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Leung KY, Weston E, De Castro SCP, Nikolopoulou E, Sudiwala S, Savery D, Eaton S, Copp AJ, Greene NDE. Association of embryonic inositol status with susceptibility to neural tube defects, metabolite profile, and maternal inositol intake. FASEB J 2024; 38:e23738. [PMID: 38855924 DOI: 10.1096/fj.202400206r] [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: 01/26/2024] [Revised: 05/14/2024] [Accepted: 05/29/2024] [Indexed: 06/11/2024]
Abstract
Maternal nutrition contributes to gene-environment interactions that influence susceptibility to common congenital anomalies such as neural tube defects (NTDs). Supplemental myo-inositol (MI) can prevent NTDs in some mouse models and shows potential for prevention of human NTDs. We investigated effects of maternal MI intake on embryonic MI status and metabolism in curly tail mice, which are genetically predisposed to NTDs that are inositol-responsive but folic acid resistant. Dietary MI deficiency caused diminished MI in maternal plasma and embryos, showing that de novo synthesis is insufficient to maintain MI levels in either adult or embryonic mice. Under normal maternal dietary conditions, curly tail embryos that developed cranial NTDs had significantly lower MI content than unaffected embryos, revealing an association between diminished MI status and failure of cranial neurulation. Expression of inositol-3-phosphate synthase 1, required for inositol biosynthesis, was less abundant in the cranial neural tube than at other axial levels. Supplemental MI or d-chiro-inositol (DCI) have previously been found to prevent NTDs in curly tail embryos. Here, we investigated the metabolic effects of MI and DCI treatments by mass spectrometry-based metabolome analysis. Among inositol-responsive metabolites, we noted a disproportionate effect on nucleotides, especially purines. We also found altered proportions of 5-methyltetrahydrolate and tetrahydrofolate in MI-treated embryos suggesting altered folate metabolism. Treatment with nucleotides or the one-carbon donor formate has also been found to prevent NTDs in curly tail embryos. Together, these findings suggest that the protective effect of inositol may be mediated through the enhanced supply of nucleotides during neural tube closure.
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Affiliation(s)
- Kit-Yi Leung
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Eleanor Weston
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Sandra C P De Castro
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Evanthia Nikolopoulou
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Sonia Sudiwala
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Dawn Savery
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Simon Eaton
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Andrew J Copp
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Nicholas D E Greene
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London, UK
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Ratchatasunthorn A, Sakagami H, Kondo H, Hipkaeo W, Chomphoo S. Temporal involvement of phosphatidylinositol 4-phosphate 5-kinase γ in differentiation of Z-bands and myofilament bundles as well as intercalated discs in mouse heart at mid-gestation. J Anat 2024; 244:1030-1039. [PMID: 38275211 PMCID: PMC11095301 DOI: 10.1111/joa.14008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Revised: 12/25/2023] [Accepted: 01/08/2024] [Indexed: 01/27/2024] Open
Abstract
Considering the occurrence of serious heart failure in a gene knockout mouse of PIP5Kγ and in congenital abnormal cases in humans in which the gene was defective as reported by others, the present study attempted to localize PIP5Kγ in the heart during prenatal stages. It was done on the basis of the supposition that phenotypes caused by gene mutation of a given molecule are owed to the functional deterioration of selective cellular sites normally expressing it at significantly higher levels in wild mice. PIP5Kγ-immunoreactivity was the highest in the heart at E10 in contrast to almost non-significant levels of the immunoreactivity in surrounding organs and tissues such as liver. The immunoreactivity gradually weakened in the heart with the prenatal age, and it was at non-significant levels at newborn and postnatal stages. Six patterns in localization of distinct immunoreactivity for PIP5Kγ were recognized in cardiomyocytes: (1) its localization on the plasma membranes and subjacent cytoplasm without association with short myofibrils and (2) its localization on them as well as short myofibrils in association with them in cardiomyocytes of early differentiation at E10; (3) its spot-like localization along long myofibrils in cardiomyocytes of advanced differentiation at E10; (4) rare occurrences of such spot-like localization along long myofibrils in cardiomyocytes of advanced differentiation at E14; (5) its localization at Z-bands of long myofibrils; and (6) its localization at intercellular junctions including the intercalated discs in cardiomyocytes of advanced differentiation at E10 and E14, especially dominant at the latter stage. No distinct localization of PIP5Kγ-immunoreactivity of any patterns was seen in the heart at E18 and P1D. The present finding suggests that sites of PIP5Kγ-appearance and probably of its high activity in cardiomyocytes are shifted from the plasma membranes through short myofibrils subjacent to the plasma membranes and long myofibrils, to Z-bands as well as to the intercalated discs during the mid-term gestation. It is further suggested that PIP5Kγ is involved in the differentiation of myofibrils as well as intercellular junctions including the intercalated discs at later stages of the mid-term gestation. Failures in its involvement in the differentiation of these structural components are thus likely to cause the mid-term gestation lethality of the mutant mice for PIP5Kγ.
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Affiliation(s)
- A Ratchatasunthorn
- Electron Microscopy Unit, Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - H Sakagami
- Department of Anatomy, School of Medicine, Kitasato University, Sagamihara, Japan
| | - H Kondo
- Electron Microscopy Unit, Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
- Department of Anatomy, Graduate School of Medicine, Tohoku University, Sendai, Japan
| | - W Hipkaeo
- Electron Microscopy Unit, Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - S Chomphoo
- Electron Microscopy Unit, Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
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Lin S, Tao C, Yan Q, Gao H, Qin L, Zhong Y, Yao Q, Zhang P, Yang J, Zou X, Xiao G. Pip5k1c expression in osteocytes regulates bone remodeling in mice. J Orthop Translat 2024; 45:36-47. [PMID: 38495744 PMCID: PMC10943313 DOI: 10.1016/j.jot.2023.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 10/22/2023] [Accepted: 10/24/2023] [Indexed: 03/19/2024] Open
Abstract
Research background The role of osteocytes in maintaining bone mass has been progressively emphasized. Pip5k1c is the most critical isoform among PIP5KIs, which can regulate cytoskeleton, biomembrane, and Ca2+ release of cells and participate in many processes, such as cell adhesion, differentiation, and apoptosis. However, its expression and function in osteocytes are still unclear. Materials and methods To determine the function of Pip5k1c in osteocytes, the expression of Pip5k1c in osteocytes was deleted by breeding the 10-kb mouse Dmp1-Cre transgenic mice with the Pip5k1cfl/fl mice. Bone histomorphometry, micro-computerized tomography analysis, immunofluorescence staining and western blotting were used to determine the effects of Pip5k1c loss on bone mass. In vitro, we explored the mechanism by siRNA knockdown of Pip5k1c in MLO-Y4 cells. Results Pip5k1c expression was decreased in osteocytes in senescent and osteoporotic tissues both in humans and mice. Loss of Pip5k1c in osteocytes led to a low bone mass in long bones and spines and impaired biomechanical properties in femur, without changes in calvariae. The loss of Pip5k1c resulted in the reduction of the protein level of type 1 collagen in tibiae and MLO-Y4 cells. Osteocyte Pip5k1c loss reduced the osteoblast and bone formation rate with high expression of sclerostin, impacting the osteoclast activities at the same time. Moreover, Pip5k1c loss in osteocytes reduced expression of focal adhesion proteins and promoted apoptosis. Conclusion Our studies demonstrate the critical role and mechanism of Pip5k1c in osteocytes in regulating bone remodeling. The translational potential of this article Osteocyte has been considered to a key role in regulating bone homeostasis. The present study has demonstrated that the significance of Pip5k1c in bone homeostasis by regulating the expression of collagen, sclerostin and focal adhesion expression, which provided a possible therapeutic target against human metabolic bone disease.
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Affiliation(s)
- Sixiong Lin
- Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, Department of Spinal Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510080, China
- Department of Biochemistry, School of Medicine, Southern University of Science and Technology, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Shenzhen, 518055, China
| | - Chu Tao
- Department of Biochemistry, School of Medicine, Southern University of Science and Technology, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Shenzhen, 518055, China
| | - Qinnan Yan
- Department of Biochemistry, School of Medicine, Southern University of Science and Technology, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Shenzhen, 518055, China
| | - Huanqing Gao
- State Key Laboratory of Genetic Engineering and School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Lei Qin
- Department of Orthopedics, Huazhong University of Science and Technology Union Shenzhen Hospital, Shenzhen, 518000, China
| | - Yiming Zhong
- Department of Biochemistry, School of Medicine, Southern University of Science and Technology, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Shenzhen, 518055, China
| | - Qing Yao
- Department of Biochemistry, School of Medicine, Southern University of Science and Technology, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Shenzhen, 518055, China
| | - Peijun Zhang
- Department of Biochemistry, School of Medicine, Southern University of Science and Technology, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Shenzhen, 518055, China
| | - Jiaming Yang
- Department of Biochemistry, School of Medicine, Southern University of Science and Technology, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Shenzhen, 518055, China
- Department of Orthopaedics & Traumatology, Stem Cells and Regenerative Medicine Laboratory, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, China
| | - Xuenong Zou
- Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, Department of Spinal Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510080, China
| | - Guozhi Xiao
- Department of Biochemistry, School of Medicine, Southern University of Science and Technology, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, Shenzhen, 518055, China
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Abstract
Phosphoinositides (PIs) are phospholipids derived from phosphatidylinositol. PIs are regulated via reversible phosphorylation, which is directed by the opposing actions of PI kinases and phosphatases. PIs constitute a minor fraction of the total cellular lipid pool but play pleiotropic roles in multiple aspects of cell biology. Genetic mutations of PI regulatory enzymes have been identified in rare congenital developmental syndromes, including ciliopathies, and in numerous human diseases, such as cancer and metabolic and neurological disorders. Accordingly, PI regulatory enzymes have been targeted in the design of potential therapeutic interventions for human diseases. Recent advances place PIs as central regulators of membrane dynamics within functionally distinct subcellular compartments. This brief review focuses on the emerging role PIs play in regulating cell signaling within the primary cilium and in directing transfer of molecules at interorganelle membrane contact sites and identifies new roles for PIs in subcellular spaces.
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Affiliation(s)
- Elizabeth Michele Davies
- Cancer Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia
| | - Christina Anne Mitchell
- Cancer Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia
| | - Harald Alfred Stenmark
- Department of Molecular Cell Biology, Institute for Cancer Research. The Norwegian Radium Hospital, Montebello, N-0379 Oslo, Norway
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Montebello, N-0379 Oslo, Norway
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5
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Morleo M, Venditti R, Theodorou E, Briere LC, Rosello M, Tirozzi A, Tammaro R, Al-Badri N, High FA, Shi J, Putti E, Ferrante L, Cetrangolo V, Torella A, Walker MA, Tenconi R, Iascone M, Mei D, Guerrini R, van der Smagt J, Kroes HY, van Gassen KLI, Bilal M, Umair M, Pingault V, Attie-Bitach T, Amiel J, Ejaz R, Rodan L, Zollino M, Agrawal PB, Del Bene F, Nigro V, Sweetser DA, Franco B. De novo missense variants in phosphatidylinositol kinase PIP5KIγ underlie a neurodevelopmental syndrome associated with altered phosphoinositide signaling. Am J Hum Genet 2023; 110:1377-1393. [PMID: 37451268 PMCID: PMC10432144 DOI: 10.1016/j.ajhg.2023.06.012] [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: 01/24/2023] [Revised: 06/22/2023] [Accepted: 06/22/2023] [Indexed: 07/18/2023] Open
Abstract
Phosphoinositides (PIs) are membrane phospholipids produced through the local activity of PI kinases and phosphatases that selectively add or remove phosphate groups from the inositol head group. PIs control membrane composition and play key roles in many cellular processes including actin dynamics, endosomal trafficking, autophagy, and nuclear functions. Mutations in phosphatidylinositol 4,5 bisphosphate [PI(4,5)P2] phosphatases cause a broad spectrum of neurodevelopmental disorders such as Lowe and Joubert syndromes and congenital muscular dystrophy with cataracts and intellectual disability, which are thus associated with increased levels of PI(4,5)P2. Here, we describe a neurodevelopmental disorder associated with an increase in the production of PI(4,5)P2 and with PI-signaling dysfunction. We identified three de novo heterozygous missense variants in PIP5K1C, which encodes an isoform of the phosphatidylinositol 4-phosphate 5-kinase (PIP5KIγ), in nine unrelated children exhibiting intellectual disability, developmental delay, acquired microcephaly, seizures, visual abnormalities, and dysmorphic features. We provide evidence that the PIP5K1C variants result in an increase of the endosomal PI(4,5)P2 pool, giving rise to ectopic recruitment of filamentous actin at early endosomes (EEs) that in turn causes dysfunction in EE trafficking. In addition, we generated an in vivo zebrafish model that recapitulates the disorder we describe with developmental defects affecting the forebrain, including the eyes, as well as craniofacial abnormalities, further demonstrating the pathogenic effect of the PIP5K1C variants.
