1
|
Boland AW, Gas-Pascual E, van der Wel H, Kim HW, West CM. Synergy between a cytoplasmic vWFA/VIT protein and a WD40-repeat F-box protein controls development in Dictyostelium. Front Cell Dev Biol 2023; 11:1259844. [PMID: 37779900 PMCID: PMC10539598 DOI: 10.3389/fcell.2023.1259844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Accepted: 08/24/2023] [Indexed: 10/03/2023] Open
Abstract
Like most eukaryotes, the pre-metazoan social amoeba Dictyostelium depends on the SCF (Skp1/cullin-1/F-box protein) family of E3 ubiquitin ligases to regulate its proteome. In Dictyostelium, starvation induces a transition from unicellular feeding to a multicellular slug that responds to external signals to culminate into a fruiting body containing terminally differentiated stalk and spore cells. These transitions are subject to regulation by F-box proteins and O2-dependent posttranslational modifications of Skp1. Here we examine in greater depth the essential role of FbxwD and Vwa1, an intracellular vault protein inter-alpha-trypsin (VIT) and von Willebrand factor-A (vWFA) domain containing protein that was found in the FbxwD interactome by co-immunoprecipitation. Reciprocal co-IPs using gene-tagged strains confirmed the interaction and similar changes in protein levels during multicellular development suggested co-functioning. FbxwD overexpression and proteasome inhibitors did not affect Vwa1 levels suggesting a non-substrate relationship. Forced FbxwD overexpression in slug tip cells where it is normally enriched interfered with terminal cell differentiation by a mechanism that depended on its F-box and RING domains, and on Vwa1 expression itself. Whereas vwa1-disruption alone did not affect development, overexpression of either of its three conserved domains arrested development but the effect depended on Vwa1 expression. Based on structure predictions, we propose that the Vwa1 domains exert their negative effect by artificially activating Vwa1 from an autoinhibited state, which in turn imbalances its synergistic function with FbxwD. Autoinhibition or homodimerization might be relevant to the poorly understood tumor suppressor role of the evolutionarily related VWA5A/BCSC-1 in humans.
Collapse
Affiliation(s)
- Andrew W. Boland
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States
| | - Elisabet Gas-Pascual
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States
| | - Hanke van der Wel
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
| | - Hyun W. Kim
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
| | - Christopher M. West
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States
| |
Collapse
|
2
|
van der Wel H, Garcia AM, Gas-Pascual E, Willis MM, Kim HW, Bandini G, Gaye MM, Costello CE, Samuelson J, West CM. Spindly is a nucleocytosolic O-fucosyltransferase in Dictyostelium and related proteins are widespread in protists and bacteria. Glycobiology 2023; 33:225-244. [PMID: 36250576 PMCID: PMC10114647 DOI: 10.1093/glycob/cwac071] [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: 08/21/2022] [Revised: 10/09/2022] [Accepted: 10/13/2022] [Indexed: 11/15/2022] Open
Abstract
O-GlcNAcylation is a prominent modification of nuclear and cytoplasmic proteins in animals and plants and is mediated by a single O-GlcNAc transferase (OGT). Spindly (Spy), a paralog of OGT first discovered in higher plants, has an ortholog in the apicomplexan parasite Toxoplasma gondii, and both enzymes are now recognized as O-fucosyltransferases (OFTs). Here we investigate the evolution of spy-like genes and experimentally confirm OFT activity in the social amoeba Dictyostelium-a protist that is more related to fungi and metazoa. Immunofluorescence probing with the fucose-specific Aleuria aurantia lectin (AAL) and biochemical cell fractionation combined with western blotting suggested the occurrence of nucleocytoplasmic fucosylation. The absence of reactivity in mutants deleted in spy or gmd (unable to synthesize GDP-Fuc) suggested monofucosylation mediated by Spy. Genetic ablation of the modE locus, previously predicted to encode a GDP-fucose transporter, confirmed its necessity for fucosylation in the secretory pathway but not for the nucleocytoplasmic proteins. Affinity capture of these proteins combined with mass spectrometry confirmed monofucosylation of Ser and Thr residues of several known nucleocytoplasmic proteins. As in Toxoplasma, the Spy OFT was required for optimal proliferation of Dictyostelium under laboratory conditions. These findings support a new phylogenetic analysis of OGT and OFT evolution that indicates their occurrence in the last eukaryotic common ancestor but mostly complementary presence in its eukaryotic descendants with the notable exception that both occur in red algae and plants. Their generally exclusive expression, high degree of conservation, and shared monoglycosylation targets suggest overlapping roles in physiological regulation.
Collapse
Affiliation(s)
- Hanke van der Wel
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Ana Maria Garcia
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Obstetrics and Gynecology (OBGYN), 1951 SW 172nd Ave, Hollywood, FL 33029, USA
| | - Elisabet Gas-Pascual
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Macy M Willis
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Hyun W Kim
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Giulia Bandini
- Department of Molecular and Cell Biology, Boston University Henry Goldman School of Dental Medicine, Boston, MA 02118, USA
- Clarivate Analytics (UK) Ltd., 70 St. Mary Axe, London, EC3A 8BE
| | - Maissa Mareme Gaye
- Department of Biochemistry, Center for Biomedical Mass Spectrometry, Boston University School of Medicine, Boston, MA 02118, USA
- Chemistry Technology Center, Waters Corporation, Milford, MA 01757, USA
| | - Catherine E Costello
- Department of Biochemistry, Center for Biomedical Mass Spectrometry, Boston University School of Medicine, Boston, MA 02118, USA
| | - John Samuelson
- Department of Molecular and Cell Biology, Boston University Henry Goldman School of Dental Medicine, Boston, MA 02118, USA
| | - Christopher M West
- Department of Biochemistry and Molecular Biology, Center for Tropical and Emerging Global Diseases, Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| |
Collapse
|
3
|
Ghosh R, Biswas P, Das M, Pal S, Dam S. In silico analysis of a Skp1 protein homolog from the human pathogen E. histolytica. J Parasit Dis 2022; 46:998-1010. [PMID: 36457763 PMCID: PMC9606183 DOI: 10.1007/s12639-022-01523-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 07/03/2022] [Indexed: 10/16/2022] Open
Abstract
SCF complex consisting of Skp1, Cullins, F-box proteins, is the largest family of E3 ubiquitin ligases that promotes ubiquitination of many substrate proteins and controls numerous cellular processes. Skp1 is an adapter protein that binds directly to the F-box proteins. In this study, we have presented the first comprehensive analysis of the presence of peptides or proteins in the human pathogen Entamoeba histolytica having homology to Skp1protein. The occurrence of other protein components of the SCF complex has been identified from protein-protein interaction network of EhSkp1A. Studying the role of Skp1protein in this pathogen would help to understand its unique chromosome segregation and cell division which are different from higher eukaryotes. Further, owing to the development of resistance over several drugs that are currently available, there is a growing need for a novel drug against E. histolytica. Proteins from ubiquitin-proteasome pathway have received attention as potential drug targets in other parasites. We have identified four homologs of Skp1 protein in E. histolytica strain HM-1: IMSS. Molecular docking study between EhSkp1A and an F-box/WD domain-containing protein (EhFBXW) shows that the F-box domain in the N-terminal region of EhFBXW interacts with EhSkp1A. Therefore, the results of the present study shall provide a stable foundation for further research on the cell cycle regulation of E. histolytica and this will help researchers to develop new drugs against this parasite. Supplementary Information The online version contains supplementary material available at 10.1007/s12639-022-01523-0.
