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Wang W, Xie Y, Liu L, King GJ, White P, Ding G, Wang S, Cai H, Wang C, Xu F, Shi L. Genetic Control of Seed Phytate Accumulation and the Development of Low-Phytate Crops: A Review and Perspective. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:3375-3390. [PMID: 35275483 DOI: 10.1021/acs.jafc.1c06831] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Breeding low phytic acid (lpa) crops is a strategy that has potential to both improve the nutritional quality of food and feed and contribute to the sustainability of agriculture. Here, we review the lipid-independent and -dependent pathways of phytate synthesis and their regulatory mechanisms in plants. We compare the genetic variation of the phytate concentration and distribution in seeds between dicot and monocot species as well as the associated temporal and spatial expression patterns of the genes involved in phytate synthesis and transport. Quantitative trait loci or significant single nucleotide polymorphisms for the seed phytate concentration have been identified in different plant species by linkage and association mapping, and some genes have been cloned from lpa mutants. We summarize the effects of various lpa mutations on important agronomic traits in crop plants and propose SULTR3;3 and SULTR3;4 as optimal target genes for lpa crop breeding.
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Affiliation(s)
- Wei Wang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei 430070, People's Republic of China
- Microelement Research Center, Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, Hubei 430070, People's Republic of China
| | - Yiwen Xie
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei 430070, People's Republic of China
- Microelement Research Center, Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, Hubei 430070, People's Republic of China
| | - Lei Liu
- Southern Cross Plant Science, Southern Cross University, Lismore New South Wales 2480, Australia
| | - Graham J King
- Southern Cross Plant Science, Southern Cross University, Lismore New South Wales 2480, Australia
| | - Philip White
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei 430070, People's Republic of China
- The James Hutton Institute, Invergowrie, Dundee DD2 5DA, United Kingdom
| | - Guangda Ding
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei 430070, People's Republic of China
- Microelement Research Center, Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, Hubei 430070, People's Republic of China
| | - Sheliang Wang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei 430070, People's Republic of China
- Microelement Research Center, Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, Hubei 430070, People's Republic of China
| | - Hongmei Cai
- Microelement Research Center, Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, Hubei 430070, People's Republic of China
| | - Chuang Wang
- Microelement Research Center, Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, Hubei 430070, People's Republic of China
| | - Fangsen Xu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei 430070, People's Republic of China
- Microelement Research Center, Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, Hubei 430070, People's Republic of China
| | - Lei Shi
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei 430070, People's Republic of China
- Microelement Research Center, Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, Hubei 430070, People's Republic of China
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McLaren MD, Mathavarajah S, Kim WD, Yap SQ, Huber RJ. Aberrant Autophagy Impacts Growth and Multicellular Development in a Dictyostelium Knockout Model of CLN5 Disease. Front Cell Dev Biol 2021; 9:657406. [PMID: 34291044 PMCID: PMC8287835 DOI: 10.3389/fcell.2021.657406] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 05/28/2021] [Indexed: 12/22/2022] Open
Abstract
Mutations in CLN5 cause a subtype of neuronal ceroid lipofuscinosis (NCL) called CLN5 disease. While the precise role of CLN5 in NCL pathogenesis is not known, recent work revealed that the protein has glycoside hydrolase activity. Previous work on the Dictyostelium discoideum homolog of human CLN5, Cln5, revealed its secretion during the early stages of development and its role in regulating cell adhesion and cAMP-mediated chemotaxis. Here, we used Dictyostelium to examine the effect of cln5-deficiency on various growth and developmental processes during the life cycle. During growth, cln5– cells displayed reduced cell proliferation, cytokinesis, viability, and folic acid-mediated chemotaxis. In addition, the growth of cln5– cells was severely impaired in nutrient-limiting media. Based on these findings, we assessed autophagic flux in growth-phase cells and observed that loss of cln5 increased the number of autophagosomes suggesting that the basal level of autophagy was increased in cln5– cells. Similarly, loss of cln5 increased the amounts of ubiquitin-positive proteins. During the early stages of multicellular development, the aggregation of cln5– cells was delayed and loss of the autophagy genes, atg1 and atg9, reduced the extracellular amount of Cln5. We also observed an increased amount of intracellular Cln5 in cells lacking the Dictyostelium homolog of the human glycoside hydrolase, hexosaminidase A (HEXA), further supporting the glycoside hydrolase activity of Cln5. This observation was also supported by our finding that CLN5 and HEXA expression are highly correlated in human tissues. Following mound formation, cln5– development was precocious and loss of cln5 affected spore morphology, germination, and viability. When cln5– cells were developed in the presence of the autophagy inhibitor ammonium chloride, the formation of multicellular structures was impaired, and the size of cln5– slugs was reduced relative to WT slugs. These results, coupled with the aberrant autophagic flux observed in cln5– cells during growth, support a role for Cln5 in autophagy during the Dictyostelium life cycle. In total, this study highlights the multifaceted role of Cln5 in Dictyostelium and provides insight into the pathological mechanisms that may underlie CLN5 disease.
