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Turner JS, McCabe EA, Kuang KW, Gailey CD, Brautigan DL, Limerick A, Wang EX, Fu Z. The Scaffold Protein KATNIP Enhances CILK1 Control of Primary Cilia. Mol Cell Biol 2023; 43:472-480. [PMID: 37665596 PMCID: PMC10512882 DOI: 10.1080/10985549.2023.2246870] [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: 06/02/2023] [Revised: 08/07/2023] [Accepted: 08/07/2023] [Indexed: 09/05/2023] Open
Abstract
The primary cilium functions as a cellular sensory organelle and signaling antenna that detects and transduces extracellular signals. Mutations in the human gene CILK1 (ciliogenesis associated kinase 1) cause abnormal cilia elongation and faulty Hedgehog signaling, associated with developmental disorders and epilepsy. CILK1 is a protein kinase that requires dual phosphorylation of its TDY motif for activation and its extended C-terminal intrinsically disordered region (IDR) mediates targeting to the basal body and substrate recognition. Proteomics previously identified katanin-interacting protein (KATNIP), also known as KIAA0556, as a CILK1 interacting partner. In this study we discovered that CILK1 colocalizes with KATNIP at the basal body and the CILK1 IDR is sufficient to mediate binding to KATNIP. Deletion analysis of KATNIP shows one of three domains of unknown function (DUF) is required for association with CILK1. KATNIP binding with CILK1 drastically elevated CILK1 protein levels and TDY phosphorylation in cells. This resulted in a profound increase in phosphorylation of known CILK1 substrates and suppression of cilia length. Thus, KATNIP functions as a regulatory subunit of CILK1 that potentiates its actions. This advances our understanding of the molecular basis of control of primary cilia.
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Affiliation(s)
- Jacob S. Turner
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Ellie A. McCabe
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Kevin W. Kuang
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Casey D. Gailey
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - David L. Brautigan
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Ana Limerick
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Elena X. Wang
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Zheng Fu
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
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2
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Mechanisms of Regulation in Intraflagellar Transport. Cells 2022; 11:cells11172737. [PMID: 36078145 PMCID: PMC9454703 DOI: 10.3390/cells11172737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 08/30/2022] [Accepted: 08/31/2022] [Indexed: 11/30/2022] Open
Abstract
Cilia are eukaryotic organelles essential for movement, signaling or sensing. Primary cilia act as antennae to sense a cell’s environment and are involved in a wide range of signaling pathways essential for development. Motile cilia drive cell locomotion or liquid flow around the cell. Proper functioning of both types of cilia requires a highly orchestrated bi-directional transport system, intraflagellar transport (IFT), which is driven by motor proteins, kinesin-2 and IFT dynein. In this review, we explore how IFT is regulated in cilia, focusing from three different perspectives on the issue. First, we reflect on how the motor track, the microtubule-based axoneme, affects IFT. Second, we focus on the motor proteins, considering the role motor action, cooperation and motor-train interaction plays in the regulation of IFT. Third, we discuss the role of kinases in the regulation of the motor proteins. Our goal is to provide mechanistic insights in IFT regulation in cilia and to suggest directions of future research.
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3
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Modulation of Primary Cilia by Alvocidib Inhibition of CILK1. Int J Mol Sci 2022; 23:ijms23158121. [PMID: 35897693 PMCID: PMC9329819 DOI: 10.3390/ijms23158121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/20/2022] [Accepted: 07/20/2022] [Indexed: 11/26/2022] Open
Abstract
The primary cilium provides cell sensory and signaling functions. Cilia structure and function are regulated by ciliogenesis-associated kinase 1 (CILK1). Ciliopathies caused by CILK1 mutations show longer cilia and abnormal Hedgehog signaling. Our study aimed to identify small molecular inhibitors of CILK1 that would enable pharmacological modulation of primary cilia. A previous screen of a chemical library for interactions with protein kinases revealed that Alvocidib has a picomolar binding affinity for CILK1. In this study, we show that Alvocidib potently inhibits CILK1 (IC50 = 20 nM), exhibits selectivity for inhibition of CILK1 over cyclin-dependent kinases 2/4/6 at low nanomolar concentrations, and induces CILK1-dependent cilia elongation. Our results support the use of Alvocidib to potently and selectively inhibit CILK1 to modulate primary cilia.
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Tsutsumi R, Chaya T, Tsujii T, Furukawa T. The carboxyl-terminal region of SDCCAG8 comprises a functional module essential for cilia formation as well as organ development and homeostasis. J Biol Chem 2022; 298:101686. [PMID: 35131266 PMCID: PMC8902618 DOI: 10.1016/j.jbc.2022.101686] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 01/28/2022] [Accepted: 02/01/2022] [Indexed: 02/06/2023] Open
Abstract
In humans, ciliary dysfunction causes ciliopathies, which present as multiple organ defects, including developmental and sensory abnormalities. Sdccag8 is a centrosomal/basal body protein essential for proper cilia formation. Gene mutations in SDCCAG8 have been found in patients with ciliopathies manifesting a broad spectrum of symptoms, including hypogonadism. Among these mutations, several that are predicted to truncate the SDCCAG8 carboxyl (C) terminus are also associated with such symptoms; however, the underlying mechanisms are poorly understood. In the present study, we identified the Sdccag8 C-terminal region (Sdccag8-C) as a module that interacts with the ciliopathy proteins, Ick/Cilk1 and Mak, which were shown to be essential for the regulation of ciliary protein trafficking and cilia length in mammals in our previous studies. We found that Sdccag8-C is essential for Sdccag8 localization to centrosomes and cilia formation in cultured cells. We then generated a mouse mutant in which Sdccag8-C was truncated (Sdccag8ΔC/ΔC mice) using a CRISPR-mediated stop codon knock-in strategy. In Sdccag8ΔC/ΔC mice, we observed abnormalities in cilia formation and ciliopathy-like organ phenotypes, including cleft palate, polydactyly, retinal degeneration, and cystic kidney, which partially overlapped with those previously observed in Ick- and Mak-deficient mice. Furthermore, Sdccag8ΔC/ΔC mice exhibited a defect in spermatogenesis, which was a previously uncharacterized phenotype of Sdccag8 dysfunction. Together, these results shed light on the molecular and pathological mechanisms underlying ciliopathies observed in patients with SDCCAG8 mutations and may advance our understanding of protein–protein interaction networks involved in cilia development.
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5
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Abraham SP, Nita A, Krejci P, Bosakova M. Cilia kinases in skeletal development and homeostasis. Dev Dyn 2021; 251:577-608. [PMID: 34582081 DOI: 10.1002/dvdy.426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 09/22/2021] [Accepted: 09/22/2021] [Indexed: 11/08/2022] Open
Abstract
Primary cilia are dynamic compartments that regulate multiple aspects of cellular signaling. The production, maintenance, and function of cilia involve more than 1000 genes in mammals, and their mutations disrupt the ciliary signaling which manifests in a plethora of pathological conditions-the ciliopathies. Skeletal ciliopathies are genetic disorders affecting the development and homeostasis of the skeleton, and encompass a broad spectrum of pathologies ranging from isolated polydactyly to lethal syndromic dysplasias. The recent advances in forward genetics allowed for the identification of novel regulators of skeletogenesis, and revealed a growing list of ciliary proteins that are critical for signaling pathways implicated in bone physiology. Among these, a group of protein kinases involved in cilia assembly, maintenance, signaling, and disassembly has emerged. In this review, we summarize the functions of cilia kinases in skeletal development and disease, and discuss the available and upcoming treatment options.
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Affiliation(s)
- Sara P Abraham
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Alexandru Nita
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Pavel Krejci
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic.,Institute of Animal Physiology and Genetics of the CAS, Brno, Czech Republic.,International Clinical Research Center, St. Anne's University Hospital, Brno, Czech Republic
| | - Michaela Bosakova
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic.,Institute of Animal Physiology and Genetics of the CAS, Brno, Czech Republic.,International Clinical Research Center, St. Anne's University Hospital, Brno, Czech Republic
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6
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Chaya T, Furukawa T. Post-translational modification enzymes as key regulators of ciliary protein trafficking. J Biochem 2021; 169:633-642. [PMID: 33681987 PMCID: PMC8423421 DOI: 10.1093/jb/mvab024] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 02/24/2021] [Indexed: 12/14/2022] Open
Abstract
Primary cilia are evolutionarily conserved microtubule-based organelles that protrude from the surface of almost all cell types and decode a variety of extracellular stimuli. Ciliary dysfunction causes human diseases named ciliopathies, which span a wide range of symptoms, such as developmental and sensory abnormalities. The assembly, disassembly, maintenance and function of cilia rely on protein transport systems including intraflagellar transport (IFT) and lipidated protein intraflagellar targeting (LIFT). IFT is coordinated by three multisubunit protein complexes with molecular motors along the ciliary axoneme, while LIFT is mediated by specific chaperones that directly recognize lipid chains. Recently, it has become clear that several post-translational modification enzymes play crucial roles in the regulation of IFT and LIFT. Here, we review our current understanding of the roles of these post-translational modification enzymes in the regulation of ciliary protein trafficking as well as their regulatory mechanisms, physiological significance and involvement in human diseases.
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Affiliation(s)
- Taro Chaya
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Osaka, 565-0871, Japan
| | - Takahisa Furukawa
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Osaka, 565-0871, Japan
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Gailey CD, Wang EJ, Jin L, Ahmadi S, Brautigan DL, Li X, Xu W, Scott MM, Fu Z. Phosphosite T674A mutation in kinesin family member 3A fails to reproduce tissue and ciliary defects characteristic of CILK1 loss of function. Dev Dyn 2021; 250:263-273. [PMID: 32935890 PMCID: PMC8460152 DOI: 10.1002/dvdy.252] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 09/10/2020] [Accepted: 09/11/2020] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Kinesin family member 3A (KIF3A) is a molecular motor protein in the heterotrimeric kinesin-2 complex that drives anterograde intraflagellar transport. This process plays a pivotal role in both biogenesis and maintenance of the primary cilium that supports tissue development. Ciliogenesis associated kinase 1 (CILK1) phosphorylates human KIF3A at Thr672. CILK1 loss of function causes ciliopathies that manifest profound and multiplex developmental defects, including hydrocephalus, polydactyly, shortened and hypoplastic bones and alveoli airspace deficiency, leading to perinatal lethality. Prior studies have raised the hypothesis that CILK1 phosphorylation of KIF3A is critical for its regulation of organ development. RESULTS We produced a mouse model with phosphorylation site Thr674 in mouse Kif3a mutated to Ala. Kif3a T674A homozygotes are viable and exhibit no skeletal and brain abnormalities, and only mildly reduced airspace in alveoli. Mouse embryonic fibroblasts carrying Kif3a T674A mutation show a normal rate of ciliation and a moderate increase in cilia length. CONCLUSION These results indicate that eliminating Kif3a Thr674 phosphorylation by Cilk1 is insufficient to reproduce the severe developmental defects in ciliopathies caused by Cilk1 loss of function. This suggests KIF3A-Thr672 phosphorylation by CILK1 is not essential for tissue development and other substrates are involved in CILK1 ciliopathies.