Collapse
Affiliation(s)
- Raktim Ghosh
- Department of Microbiology, The University of Burdwan, Burdwan, West Bengal 713104 India
| | - Pinaki Biswas
- Department of Microbiology, The University of Burdwan, Burdwan, West Bengal 713104 India
| | - Moubonny Das
- Department of Microbiology, The University of Burdwan, Burdwan, West Bengal 713104 India
| | - Suchetana Pal
- Department of Microbiology, The University of Burdwan, Burdwan, West Bengal 713104 India
| | - Somasri Dam
- Department of Microbiology, The University of Burdwan, Burdwan, West Bengal 713104 India
| |
Collapse
|
4
|
Boland AW, Gas-Pascual E, Nottingham BL, van der Wel H, Daniel NG, Sheikh MO, Schafer CM, West CM. Oxygen-dependent regulation of E3(SCF)ubiquitin ligases and a Skp1-associated JmjD6 homolog in development of the social amoeba Dictyostelium. J Biol Chem 2022; 298:102305. [PMID: 35933019 PMCID: PMC9485057 DOI: 10.1016/j.jbc.2022.102305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 07/10/2022] [Accepted: 07/11/2022] [Indexed: 11/01/2022] Open
Abstract
E3-SCF (Skp1/cullin-1/F-box protein) polyubiquitin ligases activate the proteasomal degradation of over a thousand proteins, but the evolutionary diversification of the F-box protein (FBP) family of substrate receptor subunits has challenged their elucidation in protists. Here, we expand the FBP candidate list in the social amoeba Dictyostelium and show that the Skp1 interactome is highly remodeled as cells transition from growth to multicellular development. Importantly, a subset of candidate FBPs was less represented when the posttranslational hydroxylation and glycosylation of Skp1 was abrogated by deletion of the O2-sensing Skp1 prolyl hydroxylase PhyA. A role for this Skp1 modification for SCF activity was indicated by partial rescue of development, which normally depends on high O2 and PhyA, of phyA-KO cells by proteasomal inhibitors. Further examination of two FBPs, FbxwD and the Jumonji C protein JcdI, suggested that Skp1 was substituted by other factors in phyA-KO cells. Although a double-KO of jcdI and its paralog jcdH did not affect development, overexpression of JcdI increased its sensitivity to O2. JcdI, a nonheme dioxygenase shown to have physiological O2 dependence, is conserved across protists with its F-box and other domains, and is related to the human oncogene JmjD6. Sensitization of JcdI-overexpression cells to O2 depended on its dioxygenase activity and other domains, but not its F-box, which may however be the mediator of its reduced levels in WT relative to Skp1 modification mutant cells. The findings suggest that activation of JcdI by O2 is tempered by homeostatic downregulation via PhyA and association with Skp1.
Collapse
Affiliation(s)
- Andrew W Boland
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, Georgia, USA; Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Elisabet Gas-Pascual
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, Georgia, USA; Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA; Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
| | - Braxton L Nottingham
- Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Hanke van der Wel
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, Georgia, USA; Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Nitin G Daniel
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - M Osman Sheikh
- Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Christopher M Schafer
- Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Christopher M West
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, Georgia, USA; Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA; Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA; Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.
| |
Collapse
|
5
|
Kim WD, Mathavarajah S, Huber RJ. The Cellular and Developmental Roles of Cullins, Neddylation, and the COP9 Signalosome in Dictyostelium discoideum. Front Physiol 2022; 13:827435. [PMID: 35586714 PMCID: PMC9108976 DOI: 10.3389/fphys.2022.827435] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 02/03/2022] [Indexed: 12/02/2022] Open
Abstract
Cullins (CULs) are a core component of cullin-RING E3 ubiquitin ligases (CRLs), which regulate the degradation, function, and subcellular trafficking of proteins. CULs are post-translationally regulated through neddylation, a process that conjugates the ubiquitin-like modifier protein neural precursor cell expressed developmentally downregulated protein 8 (NEDD8) to target cullins, as well as non-cullin proteins. Counteracting neddylation is the deneddylase, COP9 signalosome (CSN), which removes NEDD8 from target proteins. Recent comparative genomics studies revealed that CRLs and the CSN are highly conserved in Amoebozoa. A well-studied representative of Amoebozoa, the social amoeba Dictyostelium discoideum, has been used for close to 100 years as a model organism for studying conserved cellular and developmental processes owing to its unique life cycle comprised of unicellular and multicellular phases. The organism is also recognized as an exceptional model system for studying cellular processes impacted by human diseases, including but not limited to, cancer and neurodegeneration. Recent work shows that the neddylation inhibitor, MLN4924 (Pevonedistat), inhibits growth and multicellular development in D. discoideum, which supports previous work that revealed the cullin interactome in D. discoideum and the roles of cullins and the CSN in regulating cellular and developmental processes during the D. discoideum life cycle. Here, we review the roles of cullins, neddylation, and the CSN in D. discoideum to guide future work on using this biomedical model system to further explore the evolutionarily conserved functions of cullins and neddylation.
Collapse
Affiliation(s)
- William D. Kim
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON, Canada
| | | | - Robert J. Huber
- Department of Biology, Trent University, Peterborough, ON, Canada
| |
Collapse
|
6
|
The Extracellular Milieu of Toxoplasma's Lytic Cycle Drives Lab Adaptation, Primarily by Transcriptional Reprogramming. mSystems 2021; 6:e0119621. [PMID: 34874774 PMCID: PMC8651083 DOI: 10.1128/msystems.01196-21] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Evolve and resequencing (E&R) was applied to lab adaptation of Toxoplasma gondii for over 1,500 generations with the goal of mapping host-independent in vitro virulence traits. Phenotypic assessments of steps across the lytic cycle revealed that only traits needed in the extracellular milieu evolved. Nonsynonymous single-nucleotide polymorphisms (SNPs) in only one gene, a P4 flippase, fixated across two different evolving populations, whereas dramatic changes in the transcriptional signature of extracellular parasites were identified. Newly developed computational tools correlated phenotypes evolving at different rates with specific transcriptomic changes. A set of 300 phenotype-associated genes was mapped, of which nearly 50% is annotated as hypothetical. Validation of a select number of genes by knockouts confirmed their role in lab adaptation and highlights novel mechanisms underlying in vitro virulence traits. Further analyses of differentially expressed genes revealed the development of a “pro-tachyzoite” profile as well as the upregulation of the fatty acid biosynthesis (FASII) pathway. The latter aligned with the P4 flippase SNP and aligned with a low abundance of medium-chain fatty acids at low passage, indicating this is a limiting factor in extracellular parasites. In addition, partial overlap with the bradyzoite differentiation transcriptome in extracellular parasites indicated that stress pathways are involved in both situations. This was reflected in the partial overlap between the assembled ApiAP2 and Myb transcription factor network underlying the adapting extracellular state with the bradyzoite differentiation program. Overall, E&R is a new genomic tool successfully applied to map the development of polygenic traits underlying in vitro virulence of T. gondii. IMPORTANCE It has been well established that prolonged in vitro cultivation of Toxoplasma gondii augments progression of the lytic cycle. This lab adaptation results in increased capacities to divide, migrate, and survive outside a host cell, all of which are considered host-independent virulence factors. However, the mechanistic basis underlying these enhanced virulence features is unknown. Here, E&R was utilized to empirically characterize the phenotypic, genomic, and transcriptomic changes in the non-lab-adapted strain, GT1, during 2.5 years of lab adaptation. This identified the shutdown of stage differentiation and upregulation of lipid biosynthetic pathways as the key processes being modulated. Furthermore, lab adaptation was primarily driven by transcriptional reprogramming, which rejected the starting hypothesis that genetic mutations would drive lab adaptation. Overall, the work empirically shows that lab adaptation augments T. gondii’s in vitro virulence by transcriptional reprogramming and that E&R is a powerful new tool to map multigenic traits.