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Affiliation(s)
- Manuela Morleo
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Naples, Italy; Department of Precision Medicine, University of Campania "Luigi Vanvitelli," Naples, Italy.
| | - Rossella Venditti
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Naples, Italy; Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II," Medical School, Naples, Italy
| | - Evangelos Theodorou
- Center for Genomic Medicine, Divisions of Pediatric Hematology/Oncology and Medical Genetics and Metabolism, Department of Pediatrics, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Lauren C Briere
- Center for Genomic Medicine, Divisions of Pediatric Hematology/Oncology and Medical Genetics and Metabolism, Department of Pediatrics, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Marion Rosello
- Sorbonne Université, INSERM U968, CNRS UMR 7210, Institut de la Vision, Paris, France
| | - Alfonsina Tirozzi
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli," Naples, Italy; Department of Epidemiology and Prevention, IRCCS NEUROMED, Pozzilli, Italy
| | - Roberta Tammaro
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Naples, Italy
| | - Nour Al-Badri
- Sorbonne Université, INSERM U968, CNRS UMR 7210, Institut de la Vision, Paris, France
| | - Frances A High
- Division of Medical Genetics & Metabolism, Massachusetts General Hospital for Children, Boston, MA 02114, USA
| | - Jiahai Shi
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Elena Putti
- Sorbonne Université, INSERM U968, CNRS UMR 7210, Institut de la Vision, Paris, France
| | - Luigi Ferrante
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Naples, Italy
| | - Viviana Cetrangolo
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Naples, Italy
| | - Annalaura Torella
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Naples, Italy; Department of Precision Medicine, University of Campania "Luigi Vanvitelli," Naples, Italy
| | - Melissa A Walker
- Department of Neurology, Division of Neurogenetics, Child Neurology, Massachusetts General Hospital, Boston, MA, USA
| | - Romano Tenconi
- Clinical Genetics Unit, Department of Women and Children's Health, University of Padova, Padova, Italy
| | - Maria Iascone
- Medical Genetics, ASST Papa Giovanni XXIII, 24127 Bergamo, Italy
| | - Davide Mei
- Meyer Children's Hospital IRCCS, Neuroscience Department, Florence, Italy
| | - Renzo Guerrini
- Meyer Children's Hospital IRCCS, Neuroscience Department, Florence, Italy
| | - Jasper van der Smagt
- Department of Genetics, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Hester Y Kroes
- Department of Genetics, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Koen L I van Gassen
- Department of Genetics, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Muhammad Bilal
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - Muhammad Umair
- Medical Genomics Research Department, King Abdullah International Medical Research Center & King Saud Bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
| | - Veronica Pingault
- Service de Médecine Génomique des Maladies Rares, et Institut Imagine, Hôpital Necker-Enfants Malades, Paris, France
| | - Tania Attie-Bitach
- Service de Médecine Génomique des Maladies Rares, et Institut Imagine, Hôpital Necker-Enfants Malades, Paris, France
| | - Jeannine Amiel
- Service de Médecine Génomique des Maladies Rares, et Institut Imagine, Hôpital Necker-Enfants Malades, Paris, France
| | - Resham Ejaz
- Division of Genetics, Department of Pediatrics, McMaster Children's Hospital, Hamilton, ON, Canada
| | - Lance Rodan
- Department of Neurology, Boston Children's Hospital, Boston, MA, USA; Division of Genetics and Genomics, Department of Pediatrics, Boston Children's Hospital, Boston, MA, USA
| | - Marcella Zollino
- Institute of Medical Genetics, A. Gemelli School of Medicine, Catholic University of the Sacred Heart, Rome, Italy
| | - Pankaj B Agrawal
- Divisions of Newborn Medicine, Boston Children's Hospital, Boston, MA, USA; Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Filippo Del Bene
- Sorbonne Université, INSERM U968, CNRS UMR 7210, Institut de la Vision, Paris, France
| | - Vincenzo Nigro
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Naples, Italy; Department of Precision Medicine, University of Campania "Luigi Vanvitelli," Naples, Italy
| | - David A Sweetser
- Center for Genomic Medicine, Divisions of Pediatric Hematology/Oncology and Medical Genetics and Metabolism, Department of Pediatrics, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
| | - Brunella Franco
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Naples, Italy; Scuola Superiore Meridionale (SSM, School of Advanced Studies), Genomics and Experimental Medicine Program, Naples, Italy; Medical Genetics, Department of Translational Medicine, University of Naples "Federico II," Via Sergio Pansini, 80131 Naples, Italy
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Bura A, Čabrijan S, Đurić I, Bruketa T, Jurak Begonja A. A Plethora of Functions Condensed into Tiny Phospholipids: The Story of PI4P and PI(4,5)P 2. Cells 2023; 12:1411. [PMID: 37408244 PMCID: PMC10216963 DOI: 10.3390/cells12101411] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 05/08/2023] [Accepted: 05/09/2023] [Indexed: 07/07/2023] Open
Abstract
Phosphoinositides (PIs) are small, phosphorylated lipids that serve many functions in the cell. They regulate endo- and exocytosis, vesicular trafficking, actin reorganization, and cell mobility, and they act as signaling molecules. The most abundant PIs in the cell are phosphatidylinositol-4-monophosphate (PI4P) and phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2]. PI4P is mostly localized at the Golgi apparatus where it regulates the anterograde trafficking from the Golgi apparatus to the plasma membrane (PM), but it also localizes at the PM. On the other hand, the main localization site of PI(4,5)P2 is the PM where it regulates the formation of endocytic vesicles. The levels of PIs are regulated by many kinases and phosphatases. Four main kinases phosphorylate the precursor molecule phosphatidylinositol into PI4P, divided into two classes (PI4KIIα, PI4KIIβ, PI4KIIIα, and PI4KIIIβ), and three main kinases phosphorylate PI4P to form PI(4,5)P2 (PI4P5KIα, PI4P5KIβ, and PI4P5KIγ). In this review, we discuss the localization and function of the kinases that produce PI4P and PI(4,5)P2, as well as the localization and function of their product molecules with an overview of tools for the detection of these PIs.
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Affiliation(s)
| | | | | | | | - Antonija Jurak Begonja
- Laboratory of Hematopoiesis, Department of Biotechnology, University of Rijeka, R. Matejcic 2, 51000 Rijeka, Croatia
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7
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Llorente A, Arora GK, Grenier SF, Emerling BM. PIP kinases: A versatile family that demands further therapeutic attention. Adv Biol Regul 2023; 87:100939. [PMID: 36517396 PMCID: PMC9992244 DOI: 10.1016/j.jbior.2022.100939] [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: 11/21/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022]
Abstract
Phosphoinositides are membrane-localized phospholipids that regulate a plethora of essential cellular processes. These lipid signaling molecules are critical for cell homeostasis and therefore their levels are strictly regulated by the coordinated action of several families of lipid kinases and phosphatases. In this review, we provide a focused perspective on the phosphatidylinositol phosphate kinase (PIPK) family and the three subfamilies that compose it: Type I PIPKs or phosphatidylinositol-4-phosphate 5-kinases (PI4P5Ks), Type II PIPKs or phosphatidylinositol-5-phosphate 4-kinases (PI5P4Ks), and Type III PIPKs or phosphatidylinositol-3-phosphate 5-kinases (PIKfyve). Each subfamily is responsible for catalyzing a hydroxyl phosphorylation on specific phosphoinositide species to generate a double phosphorylated lipid, therefore regulating the levels of both substrate and product. Here, we summarize our current knowledge about the functions and regulation of each PIPK subfamily. Further, we highlight the roles of these kinases in various in vivo genetic models and give an overview of their involvement in multiple pathological conditions. The phosphoinositide field has been long focused on targeting PI3K signaling, but growing evidence suggests that it is time to draw attention to the other phosphoinositide kinases. The discovery of the involvement of PIPKs in the pathogenesis of multiple diseases has prompted substantial efforts to turn these enzymes into pharmacological targets. An increasingly refined knowledge of the biology of PIPKs in a variety of in vitro and in vivo models will facilitate the development of effective approaches for therapeutic intervention with the potential to translate into meaningful clinical benefits for patients suffering from cancer, immunological and infectious diseases, and neurodegenerative disorders.
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Affiliation(s)
- Alicia Llorente
- Cell and Molecular Biology of Cancer Program, Sanford Burnham Prebys, La Jolla, CA, 92037, USA
| | - Gurpreet K Arora
- Cell and Molecular Biology of Cancer Program, Sanford Burnham Prebys, La Jolla, CA, 92037, USA
| | - Shea F Grenier
- Cell and Molecular Biology of Cancer Program, Sanford Burnham Prebys, La Jolla, CA, 92037, USA
| | - Brooke M Emerling
- Cell and Molecular Biology of Cancer Program, Sanford Burnham Prebys, La Jolla, CA, 92037, USA.
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8
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Ameen M, Sundaram L, Shen M, Banerjee A, Kundu S, Nair S, Shcherbina A, Gu M, Wilson KD, Varadarajan A, Vadgama N, Balsubramani A, Wu JC, Engreitz JM, Farh K, Karakikes I, Wang KC, Quertermous T, Greenleaf WJ, Kundaje A. Integrative single-cell analysis of cardiogenesis identifies developmental trajectories and non-coding mutations in congenital heart disease. Cell 2022; 185:4937-4953.e23. [PMID: 36563664 PMCID: PMC10122433 DOI: 10.1016/j.cell.2022.11.028] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 09/13/2022] [Accepted: 11/23/2022] [Indexed: 12/24/2022]
Abstract
To define the multi-cellular epigenomic and transcriptional landscape of cardiac cellular development, we generated single-cell chromatin accessibility maps of human fetal heart tissues. We identified eight major differentiation trajectories involving primary cardiac cell types, each associated with dynamic transcription factor (TF) activity signatures. We contrasted regulatory landscapes of iPSC-derived cardiac cell types and their in vivo counterparts, which enabled optimization of in vitro differentiation of epicardial cells. Further, we interpreted sequence based deep learning models of cell-type-resolved chromatin accessibility profiles to decipher underlying TF motif lexicons. De novo mutations predicted to affect chromatin accessibility in arterial endothelium were enriched in congenital heart disease (CHD) cases vs. controls. In vitro studies in iPSCs validated the functional impact of identified variation on the predicted developmental cell types. This work thus defines the cell-type-resolved cis-regulatory sequence determinants of heart development and identifies disruption of cell type-specific regulatory elements in CHD.
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Affiliation(s)
- Mohamed Ameen
- Department of Cancer Biology, Stanford University, Stanford, CA, USA; Illumina Artificial Intelligence Laboratory, Illumina Inc, Foster City, CA, USA
| | - Laksshman Sundaram
- Department of Computer Science, Stanford University, Stanford, CA, USA; Illumina Artificial Intelligence Laboratory, Illumina Inc, Foster City, CA, USA
| | - Mengcheng Shen
- Cardiovascular Institute, Stanford University, Stanford, CA, USA
| | - Abhimanyu Banerjee
- Illumina Artificial Intelligence Laboratory, Illumina Inc, Foster City, CA, USA; Department of Physics, Stanford University, Stanford, CA, USA
| | - Soumya Kundu
- Department of Computer Science, Stanford University, Stanford, CA, USA
| | - Surag Nair
- Department of Computer Science, Stanford University, Stanford, CA, USA
| | - Anna Shcherbina
- Department of Biomedical Informatics, Stanford University, Stanford, CA, USA
| | - Mingxia Gu
- Center for Stem Cell and Organoid Medicine, CuSTOM, Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | | | - Avyay Varadarajan
- Department of Computer Science, California Institute of Technology, Pasadena, CA, USA
| | - Nirmal Vadgama
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | | | - Joseph C Wu
- Cardiovascular Institute, Stanford University, Stanford, CA, USA
| | | | - Kyle Farh
- Illumina Artificial Intelligence Laboratory, Illumina Inc, Foster City, CA, USA
| | - Ioannis Karakikes
- Cardiovascular Institute, Stanford University, Stanford, CA, USA; Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA.
| | - Kevin C Wang
- Department of Cancer Biology, Stanford University, Stanford, CA, USA; Department of Dermatology, Stanford University School of Medicine, Stanford, CA, USA; Veterans Affairs Palo Alto Healthcare System, Palo Alto, CA, USA.
| | - Thomas Quertermous
- Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA.
| | - William J Greenleaf
- Department of Genetics, Stanford University, Stanford, CA, USA; Department of Applied Physics, Stanford University, Stanford, CA, USA.
| | - Anshul Kundaje
- Department of Computer Science, Stanford University, Stanford, CA, USA; Department of Genetics, Stanford University, Stanford, CA, USA.