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Affiliation(s)
- Casey D. Gailey
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Eric J. Wang
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Li Jin
- Department of Orthopedic Surgery, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Sean Ahmadi
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia
| | - David L. Brautigan
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia
- NCI designated Cancer Center, Cancer Biology Program, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Xudong Li
- Department of Orthopedic Surgery, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Wenhao Xu
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Michael M. Scott
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Zheng Fu
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia
- NCI designated Cancer Center, Cancer Biology Program, University of Virginia School of Medicine, Charlottesville, Virginia
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Nakamura K, Noguchi T, Takahara M, Omori Y, Furukawa T, Katoh Y, Nakayama K. Anterograde trafficking of ciliary MAP kinase-like ICK/CILK1 by the intraflagellar transport machinery is required for intraciliary retrograde protein trafficking. J Biol Chem 2020; 295:13363-13376. [PMID: 32732286 PMCID: PMC7504932 DOI: 10.1074/jbc.ra120.014142] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 07/01/2020] [Indexed: 12/14/2022] Open
Abstract
ICK (also known as CILK1) is a mitogen-activated protein kinase-like kinase localized at the ciliary tip. Its deficiency is known to result in the elongation of cilia and causes ciliopathies in humans. However, little is known about how ICK is transported to the ciliary tip. We here show that the C-terminal noncatalytic region of ICK interacts with the intraflagellar transport (IFT)-B complex of the IFT machinery and participates in its transport to the ciliary tip. Furthermore, total internal reflection fluorescence microscopy demonstrated that ICK undergoes bidirectional movement within cilia, similarly to IFT particles. Analysis of ICK knockout cells demonstrated that ICK deficiency severely impairs the retrograde trafficking of IFT particles and ciliary G protein-coupled receptors. In addition, we found that in ICK knockout cells, ciliary proteins are accumulated at the bulged ciliary tip, which appeared to be torn off and released into the environment as an extracellular vesicle. The exogenous expression of various ICK constructs in ICK knockout cells indicated that the IFT-dependent transport of ICK, as well as its kinase activity and phosphorylation at the canonical TDY motif, is essential for ICK function. Thus, we unequivocally show that ICK transported to the ciliary tip is required for retrograde ciliary protein trafficking and consequently for normal ciliary function.
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Affiliation(s)
- Kentaro Nakamura
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Tatsuro Noguchi
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Mariko Takahara
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Yoshihiro Omori
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Suita, Osaka, Japan
| | - Takahisa Furukawa
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Suita, Osaka, Japan
| | - Yohei Katoh
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan.
| | - Kazuhisa Nakayama
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan.
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Wang EJ, Gailey CD, Brautigan DL, Fu Z. Functional Alterations in Ciliogenesis-Associated Kinase 1 (CILK1) that Result from Mutations Linked to Juvenile Myoclonic Epilepsy. Cells 2020; 9:cells9030694. [PMID: 32178256 PMCID: PMC7140639 DOI: 10.3390/cells9030694] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 03/09/2020] [Accepted: 03/11/2020] [Indexed: 12/30/2022] Open
Abstract
Ciliopathies are a group of human genetic disorders associated with mutations that give rise to the dysfunction of primary cilia. Ciliogenesis-associated kinase 1 (CILK1), formerly known as intestinal cell kinase (ICK), is a conserved serine and threonine kinase that restricts primary (non-motile) cilia formation and length. Mutations in CILK1 are associated with ciliopathies and are also linked to juvenile myoclonic epilepsy (JME). However, the effects of the JME-related mutations in CILK1 on kinase activity and CILK1 function are unknown. Here, we report that JME pathogenic mutations in the CILK1 N-terminal kinase domain abolish kinase activity, evidenced by the loss of phosphorylation of kinesin family member 3A (KIF3A) at Thr672, while JME mutations in the C-terminal non-catalytic domain (CTD) have little effect on KIF3A phosphorylation. Although CILK1 variants in the CTD retain catalytic activity, they nonetheless lose the ability to restrict cilia length and also gain function in promoting ciliogenesis. We show that wild type CILK1 predominantly localizes to the base of the primary cilium; in contrast, JME variants of CILK1 are distributed along the entire axoneme of the primary cilium. These results demonstrate that JME pathogenic mutations perturb CILK1 function and intracellular localization. These CILK1 variants affect the primary cilium, independent of CILK1 phosphorylation of KIF3A. Our findings suggest that CILK1 mutations linked to JME result in alterations of primary cilia formation and homeostasis.
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Affiliation(s)
- Eric J. Wang
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; (E.J.W.); (C.D.G.)
| | - Casey D. Gailey
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; (E.J.W.); (C.D.G.)
| | - David L. Brautigan
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA;
- NCI-Designated Cancer Center, Cancer Biology Program, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Zheng Fu
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; (E.J.W.); (C.D.G.)
- NCI-Designated Cancer Center, Cancer Biology Program, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
- Correspondence: ; Tel.: +1-434-9823-204
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10
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Activation of sonic hedgehog signaling by a Smoothened agonist restores congenital defects in mouse models of endocrine-cerebro-osteodysplasia syndrome. EBioMedicine 2019; 49:305-317. [PMID: 31662288 PMCID: PMC6945271 DOI: 10.1016/j.ebiom.2019.10.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 09/30/2019] [Accepted: 10/09/2019] [Indexed: 12/13/2022] Open
Abstract
Background Endocrine-cerebro-osteodysplasia (ECO) syndrome is a genetic disorder associated with congenital defects of the endocrine, cerebral, and skeletal systems in humans. ECO syndrome is caused by mutations of the intestinal cell kinase (ICK) gene, which encodes a mitogen-activated protein (MAP) kinase-related kinase that plays a critical role in controlling the length of primary cilia. Lack of ICK function disrupts transduction of sonic hedgehog (SHH) signaling, which is important for development and homeostasis in humans and mice. Craniofacial structure abnormalities, such as cleft palate, are one of the most common defects observed in ECO syndrome patients, but the role of ICK in palatal development has not been studied. Methods Using Ick-mutant mice, we investigated the mechanisms by which ICK function loss causes cleft palate and examined pharmacological rescue of the congenital defects. Findings SHH signaling was compromised with abnormally elongated primary cilia in the developing palate of Ick-mutant mice. Cell proliferation was significantly decreased, resulting in failure of palatal outgrowth, although palatal adhesion and fusion occurred normally. We thus attempted to rescue the congenital palatal defects of Ick mutants by pharmacological activation of SHH signaling. Treatment of Ick-mutant mice with an agonist for Smoothened (SAG) rescued several congenital defects, including cleft palate. Interpretations The recovery of congenital defects by pharmacological intervention in the mouse models for ECO syndrome highlights prenatal SHH signaling modulation as a potential therapeutic measure to overcome congenital defects of ciliopathies.
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Candelori A, Yamamoto TG, Iwamoto M, Montani M, Amici A, Vallesi A. Subcellular Targeting of the Euplotes raikovi Kinase Er-MAPK1, as Revealed by Expression in Different Cell Systems. Front Cell Dev Biol 2019; 7:244. [PMID: 31681773 PMCID: PMC6811501 DOI: 10.3389/fcell.2019.00244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 10/04/2019] [Indexed: 11/13/2022] Open
Abstract
In the ciliate Euplotes raikovi, a 631-amino acid Er-MAPK1 protein kinase was found to localize in nucleoli of the transcriptionally active nucleus (macronucleus) and act as a key component of an autocrine, cell-growth promoting self-signaling mechanism. While its 283-amino acid N-terminal domain includes all the structural specificities of the mitogen-activated protein kinases required for a catalytic function, the 348-amino acid C-terminal domain is structurally unique with undetermined functions. By expressing the two Er-MAPK1 domains tagged with the green fluorescent protein in mammalian fibroblasts, the yeast Schizosaccharomyces pombe and the ciliate Tetrahymena thermophila, evidence was obtained that the C-terminal domain contains all the sequence information responsible for the Er-MAPK1 subcellular localization. However, in fibroblasts and S. pombe this information determined a nucleolar localization of the GFP-tagged C-terminal domain, and a ciliary localization in T. thermophila. In the light of these findings, the Er-MAPK1 localization in E. raikovi was re-examined via immunoreactions and shown to be ciliary besides that nuclear, as is the case for the mammalian intestinal cell kinase with which the Er-MAPK1 N-terminal domain shares a strong sequence identity and a catalytic function.
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Affiliation(s)
- Annalisa Candelori
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Takaharu G Yamamoto
- Advanced ICT Research Institute, National Institute of Information and Communications Technology, Kobe, Japan
| | - Masaaki Iwamoto
- Advanced ICT Research Institute, National Institute of Information and Communications Technology, Kobe, Japan
| | - Maura Montani
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Augusto Amici
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Adriana Vallesi
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
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12
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Fu Z, Gailey CD, Wang EJ, Brautigan DL. Ciliogenesis associated kinase 1: targets and functions in various organ systems. FEBS Lett 2019; 593:2990-3002. [PMID: 31506943 DOI: 10.1002/1873-3468.13600] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 08/22/2019] [Accepted: 09/04/2019] [Indexed: 12/12/2022]
Abstract
Ciliogenesis associated kinase 1 (CILK1) was previously known as intestinal cell kinase because it was cloned from that origin. However, CILK1 is now recognized as a widely expressed and highly conserved serine/threonine protein kinase. Mutations in the human CILK1 gene have been associated with ciliopathies, a group of human genetic disorders with defects in the primary cilium. In mice, both Cilk1 knock-out and Cilk1 knock-in mutations have recapitulated human ciliopathies. Thus, CILK1 has a fundamental role in the function of the cilium. Several candidate substrates have been proposed for CILK1 and the challenge is to relate these to the mutant phenotypes. In this review, we summarize what is known about CILK1 functions and targets, and discuss gaps in current knowledge that motivate further experimentation to fully understand the role of CILK1 in organ development in humans.