Collapse
|
7
|
Rogals MJ, Yang JY, Williams RV, Moremen KW, Amster IJ, Prestegard JH. Sparse isotope labeling for nuclear magnetic resonance (NMR) of glycoproteins using 13C-glucose. Glycobiology 2021; 31:425-435. [PMID: 32902634 PMCID: PMC8091466 DOI: 10.1093/glycob/cwaa071] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 07/22/2020] [Accepted: 07/24/2020] [Indexed: 01/02/2023] Open
Abstract
Preparation of samples for nuclear magnetic resonance (NMR) characterization of larger proteins requires enrichment with less abundant, NMR-active, isotopes such as 13C and 15N. This is routine for proteins that can be expressed in bacterial culture where low-cost isotopically enriched metabolic substrates can be used. However, it can be expensive for glycosylated proteins expressed in mammalian culture where more costly isotopically enriched amino acids are usually used. We describe a simple, relatively inexpensive procedure in which standard commercial media is supplemented with 13C-enriched glucose to achieve labeling of all glycans plus all alanines of the N-terminal domain of the highly glycosylated protein, CEACAM1. We demonstrate an ability to detect partially occupied N-glycan sites, sites less susceptible to processing by an endoglycosidase, and some unexpected truncation of the amino acid sequence. The labeling of both the protein (through alanines) and the glycans in a single culture requiring no additional technical expertise past standard mammalian expression requirements is anticipated to have several applications, including structural and functional screening of the many glycosylated proteins important to human health.
Collapse
Affiliation(s)
- Monique J Rogals
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd., Athens, GA 30602, USA
| | - Jeong-Yeh Yang
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd., Athens, GA 30602, USA
| | - Robert V Williams
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd., Athens, GA 30602, USA
- Department of Chemistry
| | - Kelley W Moremen
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd., Athens, GA 30602, USA
- Department of Biochemistry and Molecular Biology
| | | | - James H Prestegard
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd., Athens, GA 30602, USA
- Department of Chemistry
- Department of Biochemistry and Molecular Biology
| |
Collapse
|
8
|
Huber RJ, Kim WD, Mathavarajah S. Inhibiting Neddylation with MLN4924 Suppresses Growth and Delays Multicellular Development in Dictyostelium discoideum. Biomolecules 2021; 11:482. [PMID: 33807046 PMCID: PMC8005062 DOI: 10.3390/biom11030482] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 03/17/2021] [Accepted: 03/19/2021] [Indexed: 12/18/2022] Open
Abstract
Neddylation is a post-translational modification that is essential for a variety of cellular processes and is linked to many human diseases including cancer, neurodegeneration, and autoimmune disorders. Neddylation involves the conjugation of the ubiquitin-like modifier neural precursor cell expressed developmentally downregulated protein 8 (NEDD8) to target proteins, and has been studied extensively in various eukaryotes including fungi, plants, and metazoans. Here, we examine the biological processes influenced by neddylation in the social amoeba, Dictyostelium discoideum, using a well-established inhibitor of neddylation, MLN4924 (pevonedistat). NEDD8, and the target of MLN4924 inhibition, NEDD8-activating enzyme E1 (NAE1), are highly conserved in D. discoideum (Nedd8 and Nae1, respectively). Treatment of D. discoideum cells with MLN4924 increased the amount of free Nedd8, suggesting that MLN4924 inhibited neddylation. During growth, MLN4924 suppressed cell proliferation and folic acid-mediated chemotaxis. During multicellular development, MLN4924 inhibited cyclic adenosine monophosphate (cAMP)-mediated chemotaxis, delayed aggregation, and suppressed fruiting body formation. Together, these findings indicate that neddylation plays an important role in regulating cellular and developmental events during the D. discoideum life cycle and that this organism can be used as a model system to better understand the essential roles of neddylation in eukaryotes, and consequently, its involvement in human disease.
Collapse
Affiliation(s)
- Robert J. Huber
- Department of Biology, Trent University, Peterborough, ON K9L 0G2, Canada
| | - William D. Kim
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON K9L 0G2, Canada;
| | | |
Collapse
|
9
|
Mathavarajah S, VanIderstine C, Dellaire G, Huber RJ. Cancer and the breakdown of multicellularity: What Dictyostelium discoideum, a social amoeba, can teach us. Bioessays 2021; 43:e2000156. [PMID: 33448043 DOI: 10.1002/bies.202000156] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 12/11/2020] [Accepted: 12/17/2020] [Indexed: 01/01/2023]
Abstract
Ancient pathways promoting unicellularity and multicellularity are associated with cancer, the former being pro-oncogenic and the latter acting to suppress oncogenesis. However, there are only a limited number of non-vertebrate models for studying these pathways. Here, we review Dictyostelium discoideum and describe how it can be used to understand these gene networks. D. discoideum has a unicellular and multicellular life cycle, making it possible to study orthologs of cancer-associated genes in both phases. During development, differentiated amoebae form a fruiting body composed of a mass of spores that are supported atop a stalk. A portion of the cells sacrifice themselves to become non-reproductive stalk cells. Cheating disrupts the principles of multicellularity, as cheater cells alter their cell fate to preferentially become spores. Importantly, D. discoideum has gene networks and several strategies for maintaining multicellularity. Therefore, D. discoideum can help us better understand how conserved genes and pathways involved in multicellularity also influence cancer development, potentially identifying new therapeutic avenues.