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9
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Chen C, Hu J, Ling K. The Role of Primary Cilia-Associated Phosphoinositide Signaling in Development. J Dev Biol 2022; 10:51. [PMID: 36547473 PMCID: PMC9785882 DOI: 10.3390/jdb10040051] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 11/22/2022] [Accepted: 11/24/2022] [Indexed: 12/07/2022] Open
Abstract
Primary cilia are microtube-based organelles that extend from the cell surface and function as biochemical and mechanical extracellular signal sensors. Primary cilia coordinate a series of signaling pathways during development. Cilia dysfunction leads to a pleiotropic group of developmental disorders, termed ciliopathy. Phosphoinositides (PIs), a group of signaling phospholipids, play a crucial role in development and tissue homeostasis by regulating membrane trafficking, cytoskeleton reorganization, and organelle identity. Accumulating evidence implicates the involvement of PI species in ciliary defects and ciliopathies. The abundance and localization of PIs in the cell are tightly regulated by the opposing actions of kinases and phosphatases, some of which are recently discovered in the context of primary cilia. Here, we review several cilium-associated PI kinases and phosphatases, including their localization along cilia, function in regulating the ciliary biology under normal conditions, as well as the connection of their disease-associated mutations with ciliopathies.
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Affiliation(s)
- Chuan Chen
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA
| | - Jinghua Hu
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA
| | - Kun Ling
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
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10
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Weston E, Pangilinan F, Eaton S, Orford M, Leung KY, Copp AJ, Mills JL, Molloy AM, Brody LC, Greene NDE. Investigating Genetic Determinants of Plasma Inositol Status in Adult Humans. J Nutr 2022; 152:2333-2342. [PMID: 36774100 PMCID: PMC9644178 DOI: 10.1093/jn/nxac204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 08/02/2022] [Accepted: 08/26/2022] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Myo-inositol (MI) is incorporated into numerous biomolecules, including phosphoinositides and inositol phosphates. Disturbance of inositol availability or metabolism is associated with various disorders, including neurological conditions and cancers, whereas supplemental MI has therapeutic potential in conditions such as depression, polycystic ovary syndrome, and congenital anomalies. Inositol status can be influenced by diet, synthesis, transport, utilization, and catabolism. OBJECTIVES We aimed to investigate potential genetic regulation of circulating MI status and to evaluate correlation of MI concentration with other metabolites. METHODS GC-MS was used to determine plasma MI concentration of >2000 healthy, young adults (aged 18-28 y) from the Trinity Student Study. Genotyping data were used to test association of plasma MI with single nucleotide polymorphisms (SNPs) in candidate genes, encoding inositol transporters and synthesizing enzymes, and test for genome-wide association. We evaluated potential correlation of plasma MI with d-chiro-inositol (DCI), glucose, and other metabolites by Spearman rank correlation. RESULTS Mean plasma MI showed a small but significant difference between males and females (28.5 and 26.9 μM, respectively). Candidate gene analysis revealed several nominally significant associations with plasma MI, most notably for SLC5A11 (solute carrier family 5 member 11), encoding a sodium-coupled inositol transporter, also known as SMIT2 (sodium-dependent myo-inositol transporter 2). However, these did not survive correction for multiple testing. Subsequent testing for genome-wide association with plasma MI did not identify associations of genome-wide significance (P < 5 × 10-8). However, 8 SNPs exceeded the threshold for suggestive significant association with plasma MI concentration (P < 1 × 10-5), 3 of which were located within or close to genes: MTDH (metadherin), LAPTM4B (lysosomal protein transmembrane 4 β), and ZP2 (zona pellucida 2). We found significant positive correlation of plasma MI concentration with concentration of dci and several other biochemicals including glucose, methionine, betaine, sarcosine, and tryptophan. CONCLUSIONS Our findings suggest potential for modulation of plasma MI in young adults by variation in SLC5A11, which is worthy of further investigation.
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Affiliation(s)
- Eleanor Weston
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - Faith Pangilinan
- Genetics and Environment Interaction Section, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Simon Eaton
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - Michael Orford
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - Kit-Yi Leung
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - Andrew J Copp
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - James L Mills
- Epidemiology Branch, Division of Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Anne M Molloy
- Department of Clinical Medicine, School of Medicine, Trinity College, Dublin, Ireland
| | - Lawrence C Brody
- Genetics and Environment Interaction Section, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
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11
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Huang G, Yang C, Guo S, Huang M, Deng L, Huang Y, Chen P, Chen F, Huang X. Adipocyte-specific deletion of PIP5K1c reduces diet-induced obesity and insulin resistance by increasing energy expenditure. Lipids Health Dis 2022; 21:6. [PMID: 34996482 PMCID: PMC8742433 DOI: 10.1186/s12944-021-01616-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 12/17/2021] [Indexed: 12/23/2022] Open
Abstract
Background Phosphatidylinositol 4-phosphate 5-kinase type I c (PIP5K1c) catalyses the synthesis of phospholipid phosphatidylinositol 4,5-bisphosphate (PIP2) by phosphorylating phosphatidylinositol 4 phosphate, which plays multiple roles in regulating focal adhesion formation, invasion, and cell migration signal transduction cascades. Here, a new physiological mechanism of PIP5K1c in adipocytes and systemic metabolism is reported. Methods Adipose-specific conditional knockout mice were generated to delete the PIP5K1c gene in adipocytes. In addition, in vitro research investigated the effect of PIP5K1c deletion on adipogenesis. Results Deletion of PIP5K1c in adipocytes significantly alleviated high fat diet (HFD)-induced obesity, hyperlipidaemia, hepatic steatosis, and insulin resistance. PIP5K1c deficiency in adipocytes also decreased adipocyte volume in HFD-induced obese mice, whereas no significant differences were observed in body weight and adipose tissue weight under normal chow diet conditions. PIP5K1c knockout in adipocytes significantly enhanced energy expenditure, which protected mice from HFD-induced weight gain. In addition, adipogenesis was markedly impaired in mouse stromal vascular fraction (SVF) from PIP5K1c-deleted mice. Conclusion Under HFD conditions, PIP5K1c regulates adipogenesis and adipose tissue homeostasis. Together, these data indicate that PIP5K1c could be a novel potential target for regulating fat accumulation, which could provide novel insight into the treatment of obesity. Supplementary Information The online version contains supplementary material available at 10.1186/s12944-021-01616-4.
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Affiliation(s)
- Guan Huang
- Department of Pathology, Shenzhen Clinical Medical College, Guangzhou University of Chinese Medicine, Longgang District Central Hospital of Shenzhen, Shenzhen, 518116, Guangdong, China
| | - Cuishan Yang
- Department of Nursing, Shenzhen Clinical Medical College, Guangzhou University of Chinese Medicine, Longgang District Central Hospital of Shenzhen, Shenzhen, 518116, Guangdong, China
| | - Sheng Guo
- Department of Medical Administration, Shenzhen Clinical Medical College, Guangzhou University of Chinese Medicine, Longgang District Central Hospital of Shenzhen, Shenzhen, 518116, Guangdong, China
| | - Miaoling Huang
- Department of Metabolism and Endocrinology, Shenzhen Clinical Medical College, Guangzhou University of Chinese Medicine, Longgang District Central Hospital of Shenzhen, Shenzhen, 518116, Guangdong, China
| | - Liping Deng
- Department of Metabolism and Endocrinology, Shenzhen Clinical Medical College, Guangzhou University of Chinese Medicine, Longgang District Central Hospital of Shenzhen, Shenzhen, 518116, Guangdong, China
| | - Ying Huang
- Department of Metabolism and Endocrinology, Shenzhen Clinical Medical College, Guangzhou University of Chinese Medicine, Longgang District Central Hospital of Shenzhen, Shenzhen, 518116, Guangdong, China
| | - Puxin Chen
- Department of Metabolism and Endocrinology, Shenzhen Clinical Medical College, Guangzhou University of Chinese Medicine, Longgang District Central Hospital of Shenzhen, Shenzhen, 518116, Guangdong, China
| | - Feng Chen
- Department of Plastic Surgy, Shenzhen Clinical Medical College, Guangzhou University of Chinese Medicine; Longgang District Central Hospital of Shenzhen, Shenzhen, 518116, Guangdong, China.
| | - Xiaohong Huang
- Department of Nursing, Shenzhen Clinical Medical College, Guangzhou University of Chinese Medicine, Longgang District Central Hospital of Shenzhen, Shenzhen, 518116, Guangdong, China.
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12
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Loss of phosphatidylinositol-4-phosphate 5-kinase type-1 gamma (Pip5k1c) in mesenchymal stem cells leads to osteopenia by impairing bone remodeling. J Biol Chem 2022; 298:101639. [PMID: 35090892 PMCID: PMC8867119 DOI: 10.1016/j.jbc.2022.101639] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 01/19/2022] [Accepted: 01/20/2022] [Indexed: 01/10/2023] Open
Abstract
Phosphatidylinositol-4-phosphate 5-kinase type-1 gamma (Pip5k1c) is a lipid kinase that plays a pivotal role in the regulation of receptor-mediated calcium signaling in multiple tissues; however, its role in the skeleton is not clear. Here, we show that while deleting Pip5k1c expression in the mesenchymal stem cells using Prx1-Cre transgenic mice does not impair the intramembranous and endochondral ossification during skeletal development, it does cause osteopenia in adult mice, but not rapidly growing young mice. We found Pip5k1c loss dramatically decreases osteoblast formation and osteoid and mineral deposition, leading to reduced bone formation. Furthermore, Pip5k1c loss inhibits osteoblastic, but promotes adipogenic, differentiation of bone marrow stromal cells. Pip5k1c deficiency also impairs cytoplasmic calcium influx and inactivates the calcium/calmodulin-dependent protein kinase, which regulates levels of transcription factor Runx2 by modulating its stability and subsequent osteoblast and bone formation. In addition, Pip5k1c loss reduces levels of the receptor activator of nuclear factor-κB ligand, but not that of osteoprotegerin, its decoy receptor, in osteoblasts in bone and in sera. Finally, we found Pip5k1c loss impairs the ability of bone marrow stromal cells to support osteoclast formation of bone marrow monocytes and reduces the osteoclast precursor population in bone marrow, resulting in reduced osteoclast formation and bone resorption. We conclude Pip5k1c deficiency causes a low-turnover osteopenia in mice, with impairment of bone formation being greater than that of bone resorption. Collectively, we uncover a novel function and mechanism of Pip5k1c in the control of bone mass and identify a potential therapeutic target for osteoporosis.
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13
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Chen C, Xu Q, Zhang Y, Davies BA, Huang Y, Katzmann DJ, Harris PC, Hu J, Ling K. Ciliopathy protein HYLS1 coordinates the biogenesis and signaling of primary cilia by activating the ciliary lipid kinase PIPKIγ. SCIENCE ADVANCES 2021; 7:7/26/eabe3401. [PMID: 34162535 PMCID: PMC8221637 DOI: 10.1126/sciadv.abe3401] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 05/10/2021] [Indexed: 05/04/2023]
Abstract
Mutation of ciliopathy protein HYLS1 causes the perinatal lethal hydrolethalus syndrome (HLS), yet the underlying molecular etiology and pathogenesis remain elusive. Here, we reveal unexpected mechanistic insights into the role of mammalian HYLS1 in regulating primary cilia. HYLS1 is recruited to the ciliary base via a direct interaction with the type Iγ phosphatidylinositol 4-phosphate [PI(4)P] 5-kinase (PIPKIγ). HYLS1 activates PIPKIγ by interrupting the autoinhibitory dimerization of PIPKIγ, which thereby expedites depletion of centrosomal PI(4)P to allow axoneme nucleation. HYLS1 deficiency interrupts the assembly of ciliary NPHP module and agonist-induced ciliary exit of β-arrestin, which, in turn, disturbs the removal of ciliary Gpr161 and activation of hedgehog (Hh) signaling. Consistent with this model of pathogenesis, the HLS mutant HYLS1D211G supports ciliogenesis but not activation of Hh signaling. These results implicate mammalian HYLS1 as a multitasking protein that facilitates ciliogenesis and ciliary signaling by coordinating with the ciliary lipid kinase PIPKIγ.