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Affiliation(s)
- Meagan D McLaren
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON, Canada
| | | | - William D Kim
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON, Canada
| | - Shyong Q Yap
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON, Canada
| | - Robert J Huber
- Department of Biology, Trent University, Peterborough, ON, Canada
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Rojas-Pirela M, Andrade-Alviárez D, Rojas V, Kemmerling U, Cáceres AJ, Michels PA, Concepción JL, Quiñones W. Phosphoglycerate kinase: structural aspects and functions, with special emphasis on the enzyme from Kinetoplastea. Open Biol 2020; 10:200302. [PMID: 33234025 PMCID: PMC7729029 DOI: 10.1098/rsob.200302] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Phosphoglycerate kinase (PGK) is a glycolytic enzyme that is well conserved among the three domains of life. PGK is usually a monomeric enzyme of about 45 kDa that catalyses one of the two ATP-producing reactions in the glycolytic pathway, through the conversion of 1,3-bisphosphoglycerate (1,3BPGA) to 3-phosphoglycerate (3PGA). It also participates in gluconeogenesis, catalysing the opposite reaction to produce 1,3BPGA and ADP. Like most other glycolytic enzymes, PGK has also been catalogued as a moonlighting protein, due to its involvement in different functions not associated with energy metabolism, which include pathogenesis, interaction with nucleic acids, tumorigenesis progression, cell death and viral replication. In this review, we have highlighted the overall aspects of this enzyme, such as its structure, reaction kinetics, activity regulation and possible moonlighting functions in different protistan organisms, especially both free-living and parasitic Kinetoplastea. Our analysis of the genomes of different kinetoplastids revealed the presence of open-reading frames (ORFs) for multiple PGK isoforms in several species. Some of these ORFs code for unusually large PGKs. The products appear to contain additional structural domains fused to the PGK domain. A striking aspect is that some of these PGK isoforms are predicted to be catalytically inactive enzymes or ‘dead’ enzymes. The roles of PGKs in kinetoplastid parasites are analysed, and the apparent significance of the PGK gene duplication that gave rise to the different isoforms and their expression in Trypanosoma cruzi is discussed.
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Affiliation(s)
- Maura Rojas-Pirela
- Instituto de Biología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaiso, Valparaiso 2373223, Chile
| | - Diego Andrade-Alviárez
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela
| | - Verónica Rojas
- Instituto de Biología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaiso, Valparaiso 2373223, Chile
| | - Ulrike Kemmerling
- Instituto de Ciencias Biomédicas, Universidad de Chile, Facultad de Medicina, Santiago de Chile 8380453, Santigo de Chile
| | - Ana J Cáceres
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela
| | - Paul A Michels
- Centre for Immunity, Infection and Evolution, The King's Buildings, Edinburgh EH9 3FL, UK.,Centre for Translational and Chemical Biology, School of Biological Sciences, The University of Edinburgh, The King's Buildings, Edinburgh EH9 3FL, UK
| | - Juan Luis Concepción
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela
| | - Wilfredo Quiñones
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela
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ITPK1 mediates the lipid-independent synthesis of inositol phosphates controlled by metabolism. Proc Natl Acad Sci U S A 2019; 116:24551-24561. [PMID: 31754032 PMCID: PMC6900528 DOI: 10.1073/pnas.1911431116] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Inositol phosphates (IPs) are a class of signaling molecules regulating cell physiology. The best-characterized IP, the calcium release factor IP3, is generated by phospholipase C hydrolysis of phosphoinositides lipids. For historical and technical reasons, IPs synthesis is believed to originate from the lipid-generated IP3. While this is true in yeast, our work has demonstrated that other organisms use a “soluble” (nonlipid) route to synthesize IPs. This soluble pathway depends on the metabolic status of the cells, and is under the control of the kinase ITPK1, which phosphorylates inositol monophosphate likely generated from glucose. The data shed light on the evolutionary origin of IPs, signaling