Collapse
Affiliation(s)
- Sabateeshan Mathavarajah
- Department of Pathology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Carter VanIderstine
- Department of Pathology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Graham Dellaire
- Department of Pathology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.,Department of Biochemistry and Molecular Biology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Robert J Huber
- Department of Biology, Trent University, Peterborough, Ontario, Canada
| |
Collapse
|
10
|
West CM, Malzl D, Hykollari A, Wilson IBH. Glycomics, Glycoproteomics, and Glycogenomics: An Inter-Taxa Evolutionary Perspective. Mol Cell Proteomics 2021; 20:100024. [PMID: 32994314 PMCID: PMC8724618 DOI: 10.1074/mcp.r120.002263] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/21/2020] [Accepted: 09/28/2020] [Indexed: 12/23/2022] Open
Abstract
Glycosylation is a highly diverse set of co- and posttranslational modifications of proteins. For mammalian glycoproteins, glycosylation is often site-, tissue-, and species-specific and diversified by microheterogeneity. Multitudinous biochemical, cellular, physiological, and organismic effects of their glycans have been revealed, either intrinsic to the carrier proteins or mediated by endogenous reader proteins with carbohydrate recognition domains. Furthermore, glycans frequently form the first line of access by or defense from foreign invaders, and new roles for nucleocytoplasmic glycosylation are blossoming. We now know enough to conclude that the same general principles apply in invertebrate animals and unicellular eukaryotes-different branches of which spawned the plants or fungi and animals. The two major driving forces for exploring the glycomes of invertebrates and protists are (i) to understand the biochemical basis of glycan-driven biology in these organisms, especially of pathogens, and (ii) to uncover the evolutionary relationships between glycans, their biosynthetic enzyme genes, and biological functions for new glycobiological insights. With an emphasis on emerging areas of protist glycobiology, here we offer an overview of glycan diversity and evolution, to promote future access to this treasure trove of glycobiological processes.
Collapse
Affiliation(s)
- Christopher M West
- Department of Biochemistry & Molecular Biology, Center for Tropical and Emerging Global Diseases, Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA.
| | - Daniel Malzl
- Department für Chemie, Universität für Bodenkultur, Wien, Austria
| | - Alba Hykollari
- Department für Chemie, Universität für Bodenkultur, Wien, Austria; VetCore Facility for Research/Proteomics Unit, Veterinärmedizinische Universität, Vienna, Austria
| | - Iain B H Wilson
- Department für Chemie, Universität für Bodenkultur, Wien, Austria
| |
Collapse
|
11
|
Liu T, Abboud MI, Chowdhury R, Tumber A, Hardy AP, Lippl K, Lohans CT, Pires E, Wickens J, McDonough MA, West CM, Schofield CJ. Biochemical and biophysical analyses of hypoxia sensing prolyl hydroxylases from Dictyostelium discoideum and Toxoplasma gondii. J Biol Chem 2020; 295:16545-16561. [PMID: 32934009 PMCID: PMC7864055 DOI: 10.1074/jbc.ra120.013998] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 08/14/2020] [Indexed: 12/30/2022] Open
Abstract
In animals, the response to chronic hypoxia is mediated by prolyl hydroxylases (PHDs) that regulate the levels of hypoxia-inducible transcription factor α (HIFα). PHD homologues exist in other types of eukaryotes and prokaryotes where they act on non HIF substrates. To gain insight into the factors underlying different PHD substrates and properties, we carried out biochemical and biophysical studies on PHD homologues from the cellular slime mold, Dictyostelium discoideum, and the protozoan parasite, Toxoplasma gondii, both lacking HIF. The respective prolyl-hydroxylases (DdPhyA and TgPhyA) catalyze prolyl-hydroxylation of S-phase kinase-associated protein 1 (Skp1), a reaction enabling adaptation to different dioxygen availability. Assays with full-length Skp1 substrates reveal substantial differences in the kinetic properties of DdPhyA and TgPhyA, both with respect to each other and compared with human PHD2; consistent with cellular studies, TgPhyA is more active at low dioxygen concentrations than DdPhyA. TgSkp1 is a DdPhyA substrate and DdSkp1 is a TgPhyA substrate. No cross-reactivity was detected between DdPhyA/TgPhyA substrates and human PHD2. The human Skp1 E147P variant is a DdPhyA and TgPhyA substrate, suggesting some retention of ancestral interactions. Crystallographic analysis of DdPhyA enables comparisons with homologues from humans, Trichoplax adhaerens, and prokaryotes, informing on differences in mobile elements involved in substrate binding and catalysis. In DdPhyA, two mobile loops that enclose substrates in the PHDs are conserved, but the C-terminal helix of the PHDs is strikingly absent. The combined results support the proposal that PHD homologues have evolved kinetic and structural features suited to their specific sensing roles.
Collapse
Affiliation(s)
- Tongri Liu
- Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom
| | - Martine I Abboud
- Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom
| | | | - Anthony Tumber
- Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom
| | - Adam P Hardy
- Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom
| | - Kerstin Lippl
- Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom
| | | | - Elisabete Pires
- Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom
| | - James Wickens
- Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom
| | | | - Christopher M West
- Department of Biochemistry and Molecular Biology, Complex Carbohydrate Research Center, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
| | | |
Collapse
|
12
|
Mandalasi M, Kim HW, Thieker D, Sheikh MO, Gas-Pascual E, Rahman K, Zhao P, Daniel NG, van der Wel H, Ichikawa HT, Glushka JN, Wells L, Woods RJ, Wood ZA, West CM. A terminal α3-galactose modification regulates an E3 ubiquitin ligase subunit in Toxoplasma gondii. J Biol Chem 2020; 295:9223-9243. [PMID: 32414843 PMCID: PMC7335778 DOI: 10.1074/jbc.ra120.013792] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 05/14/2020] [Indexed: 12/29/2022] Open
Abstract
Skp1, a subunit of E3 Skp1/Cullin-1/F-box protein ubiquitin ligases, is modified by a prolyl hydroxylase that mediates O2 regulation of the social amoeba Dictyostelium and the parasite Toxoplasma gondii The full effect of hydroxylation requires modification of the hydroxyproline by a pentasaccharide that, in Dictyostelium, influences Skp1 structure to favor assembly of Skp1/F-box protein subcomplexes. In Toxoplasma, the presence of a contrasting penultimate sugar assembled by a different glycosyltransferase enables testing of the conformational control model. To define the final sugar and its linkage, here we identified the glycosyltransferase that completes the glycan and found that it is closely related to glycogenin, an enzyme that may prime glycogen synthesis in yeast and animals. However, the Toxoplasma enzyme catalyzes formation of a Galα1,3Glcα linkage rather than the Glcα1,4Glcα linkage formed by glycogenin. Kinetic and crystallographic experiments showed that the glycosyltransferase Gat1 is specific for Skp1 in Toxoplasma and also in another protist, the crop pathogen Pythium ultimum The fifth sugar is important for glycan function as indicated by the slow-growth phenotype of gat1Δ parasites. Computational analyses indicated that, despite the sequence difference, the Toxoplasma glycan still assumes an ordered conformation that controls Skp1 structure and revealed the importance of nonpolar packing interactions of the fifth sugar. The substitution of glycosyltransferases in Toxoplasma and Pythium by an unrelated bifunctional enzyme that assembles a distinct but structurally compatible glycan in Dictyostelium is a remarkable case of convergent evolution, which emphasizes the importance of the terminal α-galactose and establishes the phylogenetic breadth of Skp1 glycoregulation.