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Affiliation(s)
- Zheng Fu
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Casey D Gailey
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Eric J Wang
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - David L Brautigan
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, USA
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13
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Oh YS, Wang EJ, Gailey CD, Brautigan DL, Allen BL, Fu Z. Ciliopathy-Associated Protein Kinase ICK Requires Its Non-Catalytic Carboxyl-Terminal Domain for Regulation of Ciliogenesis. Cells 2019; 8:cells8070677. [PMID: 31277411 PMCID: PMC6678984 DOI: 10.3390/cells8070677] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 07/01/2019] [Accepted: 07/02/2019] [Indexed: 01/08/2023] Open
Abstract
Loss-of-function mutations in the human ICK (intestinal cell kinase) gene cause dysfunctional primary cilia and perinatal lethality which are associated with human ciliopathies. The enzyme that we herein call CAPK (ciliopathy-associated protein kinase) is a serine/threonine protein kinase that has a highly conserved MAPK-like N-terminal catalytic domain and an unstructured C-terminal domain (CTD) whose functions are completely unknown. In this study, we demonstrate that truncation of the CTD impairs the ability of CAPK to interact with and phosphorylate its substrate, kinesin family member 3A (KIF3A). We also find that deletion of the CTD of CAPK compromises both localization to the primary cilium and negative regulation of ciliogenesis. Thus, CAPK substrate recognition, ciliary targeting, and ciliary function depend on the non-catalytic CTD of the protein which is predicted to be intrinsically disordered.
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Affiliation(s)
- Yoon Seon Oh
- Department of Pharmacology, University of Virginia Medical School, Charlottesville, VA 22908, USA
| | - Eric J Wang
- Department of Pharmacology, University of Virginia Medical School, Charlottesville, VA 22908, USA
| | - Casey D Gailey
- Department of Pharmacology, University of Virginia Medical School, Charlottesville, VA 22908, USA
| | - David L Brautigan
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia Medical School, Charlottesville, VA 22908, USA
- Center for Cell Signaling, University of Virginia Medical School, Charlottesville, VA 22908, USA
| | - Benjamin L Allen
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Zheng Fu
- Department of Pharmacology, University of Virginia Medical School, Charlottesville, VA 22908, USA.
- Center for Cell Signaling, University of Virginia Medical School, Charlottesville, VA 22908, USA.
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Enriched expression of the ciliopathy gene Ick in cell proliferating regions of adult mice. Gene Expr Patterns 2018; 29:18-23. [DOI: 10.1016/j.gep.2018.04.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 04/03/2018] [Accepted: 04/06/2018] [Indexed: 01/27/2023]
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15
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Tong Y, Park S, Wu D, Harris TE, Moskaluk CA, Brautigan DL, Fu Z. Modulation of GSK3β autoinhibition by Thr-7 and Thr-8. FEBS Lett 2018; 592:537-546. [PMID: 29377106 DOI: 10.1002/1873-3468.12990] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 01/16/2018] [Accepted: 01/19/2018] [Indexed: 11/08/2022]
Abstract
Glycogen synthase kinase 3β (GSK-3β) is a pivotal signaling node that regulates a myriad of cellular functions and is deregulated in many pathological conditions, making it an attractive therapeutic target. Inhibitory Ser-9 phosphorylation of GSK3β by AKT is an important mechanism for negative regulation of GSK3β activity upon insulin stimulation. Here, we report that Thr-7 and Thr-8 residues located in the AKT/PKB substrate consensus sequence on GSK3β are essential for insulin-stimulated Ser-9 phosphorylation in vivo and for GSK3β inactivation. Intestinal cell kinase (ICK) phosphorylates GSK3β Thr-7 in vitro and in vivo. Thr-8 phosphorylation partially inhibits GSK3β, but Thr-7 phosphorylation promotes GSK3β activity and blocks phospho-Ser-9-dependent GSK3β autoinhibition. Our findings uncover novel mechanistic and signaling inputs involved in the autoinhibition of GSK3β.
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Affiliation(s)
- Yixin Tong
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA.,Gastrointestinal Surgery Center, Tongji Hospital, Huazhong University of Science & Technology, Wuhan, China
| | - Sohyun Park
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Di Wu
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Thurl E Harris
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | | | - David L Brautigan
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Zheng Fu
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
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16
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Tong Y, Park SH, Wu D, Xu W, Guillot SJ, Jin L, Li X, Wang Y, Lin CS, Fu Z. An essential role of intestinal cell kinase in lung development is linked to the perinatal lethality of human ECO syndrome. FEBS Lett 2017; 591:1247-1257. [PMID: 28380258 DOI: 10.1002/1873-3468.12644] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 03/25/2017] [Accepted: 03/31/2017] [Indexed: 01/03/2023]
Abstract
Human endocrine-cerebro-osteodysplasia (ECO) syndrome, caused by the loss-of-function mutation R272Q in the intestinal cell kinase (ICK) gene, is a neonatal-lethal developmental disorder. To elucidate the molecular basis of ECO syndrome, we constructed an Ick R272Q knock-in mouse model that recapitulates ECO pathological phenotypes. Newborns bearing Ick R272Q homozygous mutations die at birth due to respiratory distress. Ick mutant lungs exhibit not only impaired branching morphogenesis associated with reduced mesenchymal proliferation but also significant airspace deficiency in primitive alveoli concomitant with abnormal interstitial mesenchymal differentiation. ICK dysfunction induces elongated primary cilia and perturbs ciliary Hedgehog signaling and autophagy during lung sacculation. Our study identifies an essential role for ICK in lung development and advances the mechanistic understanding of ECO syndrome.
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Affiliation(s)
- Yixin Tong
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA.,The Gastrointestinal Surgery Center, Tongji Hospital, Huazhong University of Science & Technology, Hubei, China
| | - So Hyun Park
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Di Wu
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Wenhao Xu
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Stacey J Guillot
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Li Jin
- Department of Orthopaedic Surgery, University of Virginia, Charlottesville, VA, USA
| | - Xudong Li
- Department of Orthopaedic Surgery, University of Virginia, Charlottesville, VA, USA
| | - Yalin Wang
- Department of Cell Biology, University of Virginia, Charlottesville, VA, USA
| | - Chyuan-Sheng Lin
- Departments of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Zheng Fu
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
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17
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Ick Ciliary Kinase Is Essential for Planar Cell Polarity Formation in Inner Ear Hair Cells and Hearing Function. J Neurosci 2017; 37:2073-2085. [PMID: 28115485 DOI: 10.1523/jneurosci.3067-16.2017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 01/06/2017] [Accepted: 01/11/2017] [Indexed: 11/21/2022] Open
Abstract
Cellular asymmetries play crucial roles in development and organ function. The planar cell polarity (PCP) signaling pathway is involved in the establishment of cellular asymmetry within the plane of a cell sheet. Inner ear sensory hair cells (HCs), which have several rows of staircase-like stereocilia and one kinocilium located at the vertex of the stereocilia protruding from the apical surface of each HC, exhibit a typical form of PCP. Although connections between cilia and PCP signaling in vertebrate development have been reported, their precise nature is not well understood. During inner ear development, several ciliary proteins are known to play a role in PCP formation. In the current study, we investigated a functional role for intestinal cell kinase (Ick), which regulates intraflagellar transport (IFT) at the tip of cilia, in the mouse inner ear. A lack of Ick in the developing inner ear resulted in PCP defects in the cochlea, including misorientation or misshaping of stereocilia and aberrant localization of the kinocilium and basal body in the apical and middle turns, leading to auditory dysfunction. We also observed abnormal ciliary localization of Ift88 in both HCs and supporting cells. Together, our results show that Ick ciliary kinase is essential for PCP formation in inner ear HCs, suggesting that ciliary transport regulation is important for PCP signaling.SIGNIFICANCE STATEMENT The cochlea in the inner ear is the hearing organ. Planar cell polarity (PCP) in hair cells (HCs) in the cochlea is essential for mechanotransduction and refers to the asymmetric structure consisting of stereociliary bundles and the kinocilium on the apical surface of the cell body. We reported previously that a ciliary kinase, Ick, regulates intraflagellar transport (IFT). Here, we found that loss of Ick leads to abnormal localization of the IFT component in kinocilia, PCP defects in HCs, and hearing dysfunction. Our study defines the association of ciliary transport regulation with PCP formation in HCs and hearing function.
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18
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Phipps AI, Passarelli MN, Chan AT, Harrison TA, Jeon J, Hutter CM, Berndt SI, Brenner H, Caan BJ, Campbell PT, Chang-Claude J, Chanock SJ, Cheadle JP, Curtis KR, Duggan D, Fisher D, Fuchs CS, Gala M, Giovannucci EL, Hayes RB, Hoffmeister M, Hsu L, Jacobs EJ, Jansen L, Kaplan R, Kap EJ, Maughan TS, Potter JD, Schoen RE, Seminara D, Slattery ML, West H, White E, Peters U, Newcomb PA. Common genetic variation and survival after colorectal cancer diagnosis: a genome-wide analysis. Carcinogenesis 2015; 37:87-95. [PMID: 26586795 DOI: 10.1093/carcin/bgv161] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 11/13/2015] [Indexed: 12/14/2022] Open
Abstract
Genome-wide association studies have identified several germline single nucleotide polymorphisms (SNPs) significantly associated with colorectal cancer (CRC) incidence. Common germline genetic variation may also be related to CRC survival. We used a discovery-based approach to identify SNPs related to survival outcomes after CRC diagnosis. Genome-wide genotyping arrays were conducted for 3494 individuals with invasive CRC enrolled in six prospective cohort studies (median study-specific follow-up = 4.2-8.1 years). In pooled analyses, we used Cox regression to assess SNP-specific associations with CRC-specific and overall survival, with additional analyses stratified by stage at diagnosis. Top findings were followed-up in independent studies. A P value threshold of P < 5×10(-8) in analyses combining discovery and follow-up studies was required for genome-wide significance. Among individuals with distant-metastatic CRC, several SNPs at 6p12.1, nearest the ELOVL5 gene, were statistically significantly associated with poorer survival, with the strongest associations noted for rs209489 [hazard ratio (HR) = 1.8, P = 7.6×10(-10) and HR = 1.8, P = 3.7×10(-9) for CRC-specific and overall survival, respectively). No SNPs were statistically significantly associated with survival among all cases combined or in cases without distant-metastases. SNPs in 6p12.1/ELOVL5 were associated with survival outcomes in individuals with distant-metastatic CRC, and merit further follow-up for functional significance. Findings from this genome-wide association study highlight the potential importance of genetic variation in CRC prognosis and provide clues to genomic regions of potential interest.