and tightening the link between these small molecules and basic metabolism. Inositol phosphates (IPs) comprise a network of phosphorylated molecules that play multiple signaling roles in eukaryotes. IPs synthesis is believed to originate with IP3 generated from PIP2 by phospholipase C (PLC). Here, we report that in mammalian cells PLC-generated IPs are rapidly recycled to inositol, and uncover the enzymology behind an alternative “soluble” route to synthesis of IPs. Inositol tetrakisphosphate 1-kinase 1 (ITPK1)—found in Asgard archaea, social amoeba, plants, and animals—phosphorylates I(3)P1 originating from glucose-6-phosphate, and I(1)P1 generated from sphingolipids, to enable synthesis of IP6. We also found using PAGE mass assay that metabolic blockage by phosphate starvation surprisingly increased IP6 levels in a ITPK1-dependent manner, establishing a route to IP6 controlled by cellular metabolic status, that is not detectable by traditional [3H]-inositol labeling. The presence of ITPK1 in archaeal clades thought to define eukaryogenesis indicates that IPs had functional roles before the appearance of the eukaryote.
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Tipping the scales: Lessons from simple model systems on inositol imbalance in neurological disorders. Eur J Cell Biol 2017; 96:154-163. [PMID: 28153412 DOI: 10.1016/j.ejcb.2017.01.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 01/18/2017] [Accepted: 01/21/2017] [Indexed: 11/20/2022] Open
Abstract
Inositol and inositol-containing compounds have signalling and regulatory roles in many cellular processes, suggesting that inositol imbalance may lead to wide-ranging changes in cellular functions. Indeed, changes in inositol-dependent signalling have been implicated in various diseases and cellular functions such as autophagy, and these changes have often been proposed as therapeutic targets. However, few studies have highlighted the links between inositol depletion and the downstream effects on inositol phosphates and phosphoinositides in disease states. For this research, many advances have employed simple model systems that include the social amoeba D. discoideum and the yeast S. cerevisiae, since these models enable a range of experimental approaches that are not possible in mammalian models. In this review, we discuss recent findings initiated in simple model systems and translated to higher model organisms where the effect of altered inositol, inositol phosphate and phosphoinositide levels impact on bipolar disorder, Alzheimer disease, epilepsy and autophagy.
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Frej AD, Clark J, Le Roy CI, Lilla S, Thomason PA, Otto GP, Churchill G, Insall RH, Claus SP, Hawkins P, Stephens L, Williams RSB. The Inositol-3-Phosphate Synthase Biosynthetic Enzyme Has Distinct Catalytic and Metabolic Roles. Mol Cell Biol 2016; 36:1464-79. [PMID: 26951199 PMCID: PMC4859692 DOI: 10.1128/mcb.00039-16] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 02/19/2016] [Accepted: 03/03/2016] [Indexed: 12/24/2022] Open
Abstract
Inositol levels, maintained by the biosynthetic enzyme inositol-3-phosphate synthase (Ino1), are altered in a range of disorders, including bipolar disorder and Alzheimer's disease. To date, most inositol studies have focused on the molecular and cellular effects of inositol depletion without considering Ino1 levels. Here we employ a simple eukaryote, Dictyostelium discoideum, to demonstrate distinct effects of loss of Ino1 and inositol depletion. We show that loss of Ino1 results in an inositol auxotrophy that can be rescued only partially by exogenous inositol. Removal of inositol supplementation from the ino1(-) mutant resulted in a rapid 56% reduction in inositol levels, triggering the induction of autophagy, reduced cytokinesis, and substrate adhesion. Inositol depletion also caused a dramatic generalized decrease in phosphoinositide levels that was rescued by inositol supplementation. However, loss of Ino1 triggered broad metabolic changes consistent with the induction of a catabolic state that was not rescued by inositol supplementation. These data suggest a metabolic role for Ino1 that is independent of inositol biosynthesis. To characterize this role, an Ino1 binding partner containing SEL1L1 domains (Q54IX5) and having homology to mammalian macromolecular complex adaptor proteins was identified. Our findings therefore identify a new role for Ino1, independent of inositol biosynthesis, with broad effects on cell metabolism.
