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Pasquarelli RR, Sha J, Wohlschlegel JA, Bradley PJ. BCC0 collaborates with IMC32 and IMC43 to form the Toxoplasma gondii essential daughter bud assembly complex. PLoS Pathog 2024; 20:e1012411. [PMID: 39024411 PMCID: PMC11288415 DOI: 10.1371/journal.ppat.1012411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Revised: 07/30/2024] [Accepted: 07/10/2024] [Indexed: 07/20/2024] Open
Abstract
Toxoplasma gondii divides by endodyogeny, in which two daughter buds are formed within the cytoplasm of the maternal cell using the inner membrane complex (IMC) as a scaffold. During endodyogeny, components of the IMC are synthesized and added sequentially to the nascent daughter buds in a tightly regulated manner. We previously showed that the early recruiting proteins IMC32 and IMC43 form an essential daughter bud assembly complex which lays the foundation of the daughter cell scaffold in T. gondii. In this study, we identify the essential, early recruiting IMC protein BCC0 as a third member of this complex by using IMC32 as bait in both proximity labeling and yeast two-hybrid screens. We demonstrate that BCC0's localization to daughter buds depends on the presence of both IMC32 and IMC43. Deletion analyses and functional complementation studies reveal that residues 701-877 of BCC0 are essential for both its localization and function and that residues 1-899 are sufficient for function despite minor mislocalization. Pairwise yeast two-hybrid assays additionally demonstrate that BCC0's essential domain binds to the coiled-coil region of IMC32 and that BCC0 and IMC43 do not directly interact. This data supports a model for complex assembly in which an IMC32-BCC0 subcomplex initially recruits to nascent buds via palmitoylation of IMC32 and is locked into the scaffold once bud elongation begins by IMC32 binding to IMC43. Together, this study dissects the organization and function of a complex of three early recruiting daughter proteins which are essential for the proper assembly of the IMC during endodyogeny.
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Affiliation(s)
- Rebecca R. Pasquarelli
- Molecular Biology Institute, University of California, Los Angeles, California, United States of America
| | - Jihui Sha
- Department of Biological Chemistry and Institute of Genomics and Proteomics, University of California, Los Angeles, California, United States of America
| | - James A. Wohlschlegel
- Department of Biological Chemistry and Institute of Genomics and Proteomics, University of California, Los Angeles, California, United States of America
| | - Peter J. Bradley
- Molecular Biology Institute, University of California, Los Angeles, California, United States of America
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, California, United States of America
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2
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Pasquarelli RR, Quan JJ, Cheng ES, Yang V, Britton TA, Sha J, Wohlschlegel JA, Bradley PJ. Characterization and functional analysis of Toxoplasma Golgi-associated proteins identified by proximity labelling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.02.578703. [PMID: 38352341 PMCID: PMC10862792 DOI: 10.1101/2024.02.02.578703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2024]
Abstract
Toxoplasma gondii possesses a highly polarized secretory pathway that contains both broadly conserved eukaryotic organelles and unique apicomplexan organelles which play essential roles in the parasite's lytic cycle. As in other eukaryotes, the T. gondii Golgi apparatus sorts and modifies proteins prior to their distribution to downstream organelles. Many of the typical trafficking factors found involved in these processes are missing from apicomplexan genomes, suggesting that these parasites have evolved unique proteins to fill these roles. Here we identify a novel Golgi-localizing protein (ULP1) which contains structural homology to the eukaryotic trafficking factor p115/Uso1. We demonstrate that depletion of ULP1 leads to a dramatic reduction in parasite fitness and replicative ability. Using ULP1 as bait for TurboID proximity labelling and immunoprecipitation, we identify eleven more novel Golgi-associated proteins and demonstrate that ULP1 interacts with the T. gondii COG complex. These proteins include both conserved trafficking factors and parasite-specific proteins. Using a conditional knockdown approach, we assess the effect of each of these eleven proteins on parasite fitness. Together, this work reveals a diverse set of novel T. gondii Golgi-associated proteins that play distinct roles in the secretory pathway. As several of these proteins are absent outside of the Apicomplexa, they represent potential targets for the development of novel therapeutics against these parasites. Importance Apicomplexan parasites such as Toxoplasma gondii infect a large percentage of the world's population and cause substantial human disease. These widespread pathogens use specialized secretory organelles to infect their host cells, modulate host cell functions, and cause disease. While the functions of the secretory organelles are now better understood, the Golgi apparatus of the parasite remains largely unexplored, particularly regarding parasite-specific innovations that may help direct traffic intracellularly. In this work, we characterize ULP1, a protein that is unique to parasites but shares structural similarity to the eukaryotic trafficking factor p115/Uso1. We show that ULP1 plays an important role in parasite replication and demonstrate that it interacts with the conserved oligomeric Golgi (COG) complex. We then use ULP1 proximity labelling to identify eleven additional Golgi-associated proteins which we functionally analyze via conditional knockdown. This work expands our knowledge of the Toxoplasma Golgi apparatus and identifies potential targets for therapeutic intervention.