Collapse
Affiliation(s)
- Msano Mandalasi
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA; Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
| | - Hyun W Kim
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - David Thieker
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - M Osman Sheikh
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Elisabet Gas-Pascual
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA; Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
| | - Kazi Rahman
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Peng Zhao
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Nitin G Daniel
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Hanke van der Wel
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - H Travis Ichikawa
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - John N Glushka
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Lance Wells
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA; Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Robert J Woods
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA; Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Zachary A Wood
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Christopher M West
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA; Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA; Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA.
| |
Collapse
|
13
|
Abd-Hamid NA, Ahmad-Fauzi MI, Zainal Z, Ismail I. Diverse and dynamic roles of F-box proteins in plant biology. PLANTA 2020; 251:68. [PMID: 32072251 DOI: 10.1007/s00425-020-03356-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 02/05/2020] [Indexed: 05/23/2023]
Abstract
The SCF complex is a widely studied multi-subunit ring E3 ubiquitin ligase that tags targeted proteins with ubiquitin for protein degradation by the ubiquitin 26S-proteasome system (UPS). The UPS is an important system that generally keeps cellular events tightly regulated by purging misfolded or damaged proteins and selectively degrading important regulatory proteins. The specificity of this post-translational regulation is controlled by F-box proteins (FBPs) via selective recognition of a protein-protein interaction motif at the C-terminal domain. Hence, FBPs are pivotal proteins in determining the plant response in multiple scenarios. It is not surprising that the FBP family is one of the largest protein families in the plant kingdom. In this review, the roles of FBPs, specifically in plants, are compiled to provide insights into their involvement in secondary metabolites, plant stresses, phytohormone signalling, plant developmental processes and miRNA biogenesis.
Collapse
Affiliation(s)
- Nur-Athirah Abd-Hamid
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor, Malaysia
| | - Muhammad-Izzat Ahmad-Fauzi
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor, Malaysia
| | - Zamri Zainal
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor, Malaysia
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor, Malaysia
| | - Ismanizan Ismail
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor, Malaysia.
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor, Malaysia.
| |
Collapse
|
14
|
van der Wel H, Gas-Pascual E, West CM. Skp1 isoforms are differentially modified by a dual function prolyl 4-hydroxylase/N-acety lglucosaminyltransferase in a plant pathogen. Glycobiology 2019; 29:705-714. [PMID: 31281925 PMCID: PMC6774341 DOI: 10.1093/glycob/cwz049] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 06/22/2019] [Accepted: 07/02/2019] [Indexed: 01/01/2023] Open
Abstract
Skp1 is hydroxylated by an O2-dependent prolyl hydroxylase (PhyA) that contributes to O2-sensing in the social amoeba Dictyostelium and the mammalian pathogen Toxoplasma gondii. HO-Skp1 is subject to glycosylation and the resulting pentasaccharide affects Skp1 conformation in a way that influences association of Skp1 with F-box proteins, and potentially the assembly of E3(SCF) ubiquitin ligase complexes that mediate the polyubiquitination of target proteins that are degraded in the 26S-proteasome. To investigate the conservation and specificity of these modifications, we analyzed proteins from the oomycete Pythium ultimum, an important crop plant pathogen. Putative coding sequences for Pythium's predicted PhyA and first glycosyltransferase in the predicted five-enzyme pathway, a GlcNAc-transferase (Gnt1), predict a bifunctional enzyme (Phgt) that, when expressed in Dictyostelium, rescued a knockout of phyA but not gnt1. Though recombinant Phgt was also unable to glycosylate Dictyostelium HO-Skp1, it could hydrolyze UDP-GlcNAc and modify a synthetic hydroxypeptide from Dictyostelium Skp1. Pythium encodes two highly similar Skp1 isoforms, but only Skp1A was efficiently hydroxylated and glycosylated in vitro. While kinetic analysis revealed no evidence for processive processing of Skp1, the physical linkage of the two activities implies dedication to Skp1 in vivo. These findings indicate a widespread occurrence of the Skp1 modification pathway across protist phylogeny, suggest that both Gnt1 and PhyA are specific for Skp1 and indicate that the second Skp1 provides a bypass mechanism for O2-regulation in Pythium and other protists that conserve this gene.
Collapse
Affiliation(s)
- Hanke van der Wel
- Department of Biochemistry & Molecular Biology, Center for Tropical & Emerging Global Diseases, Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
| | - Elisabet Gas-Pascual
- Department of Biochemistry & Molecular Biology, Center for Tropical & Emerging Global Diseases, Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
| | - Christopher M West
- Department of Biochemistry & Molecular Biology, Center for Tropical & Emerging Global Diseases, Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
| |
Collapse
|
15
|
Baptista CG, Lis A, Deng B, Gas-Pascual E, Dittmar A, Sigurdson W, West CM, Blader IJ. Toxoplasma F-box protein 1 is required for daughter cell scaffold function during parasite replication. PLoS Pathog 2019; 15:e1007946. [PMID: 31348812 PMCID: PMC6685633 DOI: 10.1371/journal.ppat.1007946] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 08/07/2019] [Accepted: 06/27/2019] [Indexed: 01/06/2023] Open
Abstract
By binding to the adaptor protein SKP1 and serving as substrate receptors for the SKP1 Cullin, F-box E3 ubiquitin ligase complex, F-box proteins regulate critical cellular processes including cell cycle progression and membrane trafficking. While F-box proteins are conserved throughout eukaryotes and are well studied in yeast, plants, and animals, studies in parasitic protozoa are lagging. We have identified eighteen putative F-box proteins in the Toxoplasma genome of which four have predicted homologs in Plasmodium. Two of the conserved F-box proteins were demonstrated to be important for Toxoplasma fitness and here we focus on an F-box protein, named TgFBXO1, because it is the most highly expressed by replicative tachyzoites and was also identified in an interactome screen as a Toxoplasma SKP1 binding protein. TgFBXO1 interacts with Toxoplasma SKP1 confirming it as a bona fide F-box protein. In interphase parasites, TgFBXO1 is a component of the Inner Membrane Complex (IMC), which is an organelle that underlies the plasma membrane. Early during replication, TgFBXO1 localizes to the developing daughter cell scaffold, which is the site where the daughter cell IMC and microtubules form and extend from. TgFBXO1 localization to the daughter cell scaffold required centrosome duplication but before kinetochore separation was completed. Daughter cell scaffold localization required TgFBXO1 N-myristoylation and was dependent on the small molecular weight GTPase, TgRab11b. Finally, we demonstrate that TgFBXO1 is required for parasite growth due to its function as a daughter cell scaffold effector. TgFBXO1 is the first F-box protein to be studied in apicomplexan parasites and represents the first protein demonstrated to be important for daughter cell scaffold function.