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Affiliation(s)
- Anna D Frej
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, United Kingdom
| | - Jonathan Clark
- The Babraham Institute, Cambridge, Cambridgeshire, United Kingdom
| | - Caroline I Le Roy
- Department of Food and Nutritional Sciences, The University of Reading, Reading, Berkshire, United Kingdom
| | - Sergio Lilla
- Cancer Research UK Beatson Institute, Bearsden, Glasgow, United Kingdom
| | - Peter A Thomason
- Cancer Research UK Beatson Institute, Bearsden, Glasgow, United Kingdom
| | - Grant P Otto
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, United Kingdom
| | - Grant Churchill
- Department of Pharmacology, University of Oxford, Oxford, Oxfordshire, United Kingdom
| | - Robert H Insall
- Cancer Research UK Beatson Institute, Bearsden, Glasgow, United Kingdom
| | - Sandrine P Claus
- Department of Food and Nutritional Sciences, The University of Reading, Reading, Berkshire, United Kingdom
| | - Phillip Hawkins
- The Babraham Institute, Cambridge, Cambridgeshire, United Kingdom
| | - Len Stephens
- The Babraham Institute, Cambridge, Cambridgeshire, United Kingdom
| | - Robin S B Williams
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, United Kingdom
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Macrae JI, Lopaticki S, Maier AG, Rupasinghe T, Nahid A, Cowman AF, McConville MJ. Plasmodium falciparum is dependent on de novo myo-inositol biosynthesis for assembly of GPI glycolipids and infectivity. Mol Microbiol 2014; 91:762-76. [PMID: 24350823 DOI: 10.1111/mmi.12496] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/15/2013] [Indexed: 12/27/2022]
Abstract
Intra-erythrocytic stages of the malaria parasite, Plasmodium falciparum, are thought to be dependent on de novo synthesis of phosphatidylinositol, as red blood cells (RBC) lack the capacity to synthesize this phospholipid. The myo-inositol headgroup of PI can either be synthesized de novo or scavenged from the RBC. An untargeted metabolite profiling of P. falciparum infected RBC showed that trophozoite and schizont stages accumulate high levels of myo-inositol-3-phosphate, indicating increased de novo biosynthesis of myo-inositol from glucose 6-phosphate. Metabolic labelling studies with (13) C-U-glucose in the presence and absence of exogenous inositol confirmed that de novo myo-inositol synthesis occurs in parallel with myo-inositol salvage pathways. Unexpectedly, while both endogenous and scavenged myo-inositol was used to synthesize bulk PI, only de novo-synthesized myo-inositol was incorporated into GPI glycolipids. Moreover, gene disruption studies suggested that the INO1 gene, encoding myo-inositol 3-phosphate synthase, is essential in asexual parasite stages. Together these findings suggest that P. falciparum asexual stages are critically dependent on de novo myo-inositol biosynthesis for assembly of a sub-pool of PI species and GPI biosynthesis. These findings highlight unexpected complexity in phospholipid biosynthesis in P. falciparum and a lack of redundancy in some nutrient salvage versus endogenous biosynthesis pathways.
