) families. SRPK1 phosphorylation of splicing factors is restricted by a specific docking interaction whereas CLK activity is less constrained. To understand functional differences between splicing factor targeting kinases, we determined crystal structures of CLK1 and CLK3. Intriguingly, in CLKs the SRPK1 docking site is blocked by insertion of a previously unseen helix αH. In addition, substrate docking grooves present in related mitogen activating protein kinases (MAPKs) are inaccessible due to a CLK specific β7/8-hairpin insert. Thus, the unconstrained substrate interaction together with the determined active-site mediated substrate specificity allows CLKs to complete the functionally important hyperphosphorylation of splicing factors like ASF/SF2. In addition, despite high sequence conservation, we identified inhibitors with surprising isoform specificity for CLK1 over CLK3.
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Ngo JCK, Giang K, Chakrabarti S, Ma CT, Huynh N, Hagopian JC, Dorrestein PC, Fu XD, Adams JA, Ghosh G. A sliding docking interaction is essential for sequential and processive phosphorylation of an SR protein by SRPK1. Mol Cell 2008; 29:563-76. [PMID: 18342604 DOI: 10.1016/j.molcel.2007.12.017] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2007] [Revised: 11/13/2007] [Accepted: 12/21/2007] [Indexed: 01/05/2023]
Abstract
The 2.9 A crystal structure of the core SRPK1:ASF/SF2 complex reveals that the N-terminal half of the basic RS domain of ASF/SF2, which is destined to be phosphorylated, is bound to an acidic docking groove of SRPK1 distal to the active site. Phosphorylation of ASF/SF2 at a single site in the C-terminal end of the RS domain generates a primed phosphoserine that binds to a basic site in the kinase. Biochemical experiments support a directional sliding of the RS peptide through the docking groove to the active site during phosphorylation, which ends with the unfolding of a beta strand of the RRM domain and binding of the unfolded region to the docking groove. We further suggest that the priming of the first serine facilitates directional substrate translocation and efficient phosphorylation.
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Affiliation(s)
- Jacky Chi Ki Ngo
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
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Lukasiewicz R, Velazquez-Dones A, Huynh N, Hagopian J, Fu XD, Adams J, Ghosh G. Structurally unique yeast and mammalian serine-arginine protein kinases catalyze evolutionarily conserved phosphorylation reactions. J Biol Chem 2007; 282:23036-43. [PMID: 17517895 DOI: 10.1074/jbc.m611305200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mammalian serine-arginine (SR) protein, ASF/SF2, contains multiple contiguous RS dipeptides at the C terminus, and approximately 12 of these serines are processively phosphorylated by the SR protein kinase 1 (SRPK1). We have recently shown that a docking motif in ASF/SF2 specifically interacts with a groove in SRPK1, and this interaction is necessary for processive phosphorylation. We previously showed that SRPK1 and its yeast ortholog Sky1p maintain their active conformations using diverse structural strategies. Here we tested if the mechanism of ASF/SF2 phosphorylation by SRPK is evolutionarily conserved. We show that Sky1p forms a stable complex with its heterologous mammalian substrate ASF/SF2 and processively phosphorylates the same sites as SRPK1. We further show that Sky1p utilizes the same docking groove to bind yeast SR-like protein Gbp2p and phosphorylates all three serines present in a contiguous RS dipeptide stretch. However, the mechanism of Gbp2p phosphorylation appears to be non-processive. Thus, there are physical attributes of SR and SR-like substrates that dictate the mechanism of phosphorylation, whereas the ability to processively phosphorylate substrates is inherent to SR protein kinases.
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Affiliation(s)
- Randall Lukasiewicz
- Department of Chemistry & Biochemistry, University of California, San Diego, La Jolla, California 92093-0375, USA
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