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Affiliation(s)
- Amanda I Phipps
- Epidemiology Department, University of Washington, Seattle, WA 98195, USA.,Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Michael N Passarelli
- Epidemiology Department, University of Washington, Seattle, WA 98195, USA.,Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Andrew T Chan
- Division of Gastroenterology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.,Channing Division of Network Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Tabitha A Harrison
- Public Health Sciences Division , Fred Hutchinson Cancer Research Center , Seattle , WA 98109 , USA
| | - Jihyoun Jeon
- Public Health Sciences Division , Fred Hutchinson Cancer Research Center , Seattle , WA 98109 , USA
| | - Carolyn M Hutter
- Public Health Sciences Division , Fred Hutchinson Cancer Research Center , Seattle , WA 98109 , USA
| | - Sonja I Berndt
- Division of Cancer Epidemiology and Genetics , National Cancer Institute , National Institutes of Health , Bethesda , MD 20892 , USA
| | - Hermann Brenner
- Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany.,German Cancer Consortium (DKTK), Heidelberg 69120, Germany
| | - Bette J Caan
- Division of Research , Kaiser Permanente Medical Care Program of Northern California , Oakland , CA 94612 , USA
| | - Peter T Campbell
- Epidemiology Research Program , American Cancer Society , Atlanta , GA 30303 , USA
| | - Jenny Chang-Claude
- Division of Cancer Epidemiology , Unit of Genetic Epidemiology , German Cancer Research Center (DKFZ) , Heidelberg 69120 , Germany
| | - Stephen J Chanock
- Division of Cancer Epidemiology and Genetics , National Cancer Institute , National Institutes of Health , Bethesda , MD 20892 , USA
| | - Jeremy P Cheadle
- Institute of Cancer and Genetics , School of Medicine , Cardiff University , Cardiff CF14 4XN , UK
| | - Keith R Curtis
- Public Health Sciences Division , Fred Hutchinson Cancer Research Center , Seattle , WA 98109 , USA
| | - David Duggan
- Translational Genomics Research Institute , Phoenix , AZ 85004 , USA
| | - David Fisher
- MRC Clinical Trials Unit , University College London , Aviation House , London WC2B 6NH , UK
| | - Charles S Fuchs
- Channing Division of Network Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA.,Department of Medical Oncology, Dana Farber Cancer Institute, Boston, MA 02215, USA
| | - Manish Gala
- Harvard School of Public Health , Boston , MA 02115 , USA
| | - Edward L Giovannucci
- Channing Division of Network Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA.,Harvard School of Public Health, Boston, MA 02115, USA
| | - Richard B Hayes
- Division of Epidemiology , Department of Population Health , New York University School of Medicine , New York , NY 10016 , USA
| | | | - Li Hsu
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.,Biostatistics Department, University of Washington, Seattle, WA 98195, USA
| | - Eric J Jacobs
- Division of Cancer Epidemiology , Unit of Genetic Epidemiology , German Cancer Research Center (DKFZ) , Heidelberg 69120 , Germany
| | - Lina Jansen
- Division of Clinical Epidemiology and Aging Research , German Cancer Research Center (DKFZ) , Heidelberg 69120 , Germany
| | - Richard Kaplan
- MRC Clinical Trials Unit , University College London , Aviation House , London WC2B 6NH , UK
| | - Elisabeth J Kap
- Division of Cancer Epidemiology , Unit of Genetic Epidemiology , German Cancer Research Center (DKFZ) , Heidelberg 69120 , Germany
| | - Timothy S Maughan
- Gray Institute for Radiation Oncology and Biology , University of Oxford , Oxford OX3 7DQ , UK
| | - John D Potter
- Epidemiology Department, University of Washington, Seattle, WA 98195, USA.,Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.,Centre for Public Health Research, Massey University, Wellington 6140, New Zealand
| | - Robert E Schoen
- Department of Medicine and Epidemiology , University of Pittsburgh Medical Center , Pittsburgh , PA 15213 , USA
| | - Daniela Seminara
- Division of Cancer Control and Population Sciences , National Cancer Institute , National Institutes of Health , Bethesda , MD 20892 , USA , and
| | - Martha L Slattery
- Department of Internal Medicine , University of Utah Health Sciences Center , Salt Lake City , UT 84132 , USA
| | - Hannah West
- Institute of Cancer and Genetics , School of Medicine , Cardiff University , Cardiff CF14 4XN , UK
| | - Emily White
- Epidemiology Department, University of Washington, Seattle, WA 98195, USA.,Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Ulrike Peters
- Epidemiology Department, University of Washington, Seattle, WA 98195, USA.,Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Polly A Newcomb
- Epidemiology Department, University of Washington, Seattle, WA 98195, USA.,Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
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19
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Verma PK, El-Harouni AA. Review of literature: genes related to postaxial polydactyly. Front Pediatr 2015; 3:8. [PMID: 25717468 PMCID: PMC4324078 DOI: 10.3389/fped.2015.00008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 01/26/2015] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Postaxial polydactyly (PAP) is one of the commonest congenital malformations and usually is associated to several syndromes. There is no primary investigational strategy for PAP cases with single gene disorder in literature. PAP cases with single gene disorder can be classified according to common pathways and molecular basis. Molecular classification may help in diagnostic approach. MATERIALS AND METHODS All single gene disorders associated with PAP reported on PubMed and OMIM are analyzed and classified according to molecular basis. RESULTS Majority of genes related to cilia structure and functions are associated with PAP, so we classified them as ciliopathies and non-ciliopathies groups. Genes related to Shh-Gli3 pathway was the commonest group in non-ciliopathies. CONCLUSION Genes related to cilia are most commonly related to PAP due to their indirect relationship to Shh-Gli3 signaling pathway. Initially, PAP may be the only clinical finding with ciliopathies so those cases need follow up. Proper diagnosis is helpful for management and genetic counseling. Molecular approach may help to define pleiotropy.
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Affiliation(s)
- Prashant Kumar Verma
- Department of Genetic Medicine, Faculty of Medicine, King Abdulaziz University , Jeddah , Saudi Arabia
| | - Ashraf A El-Harouni
- Department of Genetic Medicine, Faculty of Medicine, King Abdulaziz University , Jeddah , Saudi Arabia ; Department of Clinical Genetics, National Research Center , Cairo , Egypt
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20
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Broekhuis JR, Verhey KJ, Jansen G. Regulation of cilium length and intraflagellar transport by the RCK-kinases ICK and MOK in renal epithelial cells. PLoS One 2014; 9:e108470. [PMID: 25243405 PMCID: PMC4171540 DOI: 10.1371/journal.pone.0108470] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 08/25/2014] [Indexed: 01/11/2023] Open
Abstract
Primary cilia are important sensory organelles. They exist in a wide variety of lengths, which could reflect different cell-specific functions. How cilium length is regulated is unclear, but it probably involves intraflagellar transport (IFT), which transports protein complexes along the ciliary axoneme. Studies in various organisms have identified the small, conserved family of ros-cross hybridizing kinases (RCK) as regulators of cilium length. Here we show that Intestinal Cell Kinase (ICK) and MAPK/MAK/MRK overlapping kinase (MOK), two members of this family, localize to cilia of mouse renal epithelial (IMCD-3) cells and negatively regulate cilium length. To analyze the effects of ICK and MOK on the IFT machinery, we set up live imaging of five fluorescently tagged IFT proteins: KIF3B, a subunit of kinesin-II, the main anterograde IFT motor, complex A protein IFT43, complex B protein IFT20, BBSome protein BBS8 and homodimeric kinesin KIF17, whose function in mammalian cilia is unclear. Interestingly, all five proteins moved at ∼0.45 µm/s in anterograde and retrograde direction, suggesting they are all transported by the same machinery. Moreover, GFP tagged ICK and MOK moved at similar velocities as the IFT proteins, suggesting they are part of, or transported by the IFT machinery. Indeed, loss- or gain-of-function of ICK affected IFT speeds: knockdown increased anterograde velocities, whereas overexpression reduced retrograde speed. In contrast, MOK knockdown or overexpression did not affect IFT speeds. Finally, we found that the effects of ICK or MOK knockdown on cilium length and IFT are suppressed by rapamycin treatment, suggesting that these effects require the mTORC1 pathway. Our results confirm the importance of RCK kinases as regulators of cilium length and IFT. However, whereas some of our results suggest a direct correlation between cilium length and IFT speed, other results indicate that cilium length can be modulated independent of IFT speed.
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Affiliation(s)
| | - Kristen J. Verhey
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Gert Jansen
- Department of Cell Biology, Erasmus MC, Rotterdam, the Netherlands
- * E-mail:
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21
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Bolick DT, Chen T, O. Alves LA, Tong Y, Wu D, Joyner LT, Oriá RB, Guerrant RL, Fu Z. Intestinal cell kinase is a novel participant in intestinal cell signaling responses to protein malnutrition. PLoS One 2014; 9:e106902. [PMID: 25184386 PMCID: PMC4153720 DOI: 10.1371/journal.pone.0106902] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 08/08/2014] [Indexed: 01/17/2023] Open
Abstract
Nutritional deficiency and stress can severely impair intestinal architecture, integrity and host immune defense, leading to increased susceptibility to infection and cancer. Although the intestine has an inherent capability to adapt to environmental stress, the molecular mechanisms by which the intestine senses and responds to malnutrition are not completely understood. We hereby report that intestinal cell kinase (ICK), a highly conserved serine/threonine protein kinase, is a novel component of the adaptive cell signaling responses to protein malnutrition in murine small intestine. Using an experimental mouse model, we demonstrated that intestinal ICK protein level was markedly and transiently elevated upon protein deprivation, concomitant with activation of prominent pro-proliferation and pro-survival pathways of Wnt/β-catenin, mammalian target of rapamycin (mTOR), mitogen-activated protein kinase (MAPK), and protein kinase B (PKB/Akt) as well as increased expression of intestinal stem cell markers. Using the human ileocecal epithelial cell line HCT-8 as an invitro model, we further demonstrated that serum starvation was able to induce up-regulation of ICK protein in intestinal epithelial cells in a reversible manner, and that serum albumin partially contributed to this effect. Knockdown of ICK expression in HCT-8 cells significantly impaired cell proliferation and down-regulated active β-catenin signal. Furthermore, reduced ICK expression in HCT-8 cells induced apoptosis through a caspase-dependent mechanism. Taken together, our findings suggest that increased ICK expression/activity in response to protein deprivation likely provides a novel protective mechanism to limit apoptosis and support compensatory mucosal growth under nutritional stress.