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Affiliation(s)
- Chuan Chen
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA
| | - Qingwen Xu
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
| | - Yuxia Zhang
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA
| | - Brian A Davies
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
| | - Yan Huang
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA
| | - David J Katzmann
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
| | - Peter C Harris
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA
| | - Jinghua Hu
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA
| | - Kun Ling
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA.
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14
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Yue H, Li S, Qin J, Gao T, Lyu J, Liu Y, Wang X, Guan Z, Zhu Z, Niu B, Zhong R, Guo J, Wang J. Down-Regulation of Inpp5e Associated With Abnormal Ciliogenesis During Embryonic Neurodevelopment Under Inositol Deficiency. Front Neurol 2021; 12:579998. [PMID: 34093381 PMCID: PMC8170399 DOI: 10.3389/fneur.2021.579998] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Accepted: 04/20/2021] [Indexed: 12/11/2022] Open
Abstract
The inositol polyphosphate-5-phosphatase E (Inpp5e) gene is located on chromosome 9q34.3. The enzyme it encodes mainly hydrolyzes the 5-phosphate groups of phosphatidylinositol (3,4,5)-trisphosphate (PtdIns (3,4,5) P3) and phosphatidylinositol (4,5)-bisphosphate (PtdIns (4,5)P2), which are closely related to ciliogenesis and embryonic neurodevelopment, through mechanisms that are largely unknown. Here we studied the role of Inpp5e gene in ciliogenesis during embryonic neurodevelopment using inositol-deficiency neural tube defects (NTDs) mouse and cell models. Confocal microscopy and scanning electron microscope were used to examine the number and the length of primary cilia. The dynamic changes of Inpp5e expression in embryonic murine brain tissues were observed during Embryonic Day 10.5-13.5 (E 10.5-13.5). Immunohistochemistry, western blot, polymerase chain reaction (PCR) arrays were applied to detect the expression of Inpp5e and cilia-related genes of the embryonic brain tissues in inositol deficiency NTDs mouse. Real-time quantitative PCR (RT-qPCR) was used to validate the candidate genes in cell models. The levels of inositol and PtdIns(3,4) P2 were measured using gas chromatography-mass spectrometry (GC-MS) and enzyme linked immunosorbent assay (ELISA), respectively. Our results showed that the expression levels of Inpp5e gradually decreased in the forebrain tissues of the control embryos, but no stable trend was observed in the inositol deficiency NTDs embryos. Inpp5e expression in inositol deficiency NTDs embryos was significantly decreased compared with the control tissues. The expression levels of Inpp5e gene and the PtdIns (3,4) P2 levels were also significantly decreased in the inositol deficient cell model. A reduced number and length of primary cilia were observed in NIH3T3 cells when inositol deficient. Three important cilia-related genes (Ift80, Mkks, Smo) were down-regulated significantly in the inositol-deficient NTDs mouse and cell models, and Smo was highly involved in NTDs. In summary, these findings suggested that down-regulation of Inpp5e might be associated with abnormal ciliogenesis during embryonic neurodevelopment, under conditions of inositol deficiency.
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Affiliation(s)
- Huixuan Yue
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China
- Graduate School of Peking Union Medical College, Beijing, China
| | - Shen Li
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China
- Graduate School of Peking Union Medical College, Beijing, China
| | - Jiaxing Qin
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China
| | - Tingting Gao
- Beijing Key Laboratory of Environment and Viral Oncology, College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China
| | - Jianjun Lyu
- Department of Pathology, InnoStar Bio-Tech Nantong Co., Ltd., Nantong, China
| | - Yu Liu
- Beijing Key Laboratory of Environment and Viral Oncology, College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China
| | - Xiuwei Wang
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China
| | - Zhen Guan
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China
| | - Zhiqiang Zhu
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China
| | - Bo Niu
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China
| | - Rugang Zhong
- Beijing Key Laboratory of Environment and Viral Oncology, College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China
| | - Jin Guo
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China
| | - Jianhua Wang
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China
- Graduate School of Peking Union Medical College, Beijing, China
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15
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Zhao X, Cui P, Hu G, Wang C, Jiang L, Zhao J, Xu J, Zhang X. PIP5k1β controls bone homeostasis through modulating both osteoclast and osteoblast differentiation. J Mol Cell Biol 2021; 12:55-70. [PMID: 30986855 PMCID: PMC7052985 DOI: 10.1093/jmcb/mjz028] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 11/16/2018] [Accepted: 12/21/2018] [Indexed: 02/07/2023] Open
Abstract
PIP5k1β is crucial to the generation of phosphotidylinosotol (4, 5)P2. PIP5k1β participates in numerous cellular activities, such as B cell and platelet activation, cell phagocytosis and endocytosis, cell apoptosis, and cytoskeletal organization. In the present work, we aimed to examine the function of PIP5k1β in osteoclastogenesis and osteogenesis to provide promising strategies for osteoporosis prevention and treatment. We discovered that PIP5k1β deletion in mice resulted in obvious bone loss and that PIP5k1β was highly expressed during both osteoclast and osteoblast differentiation. Deletion of the gene was found to enhance the proliferation and migration of bone marrow-derived macrophage-like cells to promote osteoclast differentiation. PIP5k1β-/- osteoclasts exhibited normal cytoskeleton architecture but stronger resorption activity. PIP5k1β deficiency also promoted activation of mitogen-activated kinase and Akt signaling, enhanced TRAF6 and c-Fos expression, facilitated the expression and nuclear translocation of NFATC1, and upregulated Grb2 expression, thereby accelerating osteoclast differentiation and function. Finally, PIP5k1β enhanced osteoblast differentiation by upregulating master gene expression through triggering smad1/5/8 signaling. Therefore, PIP5k1β modulates bone homeostasis and remodeling.
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Affiliation(s)
- Xiaoying Zhao
- Department of Orthopedic Surgery, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200092, China.,The Key Laboratory of Stem Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200025, China
| | - Penglei Cui
- Department of Orthopedic Surgery, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200092, China
| | - Guoli Hu
- Department of Orthopedic Surgery, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200092, China.,The Key Laboratory of Stem Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200025, China
| | - Chuandong Wang
- Department of Orthopedic Surgery, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200092, China
| | - Lei Jiang
- Key Laboratory of Tibetan Medicine Research, Northwest Plateau Institute of Biology, Chinese Academy of Sciences, Xining 810001, China
| | - Jingyu Zhao
- Department of Orthopedic Surgery, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200092, China.,The Key Laboratory of Stem Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200025, China
| | - Jiake Xu
- School of Pathology and Laboratory Medicine, University of Western Australia, Perth, Western Australia, 6009, Australia
| | - Xiaoling Zhang
- Department of Orthopedic Surgery, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200092, China.,The Key Laboratory of Stem Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200025, China
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16
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Conduit SE, Vanhaesebroeck B. Phosphoinositide lipids in primary cilia biology. Biochem J 2020; 477:3541-3565. [PMID: 32970140 PMCID: PMC7518857 DOI: 10.1042/bcj20200277] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 07/30/2020] [Accepted: 08/27/2020] [Indexed: 12/11/2022]
Abstract
Primary cilia are solitary signalling organelles projecting from the surface of most cell types. Although the ciliary membrane is continuous with the plasma membrane it exhibits a unique phospholipid composition, a feature essential for normal cilia formation and function. Recent studies have illustrated that distinct phosphoinositide lipid species localise to specific cilia subdomains, and have begun to build a 'phosphoinositide map' of the cilium. The abundance and localisation of phosphoinositides are tightly regulated by the opposing actions of lipid kinases and lipid phosphatases that have also been recently discovered at cilia. The critical role of phosphoinositides in cilia biology is highlighted by the devastating consequences of genetic defects in cilia-associated phosphoinositide regulatory enzymes leading to ciliopathy phenotypes in humans and experimental mouse and zebrafish models. Here we provide a general introduction to primary cilia and the roles phosphoinositides play in cilia biology. In addition to increasing our understanding of fundamental cilia biology, this rapidly expanding field may inform novel approaches to treat ciliopathy syndromes caused by deregulated phosphoinositide metabolism.
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Affiliation(s)
- Sarah E. Conduit
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6BT, U.K
| | - Bart Vanhaesebroeck
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6BT, U.K
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17
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Abstract
During embryonic development, the central nervous system forms as the neural plate and then rolls into a tube in a complex morphogenetic process known as neurulation. Neural tube defects (NTDs) occur when neurulation fails and are among the most common structural birth defects in humans. The frequency of NTDs varies greatly anywhere from 0.5 to 10 in 1000 live births, depending on the genetic background of the population, as well as a variety of environmental factors. The prognosis varies depending on the size and placement of the lesion and ranges from death to severe or moderate disability, and some NTDs are asymptomatic. This chapter reviews how mouse models have contributed to the elucidation of the genetic, molecular, and cellular basis of neural tube closure, as well as to our understanding of the causes and prevention of this devastating birth defect.
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Affiliation(s)
- Irene E Zohn
- Center for Genetic Medicine, Children's Research Institute, Children's National Medical Center, Washington, DC, USA.
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18
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Du H, Zou L, Ren R, Li N, Li J, Wang Y, Sun J, Yang J, Xiong W, Xu Z. Lack of PDZD7 long isoform disrupts ankle-link complex and causes hearing loss in mice. FASEB J 2019; 34:1136-1149. [PMID: 31914662 DOI: 10.1096/fj.201901657rr] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 09/28/2019] [Accepted: 11/14/2019] [Indexed: 12/12/2022]
Abstract
Usher syndrome (USH) is the most frequent form of combined hereditary deafness-blindness, characterized by hearing loss and retinitis pigmentosa, with or without vestibular dysfunction. PDZD7 is a PDZ domain-containing scaffold protein that was suggested to be a USH modifier and a contributor to digenic USH. In the inner ear hair cells, PDZD7 localizes at the ankle region of the stereocilia and constitutes the so-called ankle-link complex together with three other USH proteins Usherin, WHRN, and ADGRV1. PDZD7 gene is subjected to alternative splicing, which gives rise to two types of PDZD7 isoforms, namely the long and short isoforms. At present, little is known which specific isoform is involved in ankle-link formation and stereocilia development. In this work, we showed that PDZD7 long isoform, but not short isoforms, localizes at the ankle region of the stereocilia. Moreover, we established Pdzd7 mutant mice by introducing deletions into exon 14 of the Pdzd7 gene, which causes potential premature translational stop in the long isoform but leaves short isoforms unaffected. We found that lack of PDZD7 long isoform affects the localization of other ankle-link complex components in the stereocilia. Consequently, Pdzd7 mutant mice showed stereocilia development deficits and hearing loss as well as reduced mechanotransduction (MET) currents, suggesting that PDZD7 long isoform is indispensable for hair cells. Furthermore, by performing yeast two-hybrid screening, we identified a PDZD7 long isoform-specific binding partner PIP5K1C, which has been shown to play important roles in hearing and might participate in the function and/or transportation of PDZD7.