Collapse
Affiliation(s)
- Carlos Gustavo Baptista
- Department of Microbiology and Immunology, University at Buffalo School of Medicine, Buffalo, New York, United States of America
| | - Agnieszka Lis
- Department of Microbiology and Immunology, University at Buffalo School of Medicine, Buffalo, New York, United States of America
| | - Bowen Deng
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Elisabet Gas-Pascual
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Ashley Dittmar
- Department of Microbiology and Immunology, University at Buffalo School of Medicine, Buffalo, New York, United States of America
| | - Wade Sigurdson
- Department of Physiology and Biophysics, University at Buffalo School of Medicine, Buffalo, New York, United States of America
| | - Christopher M. West
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Ira J. Blader
- Department of Microbiology and Immunology, University at Buffalo School of Medicine, Buffalo, New York, United States of America
| |
Collapse
|
16
|
West CM, Kim HW. Nucleocytoplasmic O-glycosylation in protists. Curr Opin Struct Biol 2019; 56:204-212. [PMID: 31128470 DOI: 10.1016/j.sbi.2019.03.031] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 03/19/2019] [Accepted: 03/31/2019] [Indexed: 12/17/2022]
Abstract
O-Glycosylation is an increasingly recognized modification of intracellular proteins in all kingdoms of life, and its occurrence in protists has been investigated to understand its evolution and its roles in the virulence of unicellular pathogens. We focus here on two kinds of glycoregulation found in unicellular eukaryotes: one is a simple O-fucose modification of dozens if not hundreds of Ser/Thr-rich proteins, and the other a complex pentasaccharide devoted to a single protein associated with oxygen sensing and the assembly of polyubiquitin chains. These modifications are not required for life but contingently modulate biological processes in the social amoeba Dictyostelium and the human pathogen Toxoplasma gondii, and likely occur in diverse unicellular protists. O-Glycosylation that is co-localized in the cytoplasm allows for glycoregulation over the entire life of the protein, contrary to the secretory pathway where glycosylation usually occurs before its delivery to its site of function. Here, we interpret cellular roles of nucleocytoplasmic glycans in terms of current evidence for their effects on the conformation and dynamics of protist proteins, to serve as a guide for future studies to examine their broader significance.
Collapse
Affiliation(s)
- Christopher M West
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA 30602 USA; Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602 USA; Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602 USA.
| | - Hyun W Kim
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA 30602 USA
| |
Collapse
|
17
|
Xu X, Eletsky A, Sheikh MO, Prestegard JH, West CM. Glycosylation Promotes the Random Coil to Helix Transition in a Region of a Protist Skp1 Associated with F-Box Binding. Biochemistry 2017; 57:511-515. [PMID: 29251491 DOI: 10.1021/acs.biochem.7b01033] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cullin-ring-ligases mediate protein polyubiquitination, a signal for degradation in the 26S proteasome. The CRL1 class consists of Skp1/cullin-1/F-box protein/Rbx1 (SCF) complexes that cyclically associate with ubiquitin-E2 to build the polyubiquitin chain. Within the SCF complex, the 162-amino acid DdSkp1 from Dictyostelium bridges cullin-1 with an F-box protein (FBP), the specificity factor for substrate selection. The hydroxylation-dependent glycosylation of Pro143 of DdSkp1 by a pentasaccharide forms the basis of a novel O2-sensing mechanism in the social amoeba Dictyostelium and other protists. Previous evidence indicated that glycosylation promotes increased α-helical content correlating with enhanced interaction with three F-box proteins. To localize these differences, we used nuclear magnetic resonance (NMR) methods to compare nonglycosylated DdSkp1 and a glycoform with a single GlcNAc sugar (Gn-DdSkp1). We report NMR assignments of backbone 1HN, 15N, 13Cα, and 13CO nuclei as well as side-chain 13Cβ and methyl 13C/1H nuclei of Ile(δ1), Leu, and Val in both unmodified DdSkp1 and Gn-DdSkp1. The random coil index and 15N{1H} HNOE indicate that the C-terminal region, which forms a helix-loop-helix motif centered on Pro143 at the crystallographically defined binding interface with F-box domains, remains dynamic in both DdSkp1 and Gn-DdSkp1. Chemical shifts indicate that the variation of conformation in Gn-DdSkp1, relative to DdSkp1, is limited to this region and characterized by increased helical fold. Extension of the glycan chain results in further changes, also limited to this region. Thus, glycosylation may control F-box protein interactions via a local effect on DdSkp1 conformation, by a mechanism that may be general to many unicellular eukaryotes.
Collapse
Affiliation(s)
- Xianzhong Xu
- Department of Biochemistry & Molecular Biology, ‡Complex Carbohydrate Research Center, and §Center for Tropical and Emerging Global Diseases, University of Georgia , Athens, Georgia 30602, United States
| | - Alexander Eletsky
- Department of Biochemistry & Molecular Biology, ‡Complex Carbohydrate Research Center, and §Center for Tropical and Emerging Global Diseases, University of Georgia , Athens, Georgia 30602, United States
| | - M Osman Sheikh
- Department of Biochemistry & Molecular Biology, ‡Complex Carbohydrate Research Center, and §Center for Tropical and Emerging Global Diseases, University of Georgia , Athens, Georgia 30602, United States
| | - James H Prestegard
- Department of Biochemistry & Molecular Biology, ‡Complex Carbohydrate Research Center, and §Center for Tropical and Emerging Global Diseases, University of Georgia , Athens, Georgia 30602, United States
| | - Christopher M West
- Department of Biochemistry & Molecular Biology, ‡Complex Carbohydrate Research Center, and §Center for Tropical and Emerging Global Diseases, University of Georgia , Athens, Georgia 30602, United States
| |
Collapse
|
18
|
Sheikh MO, Thieker D, Chalmers G, Schafer CM, Ishihara M, Azadi P, Woods RJ, Glushka JN, Bendiak B, Prestegard JH, West CM. O 2 sensing-associated glycosylation exposes the F-box-combining site of the Dictyostelium Skp1 subunit in E3 ubiquitin ligases. J Biol Chem 2017; 292:18897-18915. [PMID: 28928219 PMCID: PMC5704474 DOI: 10.1074/jbc.m117.809160] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 09/12/2017] [Indexed: 11/06/2022] Open
Abstract
Skp1 is a conserved protein linking cullin-1 to F-box proteins in SCF (Skp1/Cullin-1/F-box protein) E3 ubiquitin ligases, which modify protein substrates with polyubiquitin chains that typically target them for 26S proteasome-mediated degradation. In Dictyostelium (a social amoeba), Toxoplasma gondii (the agent for human toxoplasmosis), and other protists, Skp1 is regulated by a unique pentasaccharide attached to hydroxylated Pro-143 within its C-terminal F-box-binding domain. Prolyl hydroxylation of Skp1 contributes to O2-dependent Dictyostelium development, but full glycosylation at that position is required for optimal O2 sensing. Previous studies have shown that the glycan promotes organization of the F-box-binding region in Skp1 and aids in Skp1's association with F-box proteins. Here, NMR and MS approaches were used to determine the glycan structure, and then a combination of NMR and molecular dynamics simulations were employed to characterize the impact of the glycan on the conformation and motions of the intrinsically flexible F-box-binding domain of Skp1. Molecular dynamics trajectories of glycosylated Skp1 whose calculated monosaccharide relaxation kinetics and rotational correlation times agreed with the NMR data indicated that the glycan interacts with the loop connecting two α-helices of the F-box-combining site. In these trajectories, the helices separated from one another to create a more accessible and dynamic F-box interface. These results offer an unprecedented view of how a glycan modification influences a disordered region of a full-length protein. The increased sampling of an open Skp1 conformation can explain how glycosylation enhances interactions with F-box proteins in cells.