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Affiliation(s)
- David T. Bolick
- Department of Medicine, Center for Global Health, Digestive Research Center of Excellence, University of Virginia, Charlottesville, Virginia, United States of America
| | - Tufeng Chen
- Department of Medicine, Center for Global Health, Digestive Research Center of Excellence, University of Virginia, Charlottesville, Virginia, United States of America
- Department of Gastrointestinal Surgery, The Third Affiliated Hospital of Sun Yat-sen University, Guangdong, China
| | - Luís Antonio O. Alves
- Department of Medicine, Center for Global Health, Digestive Research Center of Excellence, University of Virginia, Charlottesville, Virginia, United States of America
| | - Yixin Tong
- Department of Medicine, Center for Global Health, Digestive Research Center of Excellence, University of Virginia, Charlottesville, Virginia, United States of America
- Gastrointestinal Surgery Center, Tongji Hospital, Huazhong University of Science & Technology, Hubei, China
| | - Di Wu
- Department of Medicine, Center for Global Health, Digestive Research Center of Excellence, University of Virginia, Charlottesville, Virginia, United States of America
| | - Linwood T. Joyner
- Department of Medicine, Center for Global Health, Digestive Research Center of Excellence, University of Virginia, Charlottesville, Virginia, United States of America
| | - Reinaldo B. Oriá
- Department of Medicine, Center for Global Health, Digestive Research Center of Excellence, University of Virginia, Charlottesville, Virginia, United States of America
| | - Richard L. Guerrant
- Department of Medicine, Center for Global Health, Digestive Research Center of Excellence, University of Virginia, Charlottesville, Virginia, United States of America
- * E-mail: (ZF); (RLG)
| | - Zheng Fu
- Department of Medicine, Center for Global Health, Digestive Research Center of Excellence, University of Virginia, Charlottesville, Virginia, United States of America
- * E-mail: (ZF); (RLG)
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22
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Intestinal cell kinase, a protein associated with endocrine-cerebro-osteodysplasia syndrome, is a key regulator of cilia length and Hedgehog signaling. Proc Natl Acad Sci U S A 2014; 111:8541-6. [PMID: 24853502 DOI: 10.1073/pnas.1323161111] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Endocrine-cerebro-osteodysplasia (ECO) syndrome is a recessive genetic disorder associated with multiple congenital defects in endocrine, cerebral, and skeletal systems that is caused by a missense mutation in the mitogen-activated protein kinase-like intestinal cell kinase (ICK) gene. In algae and invertebrates, ICK homologs are involved in flagellar formation and ciliogenesis, respectively. However, it is not clear whether this role of ICK is conserved in mammals and how a lack of functional ICK results in the characteristic phenotypes of human ECO syndrome. Here, we generated Ick knockout mice to elucidate the precise role of ICK in mammalian development and to examine the pathological mechanisms of ECO syndrome. Ick null mouse embryos displayed cleft palate, hydrocephalus, polydactyly, and delayed skeletal development, closely resembling ECO syndrome phenotypes. In cultured cells, down-regulation of Ick or overexpression of kinase-dead or ECO syndrome mutant ICK resulted in an elongation of primary cilia and abnormal Sonic hedgehog (Shh) signaling. Wild-type ICK proteins were generally localized in the proximal region of cilia near the basal bodies, whereas kinase-dead ICK mutant proteins accumulated in the distal part of bulged ciliary tips. Consistent with these observations in cultured cells, Ick knockout mouse embryos displayed elongated cilia and reduced Shh signaling during limb digit patterning. Taken together, these results indicate that ICK plays a crucial role in controlling ciliary length and that ciliary defects caused by a lack of functional ICK leads to abnormal Shh signaling, resulting in congenital disorders such as ECO syndrome.
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23
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Chaya T, Omori Y, Kuwahara R, Furukawa T. ICK is essential for cell type-specific ciliogenesis and the regulation of ciliary transport. EMBO J 2014; 33:1227-42. [PMID: 24797473 DOI: 10.1002/embj.201488175] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Cilia and flagella are formed and maintained by intraflagellar transport (IFT) and play important roles in sensing and moving across species. At the distal tip of the cilia/flagella, IFT complexes turn around to switch from anterograde to retrograde transport; however, the underlying regulatory mechanism is unclear. Here, we identified ICK localization at the tip of cilia as a regulator of ciliary transport. In ICK-deficient mice, we found ciliary defects in neuronal progenitor cells with Hedgehog signal defects. ICK-deficient cells formed cilia with mislocalized Hedgehog signaling components. Loss of ICK caused the accumulation of IFT-A, IFT-B, and BBSome components at the ciliary tips. In contrast, overexpression of ICK induced the strong accumulation of IFT-B, but not IFT-A or BBSome components at ciliary tips. In addition, ICK directly phosphorylated Kif3a, while inhibition of this Kif3a phosphorylation affected ciliary formation. Our results suggest that ICK is a Kif3a kinase and essential for proper ciliogenesis in development by regulating ciliary transport at the tip of cilia.
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Affiliation(s)
- Taro Chaya
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research Osaka University, Suita Osaka, Japan JST CREST, Suita Osaka, Japan Department of Developmental Biology, Osaka Bioscience Institute, Suita Osaka, Japan Kyoto University Graduate School of Medicine, Sakyo-ku Kyoto, Japan
| | - Yoshihiro Omori
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research Osaka University, Suita Osaka, Japan JST CREST, Suita Osaka, Japan Department of Developmental Biology, Osaka Bioscience Institute, Suita Osaka, Japan JST PRESTO, Suita Osaka, Japan
| | - Ryusuke Kuwahara
- Research Center for Ultrahigh Voltage Electron Microscopy Osaka University, Ibaraki Osaka, Japan
| | - Takahisa Furukawa
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research Osaka University, Suita Osaka, Japan JST CREST, Suita Osaka, Japan Department of Developmental Biology, Osaka Bioscience Institute, Suita Osaka, Japan
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24
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Distinct expression patterns of ICK/MAK/MOK protein kinases in the intestine implicate functional diversity. PLoS One 2013; 8:e79359. [PMID: 24244486 PMCID: PMC3820702 DOI: 10.1371/journal.pone.0079359] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 09/29/2013] [Indexed: 02/07/2023] Open
Abstract
ICK/MRK (intestinal cell kinase/MAK-related kinase), MAK (male germ cell-associated kinase), and MOK (MAPK/MAK/MRK-overlapping kinase) are closely related serine/threonine protein kinases in the protein kinome. The biological functions and regulatory mechanisms of the ICK/MAK/MOK family are still largely elusive. Despite significant similarities in their catalytic domains, they diverge markedly in the sequence and structural organization of their C-terminal non-catalytic domains, raising the question as to whether they have distinct, overlapping, or redundant biological functions. In order to gain insights into their biological activities and lay a fundamental groundwork for functional studies, we investigated the spatio-temporal distribution patterns and the expression dynamics of ICK/MAK/MOK protein kinases in the intestine. We found that ICK/MAK/MOK proteins display divergent expression patterns along the duodenum-to-colon axis and during postnatal murine development. Furthermore, they are differentially partitioned between intestinal epithelium and mesenchyme. A significant increase in the protein level of ICK, but not MAK, was induced in human primary colon cancer specimens. ICK protein level was up-regulated whereas MOK protein level was down-regulated in mouse intestinal adenomas as compared with their adjacent normal intestinal mucosa. These data suggest distinct roles for ICK/MAK/MOK protein kinases in the regulation of intestinal neoplasia. Taken together, our findings demonstrate that the expressions of ICK/MAK/MOK proteins in the intestinal tract can be differentially and dynamically regulated, implicating a significant functional diversity within this group of protein kinases.
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Yang Y, Roine N, Mäkelä TP. CCRK depletion inhibits glioblastoma cell proliferation in a cilium-dependent manner. EMBO Rep 2013; 14:741-7. [PMID: 23743448 DOI: 10.1038/embor.2013.80] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 05/01/2013] [Accepted: 05/16/2013] [Indexed: 01/09/2023] Open
Abstract
Loss of primary cilia is frequently observed in tumour cells, including glioblastoma cells, and proposed to benefit tumour growth, but a causal link has not been established. Here, we show that CCRK (cell cycle-related kinase) and its substrate ICK (intestinal cell kinase) inhibit ciliogenesis. Depletion of CCRK leads to accumulation of ICK at ciliary tips, altered ciliary transport and inhibition of cell cycle re-entry in NIH3T3 fibroblasts. In glioblastoma cells with deregulated high levels of CCRK, its depletion restores cilia through ICK and an ICK-related kinase MAK, thereby inhibiting glioblastoma cell proliferation. These results indicate that inhibition of ciliogenesis might be a mechanism used by cancer cells to provide a growth advantage.