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Affiliation(s)
- Haibo Du
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Linzhi Zou
- School of Life Sciences, IDG/McGovern Institute for Brain Research at Tsinghua, Tsinghua University, Beijing, China
| | - Rui Ren
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Nana Li
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Jie Li
- School of Life Sciences, IDG/McGovern Institute for Brain Research at Tsinghua, Tsinghua University, Beijing, China
| | - Yanfei Wang
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Jinpeng Sun
- Key Laboratory Experimental Teratology of the Ministry of Education, Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, China
| | - Jun Yang
- Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah, Salt Lake City, Utah
| | - Wei Xiong
- School of Life Sciences, IDG/McGovern Institute for Brain Research at Tsinghua, Tsinghua University, Beijing, China
| | - Zhigang Xu
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China.,Shandong Provincial Collaborative Innovation Center of Cell Biology, Shandong Normal University, Jinan, China
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Volpatti JR, Al-Maawali A, Smith L, Al-Hashim A, Brill JA, Dowling JJ. The expanding spectrum of neurological disorders of phosphoinositide metabolism. Dis Model Mech 2019; 12:12/8/dmm038174. [PMID: 31413155 PMCID: PMC6737944 DOI: 10.1242/dmm.038174] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Phosphoinositides (PIPs) are a ubiquitous group of seven low-abundance phospholipids that play a crucial role in defining localized membrane properties and that regulate myriad cellular processes, including cytoskeletal remodeling, cell signaling cascades, ion channel activity and membrane traffic. PIP homeostasis is tightly regulated by numerous inositol kinases and phosphatases, which phosphorylate and dephosphorylate distinct PIP species. The importance of these phospholipids, and of the enzymes that regulate them, is increasingly being recognized, with the identification of human neurological disorders that are caused by mutations in PIP-modulating enzymes. Genetic disorders of PIP metabolism include forms of epilepsy, neurodegenerative disease, brain malformation syndromes, peripheral neuropathy and congenital myopathy. In this Review, we provide an overview of PIP function and regulation, delineate the disorders associated with mutations in genes that modulate or utilize PIPs, and discuss what is understood about gene function and disease pathogenesis as established through animal models of these diseases. Summary: This Review highlights the intersection between phosphoinositides and the enzymes that regulate their metabolism, which together are crucial regulators of myriad cellular processes and neurological disorders.
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Affiliation(s)
- Jonathan R Volpatti
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Almundher Al-Maawali
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Genetics, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat 123, Oman
| | - Lindsay Smith
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Aqeela Al-Hashim
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Neuroscience, King Fahad Medical City, Riyadh 11525, Saudi Arabia
| | - Julie A Brill
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada.,Program in Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - James J Dowling
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada .,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
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20
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Khadka B, Gupta RS. Novel Molecular Signatures in the PIP4K/PIP5K Family of Proteins Specific for Different Isozymes and Subfamilies Provide Important Insights into the Evolutionary Divergence of this Protein Family. Genes (Basel) 2019; 10:genes10040312. [PMID: 31010098 PMCID: PMC6523245 DOI: 10.3390/genes10040312] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 04/10/2019] [Accepted: 04/15/2019] [Indexed: 02/07/2023] Open
Abstract
Members of the PIP4K/PIP5K family of proteins, which generate the highly important secondary messenger phosphatidylinositol-4,5-bisphosphate, play central roles in regulating diverse signaling pathways. In eukaryotic organisms, multiple isozymes and subfamilies of PIP4K/PIP5K proteins are found and it is of much interest to understand their evolution and species distribution and what unique molecular and biochemical characteristics distinguish specific isozymes and subfamilies of proteins. We report here the species distribution of different PIP4K/PIP5K family of proteins in eukaryotic organisms and phylogenetic analysis based on their protein sequences. Our results indicate that the distinct homologs of both PIP4K and PIP5K are found in different organisms belonging to the Holozoa clade of eukaryotes, which comprises of various metazoan phyla as well as their close unicellular relatives Choanoflagellates and Filasterea. In contrast, the deeper-branching eukaryotic lineages, as well as plants and fungi, contain only a single homolog of the PIP4K/PIP5K proteins. In parallel, our comparative analyses of PIP4K/PIP5K protein sequences have identified six highly-specific molecular markers consisting of conserved signature indels (CSIs) that are uniquely shared by either the PIP4K or PIP5K proteins, or both, or specific subfamilies of these proteins. Of these molecular markers, 2 CSIs are distinctive characteristics of all PIP4K homologs, 1 CSI distinguishes the PIP4K and PIP5K homologs from the Holozoa clade of species from the ancestral form of PIP4K/PIP5K found in deeper-branching eukaryotic lineages. The remaining three CSIs are specific for the PIP5Kα, PIP5Kβ, and PIP4Kγ subfamilies of proteins from vertebrate species. These molecular markers provide important means for distinguishing different PIP4K/PIP5K isozymes as well as some of their subfamilies. In addition, the distribution patterns of these markers in different isozymes provide important insights into the evolutionary divergence of PIP4K/PIP5K proteins. Our results support the view that the Holozoa clade of eukaryotic organisms shared a common ancestor exclusive of the other eukaryotic lineages and that the initial gene duplication event leading to the divergence of distinct types of PIP4K and PIP5K homologs occurred in a common ancestor of this clade. Based on the results gleaned from different studies presented here, a model for the evolutionary divergence of the PIP4K/PIP5K family of proteins is presented.
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Affiliation(s)
- Bijendra Khadka
- Department of Biochemistry and Biomedical Sciences McMaster University, Hamilton, ON L8N 3Z5, Canada.
| | - Radhey S Gupta
- Department of Biochemistry and Biomedical Sciences McMaster University, Hamilton, ON L8N 3Z5, Canada.
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21
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Loo L, Zylka M. Conditional deletion of Pip5k1c in sensory ganglia and effects on nociception and inflammatory sensitization. Mol Pain 2018; 13:1744806917737907. [PMID: 29020859 PMCID: PMC5656109 DOI: 10.1177/1744806917737907] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Abstract Phosphatidylinositol 4-phosphate 5-kinase type 1 gamma (Pip5k1c) generates phosphatidylinositol 4,5-bisphosphate, also
known as PI(4,5)P2 or PIP2. Many pronociceptive signaling pathways and receptor tyrosine kinases signal via PIP2 hydrolysis.
Previously, we found that pain signaling and pain sensitization were reduced in Pip5k1cþ/ global heterozygous knockout
mice. Here, we sought to evaluate the extent to which dorsal root ganglia selective deletion of Pip5k1c affected nociception
in mice. Initially, we crossed sensory neuron-selective Advillin-Cre mice with a conditional Pip5k1c knockout (cKO) allele
(Pip5k1cfl/fl). However, these mice displayed an early onset proprioceptive deficit. To bypass this early onset phenotype,
we used two different tamoxifen-inducible Cre lines (Brn3a-Cre-ERT2 and Advillin-Cre-ERT2) to conditionally delete Pip5k1c in
adults. Tamoxifen induced high efficiency deletion of PIP5K1C in dorsal root ganglia and slightly reduced PIP5K1C in spinal
cord and brain in Brn3a-Cre-ERT2 Pip5k1cfl/fl (Brn3a cKO) mice while PIP5K1C was selectively deleted in dorsal root ganglia
with no changes in spinal cord or brain in Advillin-Cre-ERT2 Pip5k1cfl/fl (Advil cKO) mice. Acute thermosensation and
mechanosensation were not altered in either line relative to wild-type mice. However, thermal hypersensitivity and mechanical
allodynia recovered more rapidly in Brn3a cKO mice, but not Advil cKO mice, following hind paw inflammation.
These data collectively suggest that PIP5K1C regulates nociceptive sensitization in more regions of the nervous system
than dorsal root ganglia alone.
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Affiliation(s)
- Lipin Loo
- Department of Cell Biology and Physiology and UNC Neuroscience Center, The University of North Carolina, Chapel Hill, USA
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22
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Structural insights into lethal contractural syndrome type 3 (LCCS3) caused by a missense mutation of PIP5Kγ. Biochem J 2018; 475:2257-2269. [PMID: 29959184 DOI: 10.1042/bcj20180326] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Signaling molecule phosphatidylinositol 4,5-bisphosphate is produced primarily by phosphatidylinositol 4-phosphate 5-kinase (PIP5K). PIP5K is essential for the development of the human neuronal system, which has been exemplified by a recessive genetic disorder, lethal congenital contractural syndrome type 3, caused by a single aspartate-to-asparagine mutation in the kinase domain of PIP5Kγ. So far, the exact role of this aspartate residue has yet to be elucidated. In this work, we conducted structural, functional and computational studies on a zebrafish PIP5Kα variant with a mutation at the same site. Compared with the structure of the wild-type (WT) protein in the ATP-bound state, the ATP-associating glycine-rich loop of the mutant protein was severely disordered and the temperature factor of ATP was significantly higher. Both observations suggest a greater degree of disorder of the bound ATP, whereas neither the structure of the catalytic site nor the Km toward ATP was substantially affected by the mutation. Microsecond molecular dynamics simulation revealed that negative charge elimination caused by the mutation destabilized the involved hydrogen bonds and affected key electrostatic interactions in the close proximity of ATP. Taken together, our data indicated that the disease-related aspartate residue is a key node in the interaction network crucial for effective ATP binding. This work provides a paradigm of how a subtle but critical structural perturbation caused by a single mutation at the ATP-binding site abolishes the kinase activity, emphasizing that stabilizing substrate in a productive conformational state is crucial for catalysis.
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Lee JS, Sorcher JL, Rosen AD, Damadzic R, Sun H, Schwandt M, Heilig M, Kelly J, Mauro KL, Luo A, Rosoff D, Muench C, Jung J, Kaminsky ZA, Lohoff FW. Genetic Association and Expression Analyses of the Phosphatidylinositol-4-Phosphate 5-Kinase (PIP5K1C) Gene in Alcohol Use Disorder-Relevance for Pain Signaling and Alcohol Use. Alcohol Clin Exp Res 2018; 42:1034-1043. [PMID: 29667742 PMCID: PMC6134400 DOI: 10.1111/acer.13751] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 04/07/2018] [Indexed: 01/07/2023]
Abstract
BACKGROUND The gene encoding phosphatidylinositol-4-phosphate 5-kinase (PIP5K1C) has been recently implicated in pain regulation. Interestingly, a recent cross-tissue and cross-phenotypic epigenetic analysis identified the same gene in alcohol use disorder (AUD). Given the high comorbidity between AUD and chronic pain, we hypothesized that genetic variation in PIP5K1C might contribute to susceptibility to AUD. METHODS We conducted a case-control association study of genetic variants in PIP5K1C. Association analyses of 16 common PIP5K1C single nucleotide polymorphisms (SNPs) were conducted in cases and controls of African (427 cases and 137 controls) and European ancestry (488 cases and 324 controls) using standard methods. In addition, given the prominent role of the opioid system in pain signaling, we investigated the effects of acute alcohol exposure on PIP5K1C expression in humanized transgenic mice for the μ-opioid receptor that included the OPRM1 A118G polymorphism, a widely used mouse model to study analgesic response to opioids in pain. PIP5K1C expression was measured in the thalamus and basolateral amygdala (BLA) in mice after short-term administration (single 2 g/kg dose) of alcohol or saline using immunohistochemistry and analyzed by 2-way analysis of variance. RESULTS In the case-control association study using an NIAAA discovery sample, 8 SNPs in PIP5K1C were significantly associated with AUD in the African ancestry (AA) group (p < 0.05 after correction; rs4807493, rs10405681, rs2074957, rs10432303, rs8109485, rs1476592, rs10419980, and rs4432372). However, a replication analysis using an independent sample (N = 3,801) found no significant associations after correction for multiple testing. In the humanized transgenic mouse model with the OPRM1 polymorphism, PIP5K1C expression was significantly different between alcohol and saline-treated mice, regardless of genotype, in both the thalamus (p < 0.05) and BLA (p < 0.01). CONCLUSIONS Our discovery sample shows that genetic variants in PIP5K1C are associated with AUD in the AA group, and acute alcohol exposure leads to up-regulation of PIP5K1C, potentially explaining a mechanism underlying the increased risk for chronic pain conditions in individuals with AUD.