Collapse
Affiliation(s)
- M Osman Sheikh
- From the Department of Biochemistry and Molecular Biology
- the Complex Carbohydrate Research Center, and
- the Department of Biochemistry and Molecular Biology, Oklahoma Center for Medical Glycobiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, and
| | | | - Gordon Chalmers
- the Complex Carbohydrate Research Center, and
- the Department of Computer Science, University of Georgia, Athens, Georgia 30602
| | - Christopher M Schafer
- the Department of Biochemistry and Molecular Biology, Oklahoma Center for Medical Glycobiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, and
| | | | | | - Robert J Woods
- From the Department of Biochemistry and Molecular Biology
- the Complex Carbohydrate Research Center, and
| | | | - Brad Bendiak
- the Department of Cell and Developmental Biology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
| | - James H Prestegard
- From the Department of Biochemistry and Molecular Biology
- the Complex Carbohydrate Research Center, and
| | - Christopher M West
- From the Department of Biochemistry and Molecular Biology,
- the Department of Biochemistry and Molecular Biology, Oklahoma Center for Medical Glycobiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, and
| |
Collapse
|
19
|
Rahman K, Mandalasi M, Zhao P, Sheikh MO, Taujale R, Kim HW, van der Wel H, Matta K, Kannan N, Glushka JN, Wells L, West CM. Characterization of a cytoplasmic glucosyltransferase that extends the core trisaccharide of the Toxoplasma Skp1 E3 ubiquitin ligase subunit. J Biol Chem 2017; 292:18644-18659. [PMID: 28928220 DOI: 10.1074/jbc.m117.809301] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 09/12/2017] [Indexed: 01/06/2023] Open
Abstract
Skp1 is a subunit of the SCF (Skp1/Cullin 1/F-box protein) class of E3 ubiquitin ligases that are important for eukaryotic protein degradation. Unlike its animal counterparts, Skp1 from Toxoplasma gondii is hydroxylated by an O2-dependent prolyl-4-hydroxylase (PhyA), and the resulting hydroxyproline can subsequently be modified by a five-sugar chain. A similar modification is found in the social amoeba Dictyostelium, where it regulates SCF assembly and O2-dependent development. Homologous glycosyltransferases assemble a similar core trisaccharide in both organisms, and a bifunctional α-galactosyltransferase from CAZy family GT77 mediates the addition of the final two sugars in Dictyostelium, generating Galα1, 3Galα1,3Fucα1,2Galβ1,3GlcNAcα1-. Here, we found that Toxoplasma utilizes a cytoplasmic glycosyltransferase from an ancient clade of CAZy family GT32 to catalyze transfer of the fourth sugar. Catalytically active Glt1 was required for the addition of the terminal disaccharide in cells, and cytosolic extracts catalyzed transfer of [3H]glucose from UDP-[3H]glucose to the trisaccharide form of Skp1 in a glt1-dependent fashion. Recombinant Glt1 catalyzed the same reaction, confirming that it directly mediates Skp1 glucosylation, and NMR demonstrated formation of a Glcα1,3Fuc linkage. Recombinant Glt1 strongly preferred the full core trisaccharide attached to Skp1 and labeled only Skp1 in glt1Δ extracts, suggesting specificity for Skp1. glt1-knock-out parasites exhibited a growth defect not rescued by catalytically inactive Glt1, indicating that the glycan acts in concert with the first enzyme in the pathway, PhyA, in cells. A genomic bioinformatics survey suggested that Glt1 belongs to the ancestral Skp1 glycosylation pathway in protists and evolved separately from related Golgi-resident GT32 glycosyltransferases.
Collapse
Affiliation(s)
- Kazi Rahman
- From the Department of Biochemistry and Molecular Biology.,the Departments of Microbiology and Immunology and
| | - Msano Mandalasi
- From the Department of Biochemistry and Molecular Biology.,Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, and
| | - Peng Zhao
- the Complex Carbohydrate Research Center, and
| | | | - Rahil Taujale
- the Complex Carbohydrate Research Center, and.,the Institute of Bioinformatics, University of Georgia, Athens, Georgia 30602
| | - Hyun W Kim
- From the Department of Biochemistry and Molecular Biology
| | | | - Khushi Matta
- the Department of Chemical and Biological Engineering, State University of New York, Buffalo, New York 14260
| | - Natarajan Kannan
- From the Department of Biochemistry and Molecular Biology.,the Institute of Bioinformatics, University of Georgia, Athens, Georgia 30602
| | | | - Lance Wells
- From the Department of Biochemistry and Molecular Biology.,the Complex Carbohydrate Research Center, and
| | - Christopher M West
- From the Department of Biochemistry and Molecular Biology, .,Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, and
| |
Collapse
|
20
|
Abstract
Simple and complex carbohydrates (glycans) have long been known to play major metabolic, structural and physical roles in biological systems. Targeted microbial binding to host glycans has also been studied for decades. But such biological roles can only explain some of the remarkable complexity and organismal diversity of glycans in nature. Reviewing the subject about two decades ago, one could find very few clear-cut instances of glycan-recognition-specific biological roles of glycans that were of intrinsic value to the organism expressing them. In striking contrast there is now a profusion of examples, such that this updated review cannot be comprehensive. Instead, a historical overview is presented, broad principles outlined and a few examples cited, representing diverse types of roles, mediated by various glycan classes, in different evolutionary lineages. What remains unchanged is the fact that while all theories regarding biological roles of glycans are supported by compelling evidence, exceptions to each can be found. In retrospect, this is not surprising. Complex and diverse glycans appear to be ubiquitous to all cells in nature, and essential to all life forms. Thus, >3 billion years of evolution consistently generated organisms that use these molecules for many key biological roles, even while sometimes coopting them for minor functions. In this respect, glycans are no different from other major macromolecular building blocks of life (nucleic acids, proteins and lipids), simply more rapidly evolving and complex. It is time for the diverse functional roles of glycans to be fully incorporated into the mainstream of biological sciences.