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Affiliation(s)
- Ying Yang
- Institute of Biotechnology, University of Helsinki, Helsinki 00790, Finland
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Candelori A, Luporini P, Alimenti C, Vallesi A. Characterization and expression of the gene encoding En-MAPK1, an intestinal cell kinase (ICK)-like kinase activated by the autocrine pheromone-signaling loop in the Polar Ciliate, Euplotes nobilii. Int J Mol Sci 2013; 14:7457-67. [PMID: 23552830 PMCID: PMC3645696 DOI: 10.3390/ijms14047457] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 03/21/2013] [Accepted: 03/21/2013] [Indexed: 11/16/2022] Open
Abstract
In the protozoan ciliate Euplotes, a transduction pathway resulting in a mitogenic cell growth response is activated by autocrine receptor binding of cell type-specific, water-borne signaling protein pheromones. In Euplotes raikovi, a marine species of temperate waters, this transduction pathway was previously shown to involve the phosphorylation of a nuclear protein kinase structurally similar to the intestinal-cell and male germ cell-associated kinases described in mammals. In E. nobilii, which is phylogenetically closely related to E. raikovi but inhabits Antarctic and Arctic waters, we have now characterized a gene encoding a structurally homologous kinase. The expression of this gene requires +1 translational frameshifting and a process of intron splicing for the production of the active protein, designated En-MAPK1, which contains amino acid substitutions of potential significance for cold-adaptation.
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Affiliation(s)
- Annalisa Candelori
- Laboratory of Eukaryotic Microbiology and Animal Biology, Department of Environmental and Natural Sciences, University of Camerino, Camerino 62032, Italy.
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Broekhuis JR, Leong WY, Jansen G. Regulation of cilium length and intraflagellar transport. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 303:101-38. [PMID: 23445809 DOI: 10.1016/b978-0-12-407697-6.00003-9] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Primary cilia are highly conserved sensory organelles that extend from the surface of almost all vertebrate cells. The importance of cilia is evident from their involvement in many diseases, called ciliopathies. Primary cilia contain a microtubular axoneme that is used as a railway for transport of both structural components and signaling proteins. This transport machinery is called intraflagellar transport (IFT). Cilia are dynamic organelles whose presence on the cell surface, morphology, length and function are highly regulated. It is clear that the IFT machinery plays an important role in this regulation. However, it is not clear how, for example environmental cues or cell fate decisions are relayed to modulate IFT and cilium morphology or function. This chapter presents an overview of molecules that have been shown to regulate cilium length and IFT. Several examples where signaling modulates IFT and cilium function are used to discuss the importance of these systems for the cell and for understanding of the etiology of ciliopathies.
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Wu D, Chapman JR, Wang L, Harris TE, Shabanowitz J, Hunt DF, Fu Z. Intestinal cell kinase (ICK) promotes activation of mTOR complex 1 (mTORC1) through phosphorylation of Raptor Thr-908. J Biol Chem 2012; 287:12510-9. [PMID: 22356909 DOI: 10.1074/jbc.m111.302117] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Intestinal cell kinase (ICK), named after its cloning origin, the intestine, is actually a ubiquitously expressed and highly conserved serine/threonine protein kinase. Recently we reported that ICK supports cell proliferation and G(1) cell cycle progression. ICK deficiency significantly disrupted the mammalian target of rapamycin (mTOR) complex 1 (mTORC1) signaling events. However, the biological substrates that mediate the downstream signaling effects of ICK in proliferation and the molecular mechanisms by which ICK interacts with mTORC1 are not well defined. Our prior studies also provided biochemical evidence that ICK interacts with the mTOR/Raptor complex in cells and phosphorylates Raptor in vitro. In this report, we investigated whether and how ICK targets Raptor to regulate the activity of mTORC1. Using the ICK substrate consensus sequence [R-P-X-S/T-P/A/T/S], we identified a putative phosphorylation site, RPGT908T, for ICK in human Raptor. By mass spectrometry and a phospho-specific antibody, we showed that Raptor Thr-908 is a novel in vivo phosphorylation site. ICK is able to phosphorylate Raptor Thr-908 both in vitro and in vivo and when Raptor exists in protein complexes with or without mTOR. Although expression of the Raptor T908A mutant did not affect the mTORC1 integrity, it markedly impaired the mTORC1 activation by insulin or by overexpression of the small GTP-binding protein RheB under nutrient starvation. Our findings demonstrate an important role for ICK in modulating the activity of mTORC1 through phosphorylation of Raptor Thr-908 and thus implicate a potential signaling mechanism by which ICK regulates cell proliferation and division.
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Affiliation(s)
- Di Wu
- Department of Medicine, University of Virginia, Charlottesville, Virginia 22908, USA
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Reid DW, Nicchitta CV. Primary role for endoplasmic reticulum-bound ribosomes in cellular translation identified by ribosome profiling. J Biol Chem 2011; 287:5518-27. [PMID: 22199352 DOI: 10.1074/jbc.m111.312280] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
In eukaryotic cells, the spatial regulation of protein expression is frequently conferred through the coupling of mRNA localization and the local control of translation. mRNA localization to the endoplasmic reticulum (ER) is a prominent example of such regulation and serves a ubiquitous role in segregating the synthesis of secretory and integral membrane proteins to the ER. Recent genomic and biochemical studies have now expanded this view to suggest a more substantial role for the ER cellular protein synthesis. We have utilized cell fractionation and ribosome profiling to obtain a genomic survey of the subcellular organization of mRNA translation and report that ribosomal loading of mRNAs, a proxy for mRNA translation, is biased to the ER. Notably, ER-associated mRNAs encoding both cytosolic and topogenic signal-encoding proteins display similar ribosome loading densities, suggesting that ER-associated ribosomes serve a global role in mRNA translation. We propose that the partitioning of mRNAs and their translation between the cytosol and ER compartments may represent a novel mechanism for the post-transcriptional regulation of gene expression.
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Affiliation(s)
- David W Reid
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA
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Lahiry P, Lee LJ, Frey BJ, Rupar CA, Siu VM, Blencowe BJ, Hegele RA. Transcriptional profiling of endocrine cerebro-osteodysplasia using microarray and next-generation sequencing. PLoS One 2011; 6:e25400. [PMID: 21980446 PMCID: PMC3181319 DOI: 10.1371/journal.pone.0025400] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Accepted: 09/02/2011] [Indexed: 12/14/2022] Open
Abstract
Background Transcriptome profiling of patterns of RNA expression is a powerful approach to identify networks of genes that play a role in disease. To date, most mRNA profiling of tissues has been accomplished using microarrays, but next-generation sequencing can offer a richer and more comprehensive picture. Methodology/Principal Findings ECO is a rare multi-system developmental disorder caused by a homozygous mutation in ICK encoding intestinal cell kinase. We performed gene expression profiling using both cDNA microarrays and next-generation mRNA sequencing (mRNA-seq) of skin fibroblasts from ECO-affected subjects. We then validated a subset of differentially expressed transcripts identified by each method using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Finally, we used gene ontology (GO) to identify critical pathways and processes that were abnormal according to each technical platform. Methodologically, mRNA-seq identifies a much larger number of differentially expressed genes with much better correlation to qRT-PCR results than the microarray (r2 = 0.794 and 0.137, respectively). Biologically, cDNA microarray identified functional pathways focused on anatomical structure and development, while the mRNA-seq platform identified a higher proportion of genes involved in cell division and DNA replication pathways. Conclusions/Significance Transcriptome profiling with mRNA-seq had greater sensitivity, range and accuracy than the microarray. The two platforms generated different but complementary hypotheses for further evaluation.
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Affiliation(s)
- Piya Lahiry
- Robarts Research Institute, London, Ontario, Canada
- Department of Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Leo J. Lee
- Banting and Best Department of Medical Research and Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Department of Electrical & Computer Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Brendan J. Frey
- Banting and Best Department of Medical Research and Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Department of Electrical & Computer Engineering, University of Toronto, Toronto, Ontario, Canada
| | - C. Anthony Rupar
- Department of Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
- Department of Pediatrics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
- Children's Health Research Institute, Lawson Health Research Institute, London, Ontario, Canada
| | - Victoria M. Siu
- Department of Pediatrics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
- Children's Health Research Institute, Lawson Health Research Institute, London, Ontario, Canada
| | - Benjamin J. Blencowe
- Banting and Best Department of Medical Research and Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Robert A. Hegele
- Robarts Research Institute, London, Ontario, Canada
- Department of Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
- Department of Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
- * E-mail:
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Häggarth L, Hägglöf C, Jaraj SJ, Wester K, Pontén F, Ostman A, Egevad L. Diagnostic biomarkers of prostate cancer. ACTA ACUST UNITED AC 2010; 45:60-7. [PMID: 21034352 DOI: 10.3109/00365599.2010.526141] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
OBJECTIVE Diagnostic tissue biomarkers for prostate cancer (PC) include basal cell markers and α-methylacyl-coenzyme A-racemase (AMACR), often used in combination. Their sensitivity and specificity are not perfect and there is a need for additional diagnostic biomarkers for PC in cases that are difficult to diagnose on routine stained sections. MATERIAL AND METHODS This study investigated the diagnostic accuracy of three novel tissue biomarkers for PC found through a search in the Human Protein Atlas database ( www.proteinatlas.com ): somatic cytochrome c (CYCS), intestinal cell kinase (ICK) and inhibitor of nuclear factor-κB kinase subunit beta (IKBKB), and compared the results with AMACR. A tissue microarray was constructed from 40 consecutive radical prostatectomy (RP) specimens including benign prostatic tissue, atrophy, high-grade prostatic intraepithelial neoplasia (HGPIN) and PC. Immunoreactivity was scored based on staining intensity and extent. Real-time polymerase chain reaction (PCR) was performed on malignant and benign frozen tissue samples from 32 RP specimens. RESULTS All four biomarkers showed a stronger expression in PC and HGPIN than in benign tissue (p < 0.001). The highest diagnostic accuracy for PC was achieved with ICK and AMACR at 97%. The area under the curve for CYCS, ICK, IKBKB and AMACR was 0.859, 0.997, 0.865 and 0.983, respectively. The presence of mRNA transcripts of the genes was confirmed by real-time PCR in benign and malignant prostatic tissue. CONCLUSIONS AMACR is an accurate diagnostic tissue marker for PC. However, in some PCs AMACR is false negative and a panel of CYCS, ICK and IKBKB may serve as ancillary diagnostic tool.