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Affiliation(s)
- Ji Soo Lee
- Section on Clinical Genomics and Experimental Therapeutics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD
| | - Jill L. Sorcher
- Section on Clinical Genomics and Experimental Therapeutics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD
| | - Allison D Rosen
- Section on Clinical Genomics and Experimental Therapeutics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD
| | - Ruslan Damadzic
- Office of the Clinical Director, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD
| | - Hui Sun
- Office of the Clinical Director, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD
| | - Melanie Schwandt
- Office of the Clinical Director, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD
| | | | - John Kelly
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Kelsey L Mauro
- Section on Clinical Genomics and Experimental Therapeutics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD
| | - Audrey Luo
- Section on Clinical Genomics and Experimental Therapeutics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD
| | - Daniel Rosoff
- Section on Clinical Genomics and Experimental Therapeutics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD
| | - Christine Muench
- Section on Clinical Genomics and Experimental Therapeutics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD
| | - Jeesun Jung
- Division of Intramural Clinical and Biological Research, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD
| | - Zachary A. Kaminsky
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Falk W. Lohoff
- Section on Clinical Genomics and Experimental Therapeutics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD
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24
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Smurf1 regulates lung cancer cell growth and migration through interaction with and ubiquitination of PIPKIγ. Oncogene 2017; 36:5668-5680. [DOI: 10.1038/onc.2017.166] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 03/31/2017] [Accepted: 04/26/2017] [Indexed: 12/12/2022]
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25
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Greene NDE, Leung KY, Copp AJ. Inositol, neural tube closure and the prevention of neural tube defects. Birth Defects Res 2017; 109:68-80. [PMID: 27324558 PMCID: PMC5353661 DOI: 10.1002/bdra.23533] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 04/24/2016] [Accepted: 05/08/2016] [Indexed: 12/29/2022]
Abstract
Susceptibility to neural tube defects (NTDs), such as anencephaly and spina bifida is influenced by genetic and environmental factors including maternal nutrition. Maternal periconceptional supplementation with folic acid significantly reduces the risk of an NTD-affected pregnancy, but does not prevent all NTDs, and "folic acid non-responsive" NTDs continue to occur. Similarly, among mouse models of NTDs, some are responsive to folic acid but others are not. Among nutritional factors, inositol deficiency causes cranial NTDs in mice while supplemental inositol prevents spinal and cranial NTDs in the curly tail (Grhl3 hypomorph) mouse, rodent models of hyperglycemia or induced diabetes, and in a folate-deficiency induced NTD model. NTDs also occur in mice lacking expression of certain inositol kinases. Inositol-containing phospholipids (phosphoinositides) and soluble inositol phosphates mediate a range of functions, including intracellular signaling, interaction with cytoskeletal proteins, and regulation of membrane identity in trafficking and cell division. Myo-inositol has been trialed in humans for a range of conditions and appears safe for use in human pregnancy. In pilot studies in Italy and the United Kingdom, women took inositol together with folic acid preconceptionally, after one or more previous NTD-affected pregnancies. In nonrandomized cohorts and a randomized double-blind study in the United Kingdom, no recurrent NTDs were observed among 52 pregnancies reported to date. Larger-scale fully powered trials are needed to determine whether supplementation with inositol and folic acid would more effectively prevent NTDs than folic acid alone. Birth Defects Research 109:68-80, 2017. © 2016 The Authors Birth Defects Research Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Nicholas D E Greene
- Newlife Birth Defects Research Centre and Developmental Biology & Cancer Programme, Institute of Child Health, University College London, London, United Kingdom
| | - Kit-Yi Leung
- Newlife Birth Defects Research Centre and Developmental Biology & Cancer Programme, Institute of Child Health, University College London, London, United Kingdom
| | - Andrew J Copp
- Newlife Birth Defects Research Centre and Developmental Biology & Cancer Programme, Institute of Child Health, University College London, London, United Kingdom
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26
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Mechanism of substrate specificity of phosphatidylinositol phosphate kinases. Proc Natl Acad Sci U S A 2016; 113:8711-6. [PMID: 27439870 PMCID: PMC4978281 DOI: 10.1073/pnas.1522112113] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The phosphatidylinositol phosphate kinase (PIPK) family of enzymes is primarily responsible for converting singly phosphorylated phosphatidylinositol derivatives to phosphatidylinositol bisphosphates. As such, these kinases are central to many signaling and membrane trafficking processes in the eukaryotic cell. The three types of phosphatidylinositol phosphate kinases are homologous in sequence but differ in catalytic activities and biological functions. Type I and type II kinases generate phosphatidylinositol 4,5-bisphosphate from phosphatidylinositol 4-phosphate and phosphatidylinositol 5-phosphate, respectively, whereas the type III kinase produces phosphatidylinositol 3,5-bisphosphate from phosphatidylinositol 3-phosphate. Based on crystallographic analysis of the zebrafish type I kinase PIP5Kα, we identified a structural motif unique to the kinase family that serves to recognize the monophosphate on the substrate. Our data indicate that the complex pattern of substrate recognition and phosphorylation results from the interplay between the monophosphate binding site and the specificity loop: the specificity loop functions to recognize different orientations of the inositol ring, whereas residues flanking the phosphate binding Arg244 determine whether phosphatidylinositol 3-phosphate is exclusively bound and phosphorylated at the 5-position. This work provides a thorough picture of how PIPKs achieve their exquisite substrate specificity.
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27
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Phosphatidylinositol phosphate kinase PIPKIγ and phosphatase INPP5E coordinate initiation of ciliogenesis. Nat Commun 2016; 7:10777. [PMID: 26916822 PMCID: PMC4773430 DOI: 10.1038/ncomms10777] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 01/19/2016] [Indexed: 02/08/2023] Open
Abstract
Defective primary cilia are causative to a wide spectrum of human genetic disorders, termed ciliopathies. Although the regulation of ciliogenesis is intensively studied, how it is initiated remains unclear. Here we show that type Iγ phosphatidylinositol 4-phosphate (PtdIns(4)P) 5-kinase (PIPKIγ) and inositol polyphosphate-5-phosphatase E (INPP5E), a Joubert syndrome protein, localize to the centrosome and coordinate the initiation of ciliogenesis. PIPKIγ counteracts INPP5E in regulating tau-tubulin kinase-2 (TTBK2) recruitment to the basal body, which promotes the removal of microtubule capping protein CP110 and the subsequent axoneme elongation. Interestingly, INPP5E and its product—PtdIns(4)P—accumulate at the centrosome/basal body in non-ciliated, but not ciliated, cells. PtdIns(4)P binding to TTBK2 and the distal appendage protein CEP164 compromises the TTBK2-CEP164 interaction and inhibits the recruitment of TTBK2. Our results reveal that PtdIns(4)P homoeostasis, coordinated by PIPKIγ and INPP5E at the centrosome/ciliary base, is vital for ciliogenesis by regulating the CEP164-dependent recruitment of TTBK2. The primary cilium is essential for embryonic development and tissue pattern formation. Here the authors show that PIPKIγ localizes to the basal body of the primary cilium and cooperates with the Joubert Syndrome associated protein INPP5E to regulate the initiation of ciliogenesis.
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Choi S, Anderson RA. IQGAP1 is a phosphoinositide effector and kinase scaffold. Adv Biol Regul 2015; 60:29-35. [PMID: 26554303 DOI: 10.1016/j.jbior.2015.10.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 10/05/2015] [Accepted: 10/06/2015] [Indexed: 01/16/2023]
Abstract
Phosphatidylinositol 4,5-bisphosphate (PI4,5P2) is a lipid messenger that regulates a wide variety of cellular functions. The majority of cellular PI4,5P2 is generated by isoforms of the type I phosphatidylinositol phosphate kinases (PIPKI) that are generated from three genes, and each PIPKI isoform has a unique distribution and function in cells. It has been shown that the signaling specificity of PI4,5P2 can be determined by a physical association of PIPKs with PI4,5P2 effectors. IQGAP1 is newly identified as an interactor of multiple isoforms of PIPKs. Considering the versatile roles of IQGAP1 in cellular signaling pathways, IQGAP1 may confer isoform-specific roles of PIPKs in distinct cellular locations. In this mini review, the emerging roles of PIPKs that are regulated by an association with IQGAP1 will be summarized. Focuses will be on cell migration, vesicle trafficking, cell signaling, and nuclear events.
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Affiliation(s)
- Suyong Choi
- University of Wisconsin-Madison, School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA
| | - Richard A Anderson
- University of Wisconsin-Madison, School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA.
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29
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Roybal KT, Mace EM, Mantell JM, Verkade P, Orange JS, Wülfing C. Early Signaling in Primary T Cells Activated by Antigen Presenting Cells Is Associated with a Deep and Transient Lamellal Actin Network. PLoS One 2015; 10:e0133299. [PMID: 26237050 PMCID: PMC4523204 DOI: 10.1371/journal.pone.0133299] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 06/25/2015] [Indexed: 01/21/2023] Open
Abstract
Cellular signaling transduction critically depends on molecular interactions that are in turn governed by dynamic subcellular distributions of the signaling system components. Comprehensive insight into signal transduction requires an understanding of such distributions and cellular structures driving them. To investigate the activation of primary murine T cells by antigen presenting cells (APC) we have imaged more than 60 signaling intermediates during T cell stimulation with microscopy across resolution limits. A substantial number of signaling intermediates associated with a transient, wide, and actin-associated lamellum extending from an interdigitated T cell:APC interface several micrometers into the T cell, as characterized in detail here. By mapping the more than 60 signaling intermediates onto the spatiotemporal features of cell biological structures, the lamellum and other ones previously described, we also define distinct spatial and temporal characteristics of T cell signal initiation, amplification, and core signaling in the activation of primary T cells by APCs. These characteristics differ substantially from ones seen when T cells are activated using common reductionist approaches.
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Affiliation(s)
- Kole T. Roybal
- Department of Immunology, UT Southwestern Medical Center, Dallas, Texas, United States of America
| | - Emily M. Mace
- Children's Hospital of Philadelphia Abramson Research Center, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Judith M. Mantell
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - Paul Verkade
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - Jordan S. Orange
- Children's Hospital of Philadelphia Abramson Research Center, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Christoph Wülfing
- Department of Immunology, UT Southwestern Medical Center, Dallas, Texas, United States of America
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, Texas, United States of America
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
- * E-mail:
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30
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Choi S, Thapa N, Tan X, Hedman AC, Anderson RA. PIP kinases define PI4,5P₂signaling specificity by association with effectors. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1851:711-23. [PMID: 25617736 PMCID: PMC4380618 DOI: 10.1016/j.bbalip.2015.01.009] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 01/14/2015] [Accepted: 01/16/2015] [Indexed: 12/21/2022]
Abstract
Phosphatidylinositol 4,5-bisphosphate (PI4,5P₂) is an essential lipid messenger with roles in all eukaryotes and most aspects of human physiology. By controlling the targeting and activity of its effectors, PI4,5P₂modulates processes, such as cell migration, vesicular trafficking, cellular morphogenesis, signaling and gene expression. In cells, PI4,5P₂has a much higher concentration than other phosphoinositide species and its total content is largely unchanged in response to extracellular stimuli. The discovery of a vast array of PI4,5P₂ binding proteins is consistent with data showing that the majority of cellular PI4,5P₂is sequestered. This supports a mechanism where PI4,5P₂functions as a localized and highly specific messenger. Further support of this mechanism comes from the de novo synthesis of PI4,5P₂which is often linked with PIP kinase interaction with PI4,5P₂effectors and is a mechanism to define specificity of PI4,5P₂signaling. The association of PI4,5P₂-generating enzymes with PI4,5P₂effectors regulate effector function both temporally and spatially in cells. In this review, the PI4,5P₂effectors whose functions are tightly regulated by associations with PI4,5P₂-generating enzymes will be discussed. This article is part of a Special Issue entitled Phosphoinositides.
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Affiliation(s)
- Suyong Choi
- Cellular and Molecular Biology Program, University of Wisconsin-Madison, School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA
| | - Narendra Thapa
- Molecular and Cellular Pharmacology Program, University of Wisconsin-Madison, School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA
| | - Xiaojun Tan
- Molecular and Cellular Pharmacology Program, University of Wisconsin-Madison, School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA
| | - Andrew C Hedman
- Molecular and Cellular Pharmacology Program, University of Wisconsin-Madison, School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA
| | - Richard A Anderson
- Cellular and Molecular Biology Program, University of Wisconsin-Madison, School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA; Molecular and Cellular Pharmacology Program, University of Wisconsin-Madison, School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA.
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31
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Wright BD, Loo L, Street SE, Ma A, Taylor-Blake B, Stashko MA, Jin J, Janzen WP, Frye SV, Zylka MJ. The lipid kinase PIP5K1C regulates pain signaling and sensitization. Neuron 2014; 82:836-47. [PMID: 24853942 DOI: 10.1016/j.neuron.2014.04.006] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/24/2014] [Indexed: 02/07/2023]
Abstract
Numerous pain-producing (pronociceptive) receptors signal via phosphatidylinositol 4,5-bisphosphate (PIP2) hydrolysis. However, it is currently unknown which lipid kinases generate PIP2 in nociceptive dorsal root ganglia (DRG) neurons and if these kinases regulate pronociceptive receptor signaling. Here, we found that phosphatidylinositol 4-phosphate 5 kinase type 1C (PIP5K1C) is expressed at higher levels than any other PIP5K and, based on experiments with Pip5k1c(+/-) mice, generates at least half of all PIP2 in DRG neurons. Additionally, Pip5k1c haploinsufficiency reduces pronociceptive receptor signaling and TRPV1 sensitization in DRG neurons as well as thermal and mechanical hypersensitivity in mouse models of chronic pain. We identified a small molecule inhibitor of PIP5K1C (UNC3230) in a high-throughput screen. UNC3230 lowered PIP2 levels in DRG neurons and attenuated hypersensitivity when administered intrathecally or into the hindpaw. Our studies reveal that PIP5K1C regulates PIP2-dependent nociceptive signaling and suggest that PIP5K1C is a therapeutic target for chronic pain.