Collapse
Affiliation(s)
- Ajit Varki
- Departments of Medicine and Cellular & Molecular Medicine, Glycobiology Research and Training Center, University of California at San Diego, La Jolla, CA 92093-0687, USA
| |
Collapse
|
21
|
Rahman K, Zhao P, Mandalasi M, van der Wel H, Wells L, Blader IJ, West CM. The E3 Ubiquitin Ligase Adaptor Protein Skp1 Is Glycosylated by an Evolutionarily Conserved Pathway That Regulates Protist Growth and Development. J Biol Chem 2016; 291:4268-80. [PMID: 26719340 PMCID: PMC4813455 DOI: 10.1074/jbc.m115.703751] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 12/19/2015] [Indexed: 01/12/2023] Open
Abstract
Toxoplasma gondii is a protist parasite of warm-blooded animals that causes disease by proliferating intracellularly in muscle and the central nervous system. Previous studies showed that a prolyl 4-hydroxylase related to animal HIFα prolyl hydroxylases is required for optimal parasite proliferation, especially at low O2. We also observed that Pro-154 of Skp1, a subunit of the Skp1/Cullin-1/F-box protein (SCF)-class of E3-ubiquitin ligases, is a natural substrate of this enzyme. In an unrelated protist, Dictyostelium discoideum, Skp1 hydroxyproline is modified by five sugars via the action of three glycosyltransferases, Gnt1, PgtA, and AgtA, which are required for optimal O2-dependent development. We show here that TgSkp1 hydroxyproline is modified by a similar pentasaccharide, based on mass spectrometry, and that assembly of the first three sugars is dependent on Toxoplasma homologs of Gnt1 and PgtA. Reconstitution of the glycosyltransferase reactions in extracts with radioactive sugar nucleotide substrates and appropriate Skp1 glycoforms, followed by chromatographic analysis of acid hydrolysates of the reaction products, confirmed the predicted sugar identities as GlcNAc, Gal, and Fuc. Disruptions of gnt1 or pgtA resulted in decreased parasite growth. Off target effects were excluded based on restoration of the normal glycan chain and growth upon genetic complementation. By analogy to Dictyostelium Skp1, the mechanism may involve regulation of assembly of the SCF complex. Understanding the mechanism of Toxoplasma Skp1 glycosylation is expected to help develop it as a drug target for control of the pathogen, as the glycosyltransferases are absent from mammalian hosts.
Collapse
Affiliation(s)
- Kazi Rahman
- From the Departments of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, the Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602, the Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Peng Zhao
- the Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602, the Complex Carbohydrate Research Center, Athens, Georgia 30602, and
| | - Msano Mandalasi
- From the Departments of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, the Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602
| | - Hanke van der Wel
- From the Departments of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, the Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602
| | - Lance Wells
- the Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602, the Complex Carbohydrate Research Center, Athens, Georgia 30602, and
| | - Ira J Blader
- the Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, the Department of Microbiology and Immunology, University at Buffalo, Buffalo, New York 14214
| | - Christopher M West
- From the Departments of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, the Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602,
| |
Collapse
|
22
|
Chinoy ZS, Schafer CM, West CM, Boons GJ. Chemical Synthesis of a Glycopeptide Derived from Skp1 for Probing Protein Specific Glycosylation. Chemistry 2015; 21:11779-87. [PMID: 26179871 DOI: 10.1002/chem.201501598] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Indexed: 01/13/2023]
Abstract
Skp1 is a cytoplasmic and nuclear protein, best known as an adaptor of the SCF family of E3-ubiquitin ligases that label proteins for their degradation. Skp1 in Dictyostelium is posttranslationally modified on a specific hydroxyproline (Hyp) residue by a pentasaccharide, which consists of a Fucα1,2-Galβ-1,3-GlcNAcα core, decorated with two α-linked Gal residues. A glycopeptide derived form Skp1 was prepared to characterize the α-galactosyltransferase (AgtA) that mediates the addition of the α-Gal moieties, and to develop antibodies suitable for tracking the trisaccharide isoform of Skp1 in cells. A strategy was developed for the synthesis of the core trisaccharide-Hyp based on the use of 2-naphthylmethyl (Nap) ethers as permanent protecting groups to allow late stage installation of the Hyp moiety. Tuning of glycosyl donor and acceptor reactivities was critical for achieving high yields and anomeric selectivities of glycosylations. The trisaccharide-Hyp moiety was employed for the preparation of the glycopeptide using microwave-assisted solid phase peptide synthesis. Enzyme kinetic studies revealed that trisaccharide-Hyp and trisaccharide-peptide are poorly recognized by AgtA, indicating the importance of context provided by the native Skp1 protein for engagement with the active site. The trisaccharide-peptide was a potent immunogen capable of generating a rabbit antiserum that was highly selective toward the trisaccharide isoform of full-length Skp1.
Collapse
Affiliation(s)
- Zoeisha S Chinoy
- Complex Carbohydrate Research Center and Department of Chemistry, University of Georgia, 315 Riverbend Road, Athens, GA 30602 (USA)
| | - Christopher M Schafer
- Department of Biochemistry and Molecular Biology and Oklahoma Center for Medical Glycobiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104 (USA).,Current address: Oklahoma Medical Research Foundation, 825 N.E. 13th Street, Oklahoma City, OK 73104 (USA)
| | - Christopher M West
- Department of Biochemistry and Molecular Biology and Oklahoma Center for Medical Glycobiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104 (USA).,Current address: Dept. of Biochemistry and Molecular Biology, University of Georgia, 120 Green Street, Athens, GA 30602 (USA)
| | - Geert-Jan Boons
- Complex Carbohydrate Research Center and Department of Chemistry, University of Georgia, 315 Riverbend Road, Athens, GA 30602 (USA).
| |
Collapse
|
23
|
West CM, Blader IJ. Oxygen sensing by protozoans: how they catch their breath. Curr Opin Microbiol 2015; 26:41-7. [PMID: 25988702 DOI: 10.1016/j.mib.2015.04.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2015] [Accepted: 04/24/2015] [Indexed: 01/09/2023]
Abstract
Cells must know the local levels of available oxygen and either adapt accordingly or relocate to more favorable environments. Prolyl 4-hydroxylases (P4Hs) are emerging as universal cellular oxygen sensors. In animals, these oxygen sensors respond to decreased oxygen availability by up-regulating hypoxia-inducible transcription factors. In protozoa, the P4Hs appear to activate E3-SCF ubiquitin ligase complexes via a glycosylation-dependent mechanism, potentially to turn over their proteomes. Intracellular parasites are impacted by both types of oxygen-sensing pathways. Since parasites are exposed to diverse oxygen tensions during their life cycles, this review identifies emerging oxygen-sensing mechanisms and discusses how these mechanisms probably contribute to the regulation of unicellular eukaryotes.
Collapse
Affiliation(s)
- Christopher M West
- Department of Biochemistry & Molecular Biology, Oklahoma Center for Medical Glycobiology, University of Oklahoma Health Sciences Center, 975 NE 10th St., BRC 417, Oklahoma City, OK 73104, USA.
| | - Ira J Blader
- Department of Microbiology and Immunology, University at Buffalo School of Medicine, 347 Biomedical Research Building, 3435 Main Street, Buffalo, NY 14214, USA
| |
Collapse
|