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Affiliation(s)
- Lars Häggarth
- Department of Oncology and Pathology, Karolinska Institutet, Stockholm, Sweden
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Sturgill TW, Stoddard PB, Cohn SM, Mayo MW. The promoter for intestinal cell kinase is head-to-head with F-Box 9 and contains functional sites for TCF7L2 and FOXA factors. Mol Cancer 2010; 9:104. [PMID: 20459822 PMCID: PMC2876993 DOI: 10.1186/1476-4598-9-104] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Accepted: 05/11/2010] [Indexed: 12/13/2022] Open
Abstract
Background Intestinal cell kinase (ICK; GeneID 22858) is a conserved MAPK and CDK-like kinase that is widely expressed in human tissues. Data from the Cancer Genome Anatomy Project indicated ICK mRNA is increased in cancer, and that its expression correlated with expression of mRNA for an uncharacterized F-box protein, FBX9 (GeneID: 26268). ICK and FBX9 genes are arranged head-to-head on opposite strands, with start sites for transcription separated by ~3.3 kb. We hypothesized ICK and FBX9 are potentially important genes in cancer controlled by a bidirectional promoter. Results We assessed promoter activity of the intergenic region in both orientations in cancer cell lines derived from breast (AU565, SKBR3), colon (HCT-15, KM12), and stomach (AGS) cancers, as well as in embryonic human kidney (HEK293T) cells. The intergenic segment was active in both orientations in all of these lines, and ICK promoter activity was greater than FBX9 promoter activity. Results from deletions and truncations defined a minimal promoter for ICK, and revealed that repressors and enhancers differentially regulate ICK versus FBX9 promoter activity. The ICK promoter contains consensus motifs for several FOX-family transcription factors that align when mouse and human are compared using EMBOSS. FOXA1 and FOXA2 increase luciferase activity of a minimal promoter 10-20 fold in HEK293T cells. Consensus sites for TCF7L2 (TCF4) (Gene Id: 6934) are also present in both mouse and human. The expression of β-catenin increased activity of the minimal promoter ~10 fold. ICK reference mRNAs (NM_014920.3, NM_016513) are expressed in low copy number and increased in some breast cancers, using a ten base tag 5'-TCAACCTTAT-3' specific for both ICK transcripts. Conclusion ICK and FBX9 are divergently transcribed from a bidirectional promoter that is GC-rich and contains a CpG island. A minimal promoter for ICK contains functional sites for β-cateinin/TCF7L2 and FOXA. These data are consistent with functions that have been proposed for ICK in development and in proliferation or survival of some breast and colon cancers.
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Affiliation(s)
- Thomas W Sturgill
- Departments of Pharmacology and Internal Medicine, University of Virginia, 1300 Jefferson Park Avenue, Charlottesville, Virginia 22908, USA.
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Vallesi A, Di Pretoro B, Ballarini P, Apone F, Luporini P. A Novel Protein Kinase from the Ciliate Euplotes raikovi with Close Structural Identity to the Mammalian Intestinal and Male-Germ Cell Kinases: Characterization and Functional Implications in the Autocrine Pheromone Signaling Loop. Protist 2010; 161:250-63. [DOI: 10.1016/j.protis.2009.12.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Accepted: 11/21/2009] [Indexed: 12/01/2022]
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Fu Z, Kim J, Vidrich A, Sturgill TW, Cohn SM. Intestinal cell kinase, a MAP kinase-related kinase, regulates proliferation and G1 cell cycle progression of intestinal epithelial cells. Am J Physiol Gastrointest Liver Physiol 2009; 297:G632-40. [PMID: 19696144 PMCID: PMC2763805 DOI: 10.1152/ajpgi.00066.2009] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Intestinal cell kinase (ICK), originally cloned from the intestine and expressed in the intestinal crypt epithelium, is a highly conserved serine/threonine protein kinase that is similar to mitogen-activated protein kinases (MAPKs) in the catalytic domain and requires dual phosphorylation within a MAPK-like TDY motif for full activation. Despite these similarities to MAPKs, the biological functions of ICK remain unknown. In this study, we report that suppression of ICK expression in cultured intestinal epithelial cells by short hairpin RNA (shRNA) interference significantly impaired cellular proliferation and induced features of gene expression characteristic of colonic or enterocytic differentiation. Downregulation of ICK altered expression of cell cycle regulators (cyclin D1, c-Myc, and p21(Cip1/WAF1)) of G(1)-S transition, consistent with the G(1) cell cycle delay induced by ICK shRNA. ICK deficiency also led to a significant decrease in the expression and/or activity of p70 ribosomal protein S6 kinase (S6K1) and eukaryotic initiation factor 4E (eIF4E), concomitant with reduced expression of their upstream regulators, the mammalian target of rapamycin (mTOR) and the regulatory associated protein of mTOR (Raptor). Furthermore, ICK interacts with the mTOR/Raptor complex in vivo and phosphorylates Raptor in vitro. These results suggest that disrupting ICK function may downregulate protein translation of specific downstream targets of eIF4E and S6K1 such as cyclin D1 and c-Myc through the mTOR/Raptor signaling pathway. Taken together, our findings demonstrate an important role for ICK in proliferation and differentiation of intestinal epithelial cells.
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Affiliation(s)
- Zheng Fu
- Digestive Health Center of Excellence, Univ. of Virginia Health System, PO Box 800708, Charlottesville, VA 22908, USA.
| | - Jungeun Kim
- 1Digestive Health Center of Excellence and Department of Medicine and
| | - Alda Vidrich
- 1Digestive Health Center of Excellence and Department of Medicine and
| | - Thomas W. Sturgill
- 2Department of Pharmacology, University of Virginia, Charlottesville, Virginia
| | - Steven M. Cohn
- 1Digestive Health Center of Excellence and Department of Medicine and
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Bayram Ö, Sari F, Braus GH, Irniger S. The protein kinase ImeB is required for light-mediated inhibition of sexual development and for mycotoxin production inAspergillus nidulans. Mol Microbiol 2009; 71:1278-95. [DOI: 10.1111/j.1365-2958.2009.06606.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Lahiry P, Wang J, Robinson JF, Turowec JP, Litchfield DW, Lanktree MB, Gloor GB, Puffenberger EG, Strauss KA, Martens MB, Ramsay DA, Rupar CA, Siu V, Hegele RA. A multiplex human syndrome implicates a key role for intestinal cell kinase in development of central nervous, skeletal, and endocrine systems. Am J Hum Genet 2009; 84:134-47. [PMID: 19185282 DOI: 10.1016/j.ajhg.2008.12.017] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2008] [Revised: 12/19/2008] [Accepted: 12/22/2008] [Indexed: 12/22/2022] Open
Abstract
Six infants in an Old Order Amish pedigree were observed to be affected with endocrine-cerebro-osteodysplasia (ECO). ECO is a previously unidentified neonatal lethal recessive disorder with multiple anomalies involving the endocrine, cerebral, and skeletal systems. Autozygosity mapping and sequencing identified a previously unknown missense mutation, R272Q, in ICK, encoding intestinal cell kinase (ICK). Our results established that R272 is conserved across species and among ethnicities, and three-dimensional analysis of the protein structure suggests protein instability due to the R272Q mutation. We also demonstrate that the R272Q mutant fails to localize at the nucleus and has diminished kinase activity. These findings suggest that ICK plays a key role in the development of multiple organ systems.
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Affiliation(s)
- Piya Lahiry
- Robarts Research Institute, London, Ontario N6A 5K8, Canada
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Burghoorn J, Dekkers MPJ, Rademakers S, de Jong T, Willemsen R, Jansen G. Mutation of the MAP kinase DYF-5 affects docking and undocking of kinesin-2 motors and reduces their speed in the cilia of Caenorhabditis elegans. Proc Natl Acad Sci U S A 2007; 104:7157-62. [PMID: 17420466 PMCID: PMC1855366 DOI: 10.1073/pnas.0606974104] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In the cilia of the nematode Caenorhabditis elegans, anterograde intraflagellar transport (IFT) is mediated by two kinesin-2 complexes, kinesin II and OSM-3 kinesin. These complexes function together in the cilia middle segments, whereas OSM-3 alone mediates transport in the distal segments. Not much is known about the mechanisms that compartmentalize the kinesin-2 complexes or how transport by both kinesins is coordinated. Here, we identify DYF-5, a conserved MAP kinase that plays a role in these processes. Fluorescence microscopy and EM revealed that the cilia of dyf-5 loss-of-function (lf) animals are elongated and are not properly aligned into the amphid channel. Some cilia do enter the amphid channel, but the distal ends of these cilia show accumulation of proteins. Consistent with these observations, we found that six IFT proteins accumulate in the cilia of dyf-5(lf) mutants. In addition, using genetic analyses and live imaging to measure the motility of IFT proteins, we show that dyf-5 is required to restrict kinesin II to the cilia middle segments. Finally, we show that, in dyf-5(lf) mutants, OSM-3 moves at a reduced speed and is not attached to IFT particles. We propose that DYF-5 plays a role in the undocking of kinesin II from IFT particles and in the docking of OSM-3 onto IFT particles.
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Affiliation(s)
- Jan Burghoorn
- *Department of Cell Biology and Genetics and Center for Biomedical Genetics and
| | | | - Suzanne Rademakers
- *Department of Cell Biology and Genetics and Center for Biomedical Genetics and
| | | | - Rob Willemsen
- Clinical Genetics, Erasmus Medical Center, P.O. Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Gert Jansen
- *Department of Cell Biology and Genetics and Center for Biomedical Genetics and
- To whom correspondence should be addressed at:
Department of Cell Biology and Genetics, Erasmus Medical Center, P.O. Box 2040, 3000 CA, Rotterdam, The Netherlands. E-mail:
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Murata-Kamiya N, Kurashima Y, Teishikata Y, Yamahashi Y, Saito Y, Higashi H, Aburatani H, Akiyama T, Peek RM, Azuma T, Hatakeyama M. Helicobacter pylori CagA interacts with E-cadherin and deregulates the beta-catenin signal that promotes intestinal transdifferentiation in gastric epithelial cells. Oncogene 2007; 26:4617-26. [PMID: 17237808 DOI: 10.1038/sj.onc.1210251] [Citation(s) in RCA: 343] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Infection with Helicobacter pylori cagA-positive strains is associated with gastric adenocarcinoma. Intestinal metaplasia is a precancerous lesion of the stomach characterized by transdifferentiation of the gastric mucosa to an intestinal phenotype. The H. pylori cagA gene product, CagA, is delivered into gastric epithelial cells, where it undergoes tyrosine phosphorylation by Src family kinases. Tyrosine-phosphorylated CagA specifically binds to and activates SHP-2 phosphatase, thereby inducing cell-morphological transformation. We report here that CagA physically interacts with E-cadherin independently of CagA tyrosine phosphorylation. The CagA/E-cadherin interaction impairs the complex formation between E-cadherin and beta-catenin, causing cytoplasmic and nuclear accumulation of beta-catenin. CagA-deregulated beta-catenin then transactivates beta-catenin-dependent genes such as cdx1, which encodes intestinal specific CDX1 transcription factor. In addition to beta-catenin signal, CagA also transactivates p21(WAF1/Cip1), again, in a phosphorylation-independent manner. Consequently, CagA induces aberrant expression of an intestinal-differentiation marker, goblet-cell mucin MUC2, in gastric epithelial cells that have been arrested in G1 by p21(WAF1/Cip1). These results indicate that perturbation of the E-cadherin/beta-catenin complex by H. pylori CagA plays an important role in the development of intestinal metaplasia, a premalignant transdifferentiation of gastric epithelial cells from which intestinal-type gastric adenocarcinoma arises.