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Affiliation(s)
- Brittany D Wright
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Cell Biology and Physiology, UNC Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Lipin Loo
- Department of Cell Biology and Physiology, UNC Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Sarah E Street
- Department of Cell Biology and Physiology, UNC Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Anqi Ma
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Center for Integrative Chemical Biology and Drug Discovery, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Bonnie Taylor-Blake
- Department of Cell Biology and Physiology, UNC Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Michael A Stashko
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Center for Integrative Chemical Biology and Drug Discovery, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jian Jin
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Center for Integrative Chemical Biology and Drug Discovery, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - William P Janzen
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Center for Integrative Chemical Biology and Drug Discovery, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Stephen V Frye
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Center for Integrative Chemical Biology and Drug Discovery, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Mark J Zylka
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Cell Biology and Physiology, UNC Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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Enrichment of phosphatidylinositols with specific acyl chains. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:1501-8. [DOI: 10.1016/j.bbamem.2013.10.003] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Revised: 09/25/2013] [Accepted: 10/03/2013] [Indexed: 12/21/2022]
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Roybal KT, Sinai P, Verkade P, Murphy RF, Wülfing C. The actin-driven spatiotemporal organization of T-cell signaling at the system scale. Immunol Rev 2014; 256:133-47. [PMID: 24117818 DOI: 10.1111/imr.12103] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
T cells are activated through interaction with antigen-presenting cells (APCs). During activation, receptors and signaling intermediates accumulate in diverse spatiotemporal distributions. These distributions control the probability of signaling interactions and thus govern information flow through the signaling system. Spatiotemporally resolved system-scale investigation of signaling can extract the regulatory information thus encoded, allowing unique insight into the control of T-cell function. Substantial technical challenges exist, and these are briefly discussed herein. While much of the work assessing T-cell spatiotemporal organization uses planar APC substitutes, we focus here on B-cell APCs with often stark differences. Spatiotemporal signaling distributions are driven by cell biologically distinct structures, a large protein assembly at the interface center, a large invagination, the actin-supported interface periphery as extended by smaller individual lamella, and a newly discovered whole-interface actin-driven lamellum. The more than 60 elements of T-cell activation studied to date are dynamically distributed between these structures, generating a complex organization of the signaling system. Signal initiation and core signaling prefer the interface center, while signal amplification is localized in the transient lamellum. Actin dynamics control signaling distributions through regulation of the underlying structures and drive a highly undulating T-cell/APC interface that imposes substantial constraints on T-cell organization. We suggest that the regulation of actin dynamics, by controlling signaling distributions and membrane topology, is an important rheostat of T-cell signaling.
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Affiliation(s)
- Kole T Roybal
- Department of Immunology, UT Southwestern Medical Center, Dallas, TX, USA
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Kappen C. Modeling anterior development in mice: diet as modulator of risk for neural tube defects. AMERICAN JOURNAL OF MEDICAL GENETICS. PART C, SEMINARS IN MEDICAL GENETICS 2013; 163C:333-56. [PMID: 24124024 PMCID: PMC4149464 DOI: 10.1002/ajmg.c.31380] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Head morphogenesis is a complex process that is controlled by multiple signaling centers. The most common defects of cranial development are craniofacial defects, such as cleft lip and cleft palate, and neural tube defects, such as anencephaly and encephalocoele in humans. More than 400 genes that contribute to proper neural tube closure have been identified in experimental animals, but only very few causative gene mutations have been identified in humans, supporting the notion that environmental influences are critical. The intrauterine environment is influenced by maternal nutrition, and hence, maternal diet can modulate the risk for cranial and neural tube defects. This article reviews recent progress toward a better understanding of nutrients during pregnancy, with particular focus on mouse models for defective neural tube closure. At least four major patterns of nutrient responses are apparent, suggesting that multiple pathways are involved in the response, and likely in the underlying pathogenesis of the defects. Folic acid has been the most widely studied nutrient, and the diverse responses of the mouse models to folic acid supplementation indicate that folic acid is not universally beneficial, but that the effect is dependent on genetic configuration. If this is the case for other nutrients as well, efforts to prevent neural tube defects with nutritional supplementation may need to become more specifically targeted than previously appreciated. Mouse models are indispensable for a better understanding of nutrient-gene interactions in normal pregnancies, as well as in those affected by metabolic diseases, such as diabetes and obesity.
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Soluble VCAM-1 Alters Lipid Phosphatase Activity in Epicardial Mesothelial Cells: Implications for Lipid Signaling During Epicardial Formation. J Dev Biol 2013. [DOI: 10.3390/jdb1020159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Choi S, Thapa N, Hedman AC, Li Z, Sacks DB, Anderson RA. IQGAP1 is a novel phosphatidylinositol 4,5 bisphosphate effector in regulation of directional cell migration. EMBO J 2013; 32:2617-30. [PMID: 23982733 DOI: 10.1038/emboj.2013.191] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 07/29/2013] [Indexed: 12/15/2022] Open
Abstract
Phosphatidylinositol 4,5 bisphosphate (PIP₂) is a key lipid messenger for regulation of cell migration. PIP₂ modulates many effectors, but the specificity of PIP₂ signalling can be defined by interactions of PIP₂-generating enzymes with PIP₂ effectors. Here, we show that type Iγ phosphatidylinositol 4-phosphate 5-kinase (PIPKIγ) interacts with the cytoskeleton regulator, IQGAP1, and modulates IQGAP1 function in migration. We reveal that PIPKIγ is required for IQGAP1 recruitment to the leading edge membrane in response to integrin or growth factor receptor activation. Moreover, IQGAP1 is a PIP₂ effector that directly binds PIP₂ through a polybasic motif and PIP₂ binding activates IQGAP1, facilitating actin polymerization. IQGAP1 mutants that lack PIPKIγ or PIP₂ binding lose the ability to control directional cell migration. Collectively, these data reveal a synergy between PIPKIγ and IQGAP1 in the control of cell migration.
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Affiliation(s)
- Suyong Choi
- Cellular and Molecular Biology Graduate Program, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, USA
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37
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Bayot A, Reichman S, Lebon S, Csaba Z, Aubry L, Sterkers G, Husson I, Rak M, Rustin P. Cis-silencing of PIP5K1B evidenced in Friedreich's ataxia patient cells results in cytoskeleton anomalies. Hum Mol Genet 2013; 22:2894-904. [PMID: 23552101 DOI: 10.1093/hmg/ddt144] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Friedreich's ataxia (FRDA) is a progressive neurodegenerative disease characterized by ataxia, variously associating heart disease, diabetes mellitus and/or glucose intolerance. It results from intronic expansion of GAA triplet repeats at the FXN locus. Homozygous expansions cause silencing of the FXN gene and subsequent decreased expression of the encoded mitochondrial frataxin. Detailed analyses in fibroblasts and neuronal tissues from FRDA patients have revealed profound cytoskeleton anomalies. So far, however, the molecular mechanism underlying these cytoskeleton defects remains unknown. We show here that gene silencing spreads in cis over the PIP5K1B gene in cells from FRDA patients (circulating lymphocytes and primary fibroblasts), correlating with expanded GAA repeat size. PIP5K1B encodes phosphatidylinositol 4-phosphate 5-kinase β type I (pip5k1β), an enzyme functionally linked to actin cytoskeleton dynamics that phosphorylates phosphatidylinositol 4-phosphate [PI(4)P] to generate phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2]. Accordingly, loss of pip5k1β function in FRDA cells was accompanied by decreased PI(4,5)P2 levels and was shown instrumental for destabilization of the actin network and delayed cell spreading. Knockdown of PIP5K1B in control fibroblasts using shRNA reproduced abnormal actin cytoskeleton remodeling, whereas over-expression of PIP5K1B, but not FXN, suppressed this phenotype in FRDA cells. In addition to provide new insights into the consequences of the FXN gene expansion, these findings raise the question whether PIP5K1B silencing may contribute to the variable manifestation of this complex disease.
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Affiliation(s)
- Aurélien Bayot
- Hôpital Robert Debré, INSERM UMR 676 Faculté de Médecine Denis Diderot, Université Paris 7, 75019 Paris, France.
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Abstract
Phosphoinositides (PIs) make up only a small fraction of cellular phospholipids, yet they control almost all aspects of a cell's life and death. These lipids gained tremendous research interest as plasma membrane signaling molecules when discovered in the 1970s and 1980s. Research in the last 15 years has added a wide range of biological processes regulated by PIs, turning these lipids into one of the most universal signaling entities in eukaryotic cells. PIs control organelle biology by regulating vesicular trafficking, but they also modulate lipid distribution and metabolism via their close relationship with lipid transfer proteins. PIs regulate ion channels, pumps, and transporters and control both endocytic and exocytic processes. The nuclear phosphoinositides have grown from being an epiphenomenon to a research area of its own. As expected from such pleiotropic regulators, derangements of phosphoinositide metabolism are responsible for a number of human diseases ranging from rare genetic disorders to the most common ones such as cancer, obesity, and diabetes. Moreover, it is increasingly evident that a number of infectious agents hijack the PI regulatory systems of host cells for their intracellular movements, replication, and assembly. As a result, PI converting enzymes began to be noticed by pharmaceutical companies as potential therapeutic targets. This review is an attempt to give an overview of this enormous research field focusing on major developments in diverse areas of basic science linked to cellular physiology and disease.
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Affiliation(s)
- Tamas Balla
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
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Hara Y, Fukaya M, Tamaki H, Sakagami H. Type I phosphatidylinositol 4-phosphate 5-kinase γ is required for neuronal migration in the mouse developing cerebral cortex. Eur J Neurosci 2013; 38:2659-71. [DOI: 10.1111/ejn.12286] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 05/27/2013] [Accepted: 05/29/2013] [Indexed: 01/04/2023]
Affiliation(s)
- Yoshinobu Hara
- Department of Anatomy; Kitasato University School of Medicine; 1-15-1 Kitasato; Sagamihara; Kanagawa; 252-0374; Japan
| | - Masahiro Fukaya
- Department of Anatomy; Kitasato University School of Medicine; 1-15-1 Kitasato; Sagamihara; Kanagawa; 252-0374; Japan
| | - Hideaki Tamaki
- Department of Anatomy; Kitasato University School of Medicine; 1-15-1 Kitasato; Sagamihara; Kanagawa; 252-0374; Japan
| | - Hiroyuki Sakagami
- Department of Anatomy; Kitasato University School of Medicine; 1-15-1 Kitasato; Sagamihara; Kanagawa; 252-0374; Japan
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40
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Sun Y, Thapa N, Hedman AC, Anderson RA. Phosphatidylinositol 4,5-bisphosphate: targeted production and signaling. Bioessays 2013; 35:513-22. [PMID: 23575577 DOI: 10.1002/bies.201200171] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Phosphatidylinositol 4,5-bisphosphate (PI4,5P(2)) is a key lipid signaling molecule that regulates a vast array of biological activities. PI4,5P(2) can act directly as a messenger or can be utilized as a precursor to generate other messengers: inositol trisphosphate, diacylglycerol, or phosphatidylinositol 3,4,5-trisphosphate. PI4,5P(2) interacts with hundreds of different effector proteins. The enormous diversity of PI4,5P(2) effector proteins and the spatio-temporal control of PI4,5P(2) generation allow PI4,5P(2) signaling to control a broad spectrum of cellular functions. PI4,5P(2) is synthesized by phosphatidylinositol phosphate kinases (PIPKs). The array of PIPKs in cells enables their targeting to specific subcellular compartments through interactions with targeting factors that are often PI4,5P(2) effectors. These interactions are a mechanism to define spatial and temporal PI4,5P(2) synthesis and the specificity of PI4,5P(2) signaling. In turn, the regulation of PI4,5P(2) effectors at specific cellular compartments has implications for understanding how PI4,5P(2) controls cellular processes and its role in diseases.