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Affiliation(s)
- James I Macrae
- Department of Biochemistry and Molecular Biology, Bio21 Institute of Molecular Science and Biotechnology, 30 Flemington Road, Melbourne, Vic., 3010, Australia
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Kallert DM, Ponader S, Adelt S, Kaese P, Geyer R, Haas W, El-Matbouli M. Analysis of rainbow trout Oncorhynchus mykiss epidermal mucus and evaluation of semiochemical activity for polar filament discharge in Myxobolus cerebralis actinospores. JOURNAL OF FISH BIOLOGY 2010; 77:1579-1598. [PMID: 21078020 DOI: 10.1111/j.1095-8649.2010.02785.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
As myxozoan actinospores are stimulated by fish epidermal mucus to attach to their hosts via extrusion of filaments from specialized organelles, the polar capsules, mucus components were tested for discharge triggering activity on Myxobolus cerebralis actinospores. Using various methodological approaches, a selective exclusion of candidate substances based on experimental outcome is provided and the physiochemical traits of the putative agents are explored to create a basis for the isolation of the host recognition chemostimuli. Activity was detected in compounds that can be characterized as small molecular, amphiphilic to slightly hydrophobic organic substances. They were separable by chromatographic methods using reversed phase C18 supports. An active fraction was isolated by solid phase extraction comprising at least nine UV-detectable constituents as shown by thin-layer chromatography. By means of biochemical fractionation and analysis of host fish mucus, non-volatile inorganic electrolytes, all volatiles, free L-amino acids, glycoproteins, bound and free hexoses, sialic acids, glycans, proteins, urea, amines and inositols were shown not to trigger polar filament discharge. The results contribute to the identification of the attachment host cues and enable a more focused laboratory activation of myxozoan actinospores.
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Affiliation(s)
- D M Kallert
- Fish Medicine and Livestock Management, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Veterinärplatz 1, 1210 Vienna, Austria
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King J, Keim M, Teo R, Weening KE, Kapur M, McQuillan K, Ryves J, Rogers B, Dalton E, Williams RSB, Harwood AJ. Genetic control of lithium sensitivity and regulation of inositol biosynthetic genes. PLoS One 2010; 5:e11151. [PMID: 20567601 PMCID: PMC2887444 DOI: 10.1371/journal.pone.0011151] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Accepted: 03/30/2010] [Indexed: 12/12/2022] Open
Abstract
Lithium (Li(+)) is a common treatment for bipolar mood disorder, a major psychiatric illness with a lifetime prevalence of more than 1%. Risk of bipolar disorder is heavily influenced by genetic predisposition, but is a complex genetic trait and, to date, genetic studies have provided little insight into its molecular origins. An alternative approach is to investigate the genetics of Li(+) sensitivity. Using the social amoeba Dictyostelium, we previously identified prolyl oligopeptidase (PO) as a modulator of Li(+) sensitivity. In a link to the clinic, PO enzyme activity is altered in bipolar disorder patients. Further studies demonstrated that PO is a negative regulator of inositol(1,4,5)trisphosphate (IP(3)) synthesis, a Li(+) sensitive intracellular signal. However, it was unclear how PO could influence either Li(+) sensitivity or risk of bipolar disorder. Here we show that in both Dictyostelium and cultured human cells PO acts via Multiple Inositol Polyphosphate Phosphatase (Mipp1) to control gene expression. This reveals a novel, gene regulatory network that modulates inositol metabolism and Li(+) sensitivity. Among its targets is the inositol monophosphatase gene IMPA2, which has also been associated with risk of bipolar disorder in some family studies, and our observations offer a cellular signalling pathway in which PO activity and IMPA2 gene expression converge.
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Affiliation(s)
- Jason King
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Melanie Keim
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Regina Teo
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Karin E. Weening
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Mridu Kapur
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Karina McQuillan
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Jonathan Ryves
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Ben Rogers
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Emma Dalton
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Robin S. B. Williams
- School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey, United Kingdom
| | - Adrian J. Harwood
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
- * E-mail:
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Timmermans MJTN, Roelofs D, Nota B, Ylstra B, Holmstrup M. Sugar sweet springtails: on the transcriptional response of Folsomia candida (Collembola) to desiccation stress. INSECT MOLECULAR BIOLOGY 2009; 18:737-46. [PMID: 19788701 DOI: 10.1111/j.1365-2583.2009.00916.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Several species of Collembola survive stressful desiccating conditions by absorbing water vapour from the environment. To obtain insight into the transcriptomic responses underlying this 'water vapour absorption' mechanism we subjected Folsomia candida (Collembola) to transcriptome profiling. We show that ecologically relevant desiccation stress leads to strong time-dependent transcriptomic changes. Exposure of F. candida to 98.2% relative humidity over an interval of 174 h resulted in a high number of gene transcripts being differentially expressed (up to 41%; P-value < 0.05). Additional Gene Ontology analyses suggest that carbohydrate transport, sugar catabolism and cuticle maintenance are biological processes involved in combating desiccation. However, many additional pathways seem to be affected; additional experiments are needed to elucidate which responses are primarily linked to desiccation resistance.