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Affiliation(s)
- N Murata-Kamiya
- Division of Molecular Oncology, Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan
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Fu Z, Larson KA, Chitta RK, Parker SA, Turk BE, Lawrence MW, Kaldis P, Galaktionov K, Cohn SM, Shabanowitz J, Hunt DF, Sturgill TW. Identification of yin-yang regulators and a phosphorylation consensus for male germ cell-associated kinase (MAK)-related kinase. Mol Cell Biol 2006; 26:8639-54. [PMID: 16954377 PMCID: PMC1636783 DOI: 10.1128/mcb.00816-06] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
MAK (male germ cell-associated protein kinase) and MRK/ICK (MAK-related kinase/intestinal cell kinase) are human homologs of Ime2p in Saccharomyces cerevisiae and of Mde3 and Pit1 in Schizosaccharomyces pombe and are similar to human cyclin-dependent kinase 2 (CDK2) and extracellular signal-regulated kinase 2 (ERK2). MAK and MRK require dual phosphorylation in a TDY motif catalyzed by an unidentified human threonine kinase and tyrosine autophosphorylation. Herein, we establish that human CDK-related kinase CCRK (cell cycle-related kinase) is an activating T157 kinase for MRK, whereas active CDK7/cyclin H/MAT1 complexes phosphorylate CDK2 but not MRK. Protein phosphatase 5 (PP5) interacts with MRK in a complex and dephosphorylates MRK at T157 in vitro and in situ. Thus, CCRK and PP5 are yin-yang regulators of T157 phosphorylation. To determine a substrate consensus, we screened a combinatorial peptide library with active MRK. MRK preferentially phosphorylates R-P-X-S/T-P sites, with the preference for arginine at position -3 (P-3) being more stringent than for prolines at P-2 and P+1. Using the consensus, we identified a putative phosphorylation site (RPLT(1080)S) for MRK in human Scythe, an antiapoptotic protein that interacts with MRK. MRK phosphorylates Scythe at T1080 in vitro as determined by site-directed mutagenesis and mass spectrometry, supporting the consensus and suggesting Scythe as a physiological substrate for MRK.
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Affiliation(s)
- Zheng Fu
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908-0735, USA
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Fu Z, Schroeder MJ, Shabanowitz J, Kaldis P, Togawa K, Rustgi AK, Hunt DF, Sturgill TW. Activation of a nuclear Cdc2-related kinase within a mitogen-activated protein kinase-like TDY motif by autophosphorylation and cyclin-dependent protein kinase-activating kinase. Mol Cell Biol 2005; 25:6047-64. [PMID: 15988018 PMCID: PMC1168834 DOI: 10.1128/mcb.25.14.6047-6064.2005] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Male germ cell-associated kinase (MAK) and intestinal cell kinase (ICK) are nuclear Cdc2-related kinases with nearly identical N-terminal catalytic domains and more divergent C-terminal noncatalytic domains. The catalytic domain is also related to mitogen-activated protein kinases (MAPKs) and contains a corresponding TDY motif. Nuclear localization of ICK requires subdomain XI and interactions of the conserved Arg-272, but not kinase activity or, surprisingly, any of the noncatalytic domain. Further, nuclear localization of ICK is required for its activation. ICK is activated by dual phosphorylation of the TDY motif. Phosphorylation of Tyr-159 in the TDY motif requires ICK autokinase activity but confers only basal kinase activity. Full activation requires additional phosphorylation of Thr-157 in the TDY motif. Coexpression of ICK with constitutively active MEK1 or MEK5 fails to increase ICK phosphorylation or activity, suggesting that MEKs are not involved. ICK and MAK are related to Ime2p in budding yeast, and cyclin-dependent protein kinase-activating kinase Cak1p has been placed genetically upstream of Ime2p. Recombinant Cak1p phosphorylates Thr-157 in the TDY motif of recombinant ICK and activates its activity in vitro. Coexpression of ICK with wild-type CAK1 but not kinase-inactive CAK1 in cells also increases ICK phosphorylation and activity. Our studies establish ICK as the prototype for a new group of MAPK-like kinases requiring dual phosphorylation at TDY motifs.
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Affiliation(s)
- Zheng Fu
- Department of Pharmacology and Internal Medicine, University of Virginia School, 1300 Jefferson Park Avenue, Charlottesville, Virginia 22908-0735, USA
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Bengs F, Scholz A, Kuhn D, Wiese M. LmxMPK9, a mitogen-activated protein kinase homologue affects flagellar length in Leishmania mexicana. Mol Microbiol 2005; 55:1606-15. [PMID: 15720564 DOI: 10.1111/j.1365-2958.2005.04498.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Components of mitogen-activated signal transduction pathways have been shown to be involved in flagellum biogenesis and maintenance. A mitogen-activated protein kinase homologue, designated LmxMPK9 from Leishmania mexicana, has been recently identified in a homology screen and its mRNA found to be present in all life stages. Three different splice-addition sites were used for mRNA maturation in trans-splicing in the different life stages. However, here we show that LmxMPK9 protein is exclusively found in the promastigote stage. Recombinant expression of LmxMPK9 in Escherichia coli and kinase assays revealed a temperature optimum at 27 degrees C, the optimal growth temperature for L. mexicana promastigotes, and a preference for manganese to promote substrate phosphorylation of myelin basic protein. A deletion mutant for the single-copy gene revealed significantly elongated flagella, whereas overexpression led to a subpopulation with rather short to no flagella suggesting a role for LmxMPK9 in flagellar morphogenesis.
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Affiliation(s)
- Florian Bengs
- Bernhard Nocht Institute for Tropical Medicine, Parasitology Section, Bernhard-Nocht-Strasse 74, D-20359 Hamburg, Germany
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Jensen P, Magdaleno S, Lehman KM, Rice DS, Lavallie ER, Collins-Racie L, McCoy JM, Curran T. A neurogenomics approach to gene expression analysis in the developing brain. ACTA ACUST UNITED AC 2004; 132:116-27. [PMID: 15582152 DOI: 10.1016/j.molbrainres.2004.10.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/05/2004] [Indexed: 11/20/2022]
Abstract
Secreted and transmembrane proteins provide critical functions in the signaling networks essential for neurogenesis. We used a genetic signal sequence gene trap approach to isolate 189 genes expressed during development in e16.5 whole head, e16.5 hippocampus and e14.5 cerebellum. Gene ontology programs were used to classify the genes into respective biological processes. Four major classes of biological processes known to be important during development were identified: cell communication, cell physiology processes, metabolism and morphogenesis. We used in situ hybridization to determine the temporal and spatial patterns of gene expression in the developing brain using this set of probes. The results demonstrate that gene expression patterns can highlight potential gene functions in specific brain regions. We propose that combining bioinformatics with the gene expression pattern is an effective strategy to identify genes that may play critical roles during brain development.
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Affiliation(s)
- Patricia Jensen
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, United States
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Uesaka T, Kageyama N. Cdx2 homeodomain protein regulates the expression of MOK, a member of the mitogen-activated protein kinase superfamily, in the intestinal epithelial cells. FEBS Lett 2004; 573:147-54. [PMID: 15327990 DOI: 10.1016/j.febslet.2004.07.070] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2004] [Accepted: 07/28/2004] [Indexed: 01/08/2023]
Abstract
Regulatory protein kinases are involved in various cellular processes such as proliferation, differentiation, and apoptosis. Using cDNA differential display, we identified MOK, a member of the mitogen-activated protein kinase superfamily, as one of the genes induced by a caudal-related homeobox transcription factor, Cdx2. Analysis of the 5'-flanking region of the MOK gene led to the identification of primary Cdx2 responsive element, and an electrophoretic mobility shift assay indicated that Cdx2 binds to that element. The interaction of Cdx2 with the MOK promoter region was further confirmed in vivo by chromatin immunoprecipitation assays. The expression of MOK mRNA and protein was limited to the crypt epithelial cells of the mouse intestine. We also determined the MOK activity associated with the growth arrest and induction of differentiation by sodium butyrate or Cdx2 expression in the human colon cancer cell line HT-29. Taken together, these data indicate that MOK is a direct target gene for Cdx2, and that MOK may be involved in growth arrest and differentiation in the intestinal epithelium.
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Affiliation(s)
- Toshihiro Uesaka
- Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima 734-8553, Japan.
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Shinkai Y, Satoh H, Takeda N, Fukuda M, Chiba E, Kato T, Kuramochi T, Araki Y. A testicular germ cell-associated serine-threonine kinase, MAK, is dispensable for sperm formation. Mol Cell Biol 2002; 22:3276-80. [PMID: 11971961 PMCID: PMC133803 DOI: 10.1128/mcb.22.10.3276-3280.2002] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A member of the mitogen-activated protein kinase superfamily, MAK, has been proposed to have an important role in spermatogenesis, since Mak gene expression is highly restricted to testicular germ cells. To assess the biological function of MAK, we have established MAK-deficient (Mak(-/-)) mice. Mak(-/-) mice developed normally, and no gross abnormalities were observed. Spermatogenesis of the Mak(-/-) mice was also intact, and most of the mice were fertile. However, Mak(-/-) male-derived litter sizes and their sperm motility in vitro were mildly reduced. These data show that function of MAK is not essential for spermatogenesis and male fertility.
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Affiliation(s)
- Yoichi Shinkai
- Institute for Virus Research, Kyoto University, Kyoto 606-8507, Japan.
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