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Affiliation(s)
- Yue Sun
- University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, USA
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41
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Wang Y, Zhao L, Suzuki A, Lian L, Min SH, Wang Z, Litvinov RI, Stalker TJ, Yago T, Klopocki AG, Schmidtke DW, Yin H, Choi JK, McEver RP, Weisel JW, Hartwig JH, Abrams CS. Platelets lacking PIP5KIγ have normal integrin activation but impaired cytoskeletal-membrane integrity and adhesion. Blood 2013; 121:2743-52. [PMID: 23372168 PMCID: PMC3617636 DOI: 10.1182/blood-2012-07-445205] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 01/20/2013] [Indexed: 11/20/2022] Open
Abstract
Three isoforms of phosphatidylinositol-4-phosphate 5-kinase (PIP5KIα, PIP5KIβ, and PIP5KIγ) can each catalyze the final step in the synthesis of phosphatidylinositol-4,5-bisphosphate (PIP2), which in turn can be either converted to second messengers or bind directly to and thereby regulate proteins such as talin. A widely quoted model speculates that only p90, a longer splice form of platelet-specific PIP5KIγ, but not the shorter p87 PIP5KIγ, regulates the ligand-binding activity of integrins via talin. However, when we used mice genetically engineered to lack only p90 PIP5KIγ, we found that p90 PIP5KIγ is not critical for integrin activation or platelet adhesion on collagen. However, p90 PIP5KIγ-null platelets do have impaired anchoring of their integrins to the underlying cytoskeleton. Platelets lacking both the p90 and p87 PIP5KIγ isoforms had normal integrin activation and actin dynamics, but impaired anchoring of their integrins to the cytoskeleton. Most importantly, they formed weak shear-resistant adhesions ex vivo and unstable vascular occlusions in vivo. Together, our studies demonstrate that, although PIP5KIγ is essential for normal platelet function, individual isoforms of PIP5KIγ fulfill unique roles for the integrin-dependent integrity of the membrane cytoskeleton and for the stabilization of platelet adhesion.
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Affiliation(s)
- Yanfeng Wang
- Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
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Zohn IE. Mouse as a model for multifactorial inheritance of neural tube defects. ACTA ACUST UNITED AC 2012; 96:193-205. [PMID: 22692891 DOI: 10.1002/bdrc.21011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Neural tube defects (NTDs) such as spina bifida and anencephaly are some of the most common structural birth defects found in humans. These defects occur due to failures of neurulation, a process where the flat neural plate rolls into a tube. In spite of their prevalence, the causes of NTDs are poorly understood. The multifactorial threshold model best describes the pattern of inheritance of NTDs where multiple undefined gene variants interact with environmental factors to cause an NTD. To date, mouse models have implicated a multitude of genes as required for neurulation, providing a mechanistic understanding of the cellular and molecular pathways that control neurulation. However, the majority of these mouse models exhibit NTDs with a Mendelian pattern of inheritance. Still, many examples of multifactorial inheritance have been demonstrated in mouse models of NTDs. These include null and hypomorphic alleles of neurulation genes that interact in a complex fashion with other genetic mutations or environmental factors to cause NTDs. These models have implicated several genes and pathways for testing as candidates for the genetic basis of NTDs in humans, resulting in identification of putative pathogenic mutations in some patients. Mouse models also provide an experimental paradigm to gain a mechanistic understanding of the environmental factors that influence NTD occurrence, such as folic acid and maternal diabetes, and have led to the discovery of additional preventative nutritional supplements such as inositol. This review provides examples of how multifactorial inheritance of NTDs can be modeled in the mouse.
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Affiliation(s)
- Irene E Zohn
- Center for Neuroscience Research, Children's Research Institute, Children's National Medical Center, Washington, DC 20010, USA.
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43
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Phosphatidylinositol 4-Kinases and PI4P Metabolism in the Nervous System: Roles in Psychiatric and Neurological Diseases. Mol Neurobiol 2012; 47:361-72. [DOI: 10.1007/s12035-012-8358-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 09/27/2012] [Indexed: 01/18/2023]
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Legate KR, Montag D, Böttcher RT, Takahashi S, Fässler R. Comparative phenotypic analysis of the two major splice isoforms of phosphatidylinositol phosphate kinase type Iγ in vivo. J Cell Sci 2012; 125:5636-46. [PMID: 22976293 DOI: 10.1242/jcs.102145] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Localized production of polyphosphoinositides is critical for their signaling function. To examine the biological relevance of specific pools of phosphatidylinositol 4,5-bisphosphate we compared the consequences of genetically ablating all isoforms of phosphatidylinositol phosphate (PIP) kinase type Iγ (PIPKIγ), encoded by the gene Pip5k1c, versus ablation of a specific splice isoform, PIPKIγ_i2, with respect to three reported PIPKIγ functions. Ablation of PIPKIγ_i2 caused a neuron-specific endocytosis defect similar to that found in PIPKIγ(-/-) mice, while agonist-induced calcium signaling was reduced in PIPKIγ(-/-) cells, but was not affected in the absence of PIPKIγ_i2. A reported contribution of PIPKIγ to epithelial integrity was not evident in PIPKIγ(-/-) mice. Given that mice lacking PIPKIγ_i2 live a normal lifespan whereas PIPKIγ(-/-) mice die shortly after birth, we propose that PIPKIγ-mediated metabotropic calcium signaling may represent an essential function of PIPKIγ, whereas functions specific to the PIPKIγ_i2 splice isoform are not essential for survival.
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Affiliation(s)
- Kyle R Legate
- Department of Molecular Medicine, Max Planck Institute of Biochemistry, Martinsried, 82152 Germany
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45
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Thapa N, Anderson RA. PIP2 signaling, an integrator of cell polarity and vesicle trafficking in directionally migrating cells. Cell Adh Migr 2012; 6:409-12. [PMID: 23076053 PMCID: PMC3496677 DOI: 10.4161/cam.21192] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Cell migration is a fundamental cellular process required for embryonic development to wound healing and also plays a key role in tumor metastasis and atherosclerosis. Migration is regulated at multiple strata, from cytoskeletal reorganization to vesicle trafficking. In migrating cells, signaling pathways are integrated with vesicle trafficking machineries in a highly coordinated fashion to accomplish the recruitment and trafficking of the trans-membrane proteins toward the leading edge. Different signaling molecules regulate cell migration in different physio-pathological contexts, among them, phosphatidylinositol-4,5-biphosphate (PIP2) is an integral component of the plasma membrane and pleiotropic lipid signaling molecule modulating diverse biological processes, including actin cytoskeletal dynamics and vesicle trafficking required for cell migration. In this commentary, we provide a brief overview of our current understandings on the phosphoinositide signaling and its implication in regulation of cell polarity and vesicle trafficking in migrating cells. In addition, we highlight the coordinated role of PIPKIγi2, a focal adhesion-targeted enzyme that synthesizes PIP2, and the exocyst complex, a PIP2-effector, in the trafficking of E-cadherin in epithelial cells and integrins in migrating cancer cells.
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Affiliation(s)
- Narendra Thapa
- Molecular and Cellular Pharmacology Program, School of Medicine and Public Health, University of Wisconsin-Madison; Madison, WI, USA
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46
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Reduced phosphatidylinositol 4,5-bisphosphate synthesis impairs inner ear Ca2+ signaling and high-frequency hearing acquisition. Proc Natl Acad Sci U S A 2012; 109:14013-8. [PMID: 22891314 DOI: 10.1073/pnas.1211869109] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Phosphatidylinositol phosphate kinase type 1γ (PIPKIγ) is a key enzyme in the generation of phosphatidylinositol 4,5-bisphosphate [PI(4,5)P(2)] and is expressed at high levels in the nervous system. Homozygous knockout mice lacking this enzyme die postnatally within 24 h, whereas PIPKIγ(+/-) siblings breed normally and have no reported phenotype. Here we show that adult PIPKIγ(+/-) mice have dramatically elevated hearing thresholds for high-frequency sounds. During the first postnatal week we observed a reduction of ATP-dependent Ca(2+) signaling activity in cochlear nonsensory cells. Because Ca(2+) signaling under these conditions depends on inositol-1,4,5-trisphosphate generation from phospholipase C (PLC)-dependent hydrolysis of PI(4,5)P(2), we conclude that (i) PIPKIγ is primarily responsible for the synthesis of the receptor-regulated PLC-sensitive PI(4,5)P(2) pool in the cell syncytia that supports auditory hair cells; (ii) spatially graded impairment of this signaling pathway in cochlear nonsensory cells causes a selective alteration in the acquisition of hearing in PIPKIγ(+/-) mice. This mouse model also suggests that PIPKIγ may determine the level of gap junction contribution to cochlear development.
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47
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De Grazia S, Carlomagno G, Unfer V, Cavalli P. Myo-inositol soft gel capsules may prevent the risk of coffee-induced neural tube defects. Expert Opin Drug Deliv 2012; 9:1033-9. [DOI: 10.1517/17425247.2012.701616] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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48
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Hasegawa H, Noguchi J, Yamashita M, Okada R, Sugimoto R, Furuya M, Unoki T, Funakoshi Y, Baba T, Kanaho Y. Phosphatidylinositol 4-Phosphate 5-Kinase Is Indispensable for Mouse Spermatogenesis1. Biol Reprod 2012; 86:136, 1-12. [DOI: 10.1095/biolreprod.110.089896] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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Mukhopadhyay P, Brock G, Webb C, Pisano MM, Greene RM. Strain-specific modifier genes governing craniofacial phenotypes. ACTA ACUST UNITED AC 2012; 94:162-75. [PMID: 22371338 DOI: 10.1002/bdra.22890] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 12/12/2011] [Accepted: 12/13/2011] [Indexed: 01/06/2023]
Abstract
BACKGROUND The presence of strain-specific modifier genes is known to modulate the phenotype and pathophysiology of mice harboring genetically engineered mutations. Thus, identification of genetic modifier genes is requisite to understanding control of phenotypic expression. c-Ski is a transcriptional regulator. Ski(-/-) mice on a C57BL6J (B6) background exhibit facial clefting, while Ski(-/-) mice on a 129P3 (129) background present with exencephaly. METHODS In the present study, oligonucleotide-based gene expression profiling was used to identify potential strain-specific modifier gene candidates present in wild type mice of B6 and 129 genetic backgrounds. Changes in gene expression were verified by TaqMan quantitative real-time PCR. RESULTS Steady-state levels of 89 genes demonstrated a significantly higher level of expression, and those of 68 genes demonstrated a significantly lower level of expression in the developing neural tubes from embryonic day (E) 8.5, B6 embryos when compared to expression levels in neural tubes derived from E 8.5, 129 embryos. CONCLUSIONS Based on the results from the current comparative microarray study, and taking into consideration a number of relevant published reports, several potential strain-specific gene candidates, likely to modify the craniofacial phenotypes in various knockout mouse models have been identified.
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Affiliation(s)
- Partha Mukhopadhyay
- University of Louisville Birth Defects Center, Department of Molecular, Cellular and Craniofacial Biology, ULSD, University of Louisville, Louisville, Kentucky 40292, USA
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Legate KR, Takahashi S, Bonakdar N, Fabry B, Boettiger D, Zent R, Fässler R. Integrin adhesion and force coupling are independently regulated by localized PtdIns(4,5)2 synthesis. EMBO J 2012; 30:4539-53. [PMID: 21926969 DOI: 10.1038/emboj.2011.332] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2011] [Accepted: 08/19/2011] [Indexed: 01/23/2023] Open
Abstract
The 90-kDa isoform of the lipid kinase PIP kinase Type I γ (PIPKIγ) localizes to focal adhesions (FAs), where it provides a local source of phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P(2)). Although PtdIns(4,5)P(2) regulates the function of several FA-associated molecules, the role of the FA-specific pool of PtdIns(4,5)P(2) is not known. We report that the genetic ablation of PIPKIγ specifically from FAs results in defective integrin-mediated adhesion and force coupling. Adhesion defects in cells deficient in FAPtdIns(4,5)P(2) synthesis are corrected within minutes while integrin-actin force coupling remains defective over a longer period. Talin and vinculin, but not kindlin, are less efficiently recruited to new adhesions in these cells. These data demonstrate that the specific depletion of PtdIns(4,5)P(2) from FAs temporally separates integrin-ligand binding from integrin-actin force coupling by regulating talin and vinculin recruitment. Furthermore, it suggests that force coupling relies heavily on locally generated PtdIns(4,5)P(2) rather than bulk membrane PtdIns(4,5)P(2).
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Affiliation(s)
- Kyle R Legate
- Department of Molecular Medicine, Max Planck Institute of Biochemistry, Martinsried, Germany
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