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Affiliation(s)
- M J T N Timmermans
- Department of Animal Ecology, VU University Amsterdam, Amsterdam, the Netherlands
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Cho J, King JS, Qian X, Harwood AJ, Shears SB. Dephosphorylation of 2,3-bisphosphoglycerate by MIPP expands the regulatory capacity of the Rapoport-Luebering glycolytic shunt. Proc Natl Acad Sci U S A 2008; 105:5998-6003. [PMID: 18413611 PMCID: PMC2329705 DOI: 10.1073/pnas.0710980105] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2007] [Indexed: 11/18/2022] Open
Abstract
The Rapoport-Luebering glycolytic bypass comprises evolutionarily conserved reactions that generate and dephosphorylate 2,3-bisphosphoglycerate (2,3-BPG). For >30 years, these reactions have been considered the responsibility of a single enzyme, the 2,3-BPG synthase/2-phosphatase (BPGM). Here, we show that Dictyostelium, birds, and mammals contain an additional 2,3-BPG phosphatase that, unlike BPGM, removes the 3-phosphate. This discovery reveals that the glycolytic pathway can bypass the formation of 3-phosphoglycerate, which is a precursor for serine biosynthesis and an activator of AMP-activated protein kinase. Our 2,3-BPG phosphatase activity is encoded by the previously identified gene for multiple inositol polyphosphate phosphatase (MIPP1), which we now show to have dual substrate specificity. By genetically manipulating Mipp1 expression in Dictyostelium, we demonstrated that this enzyme provides physiologically relevant regulation of cellular 2,3-BPG content. Mammalian erythrocytes possess the highest content of 2,3-BPG, which controls oxygen binding to hemoglobin. We determined that total MIPP1 activity in erythrocytes at 37 degrees C is 0.6 mmol 2,3-BPG hydrolyzed per liter of cells per h, matching previously published estimates of the phosphatase activity of BPGM. MIPP1 is active at 4 degrees C, revealing a clinically significant contribution to 2,3-BPG loss during the storage of erythrocytes for transfusion. Hydrolysis of 2,3-BPG by human MIPP1 is sensitive to physiologic alkalosis; activity decreases 50% when pH rises from 7.0 to 7.4. This phenomenon provides a homeostatic mechanism for elevating 2,3-BPG levels, thereby enhancing oxygen release to tissues. Our data indicate greater biological significance of the Rapoport-Luebering shunt than previously considered.
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Affiliation(s)
- Jaiesoon Cho
- *Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Social Services, P.O. Box 12233, Research Triangle Park, NC 27709; and
| | - Jason S. King
- Cardiff School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3US, United Kingdom
| | - Xun Qian
- *Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Social Services, P.O. Box 12233, Research Triangle Park, NC 27709; and
| | - Adrian J. Harwood
- Cardiff School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3US, United Kingdom
| | - Stephen B. Shears
- *Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Social Services, P.O. Box 12233, Research Triangle Park, NC 27709; and
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Phagocytosis and host-pathogen interactions in Dictyostelium with a look at macrophages. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2008; 271:253-300. [PMID: 19081545 DOI: 10.1016/s1937-6448(08)01206-9] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Research into phagocytosis and host-pathogen interactions in the lower eukaryote Dictyostelium discoideum has flourished in recent years. This chapter presents a glimpse of where this research stands, with emphasis on the cell biology of the phagocytic process and on the wealth of molecular genetic data that have been gathered. The basic mechanistic machinery and most of the underlying genes appear to be evolutionarily conserved, reflecting the fact that phagocytosis arose as an efficient way to ingest food in single protozoan cells devoid of a rigid cell wall. In spite of some differences, the signal transduction pathways regulating phagosome biogenesis are also emerging as ultimately similar between Dictyostelium and macrophages. Both cell types are hosts for many pathogenic invasive bacteria, which exploit phagocytosis to grow intracellularly. We present an overwiew, based on the analysis of mutants, on how Dictyostelium contributes as a genetic model system to decipher the complexity of host-pathogen interactions.
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