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Pasquarelli RR, Back PS, Sha J, Wohlschlegel JA, Bradley PJ. Identification of IMC43, a novel IMC protein that collaborates with IMC32 to form an essential daughter bud assembly complex in Toxoplasma gondii. PLoS Pathog 2023; 19:e1011707. [PMID: 37782662 PMCID: PMC10569561 DOI: 10.1371/journal.ppat.1011707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 10/12/2023] [Accepted: 09/23/2023] [Indexed: 10/04/2023] Open
Abstract
The inner membrane complex (IMC) of Toxoplasma gondii is essential for all phases of the parasite's life cycle. One of its most critical roles is to act as a scaffold for the assembly of daughter buds during replication by endodyogeny. While many daughter IMC proteins have been identified, most are recruited after bud initiation and are not essential for parasite fitness. Here, we report the identification of IMC43, a novel daughter IMC protein that is recruited at the earliest stages of daughter bud initiation. Using an auxin-inducible degron system we show that depletion of IMC43 results in aberrant morphology, dysregulation of endodyogeny, and an extreme defect in replication. Deletion analyses reveal a region of IMC43 that plays a role in localization and a C-terminal domain that is essential for the protein's function. TurboID proximity labelling and a yeast two-hybrid screen using IMC43 as bait identify 30 candidate IMC43 binding partners. We investigate two of these: the essential daughter protein IMC32 and a novel daughter IMC protein we named IMC44. We show that IMC43 is responsible for regulating the localization of both IMC32 and IMC44 at specific stages of endodyogeny and that this regulation is dependent on the essential C-terminal domain of IMC43. Using pairwise yeast two-hybrid assays, we determine that this region is also sufficient for binding to both IMC32 and IMC44. As IMC43 and IMC32 are both essential proteins, this work reveals the existence of a bud assembly complex that forms the foundation of the daughter IMC during endodyogeny.
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Affiliation(s)
- Rebecca R. Pasquarelli
- Molecular Biology Institute, University of California, Los Angeles, California, United States of America
| | - Peter S. Back
- Molecular Biology Institute, University of California, Los Angeles, California, United States of America
| | - Jihui Sha
- Department of Biological Chemistry and Institute of Genomics and Proteomics, University of California, Los Angeles, California, United States of America
| | - James A. Wohlschlegel
- Department of Biological Chemistry and Institute of Genomics and Proteomics, University of California, Los Angeles, California, United States of America
| | - Peter J. Bradley
- Molecular Biology Institute, University of California, Los Angeles, California, United States of America
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, California, United States of America
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Guo J, Guo S, Lu S, Gong J, Wang L, Ding L, Chen Q, Liu W. The development of proximity labeling technology and its applications in mammals, plants, and microorganisms. Cell Commun Signal 2023; 21:269. [PMID: 37777761 PMCID: PMC10544124 DOI: 10.1186/s12964-023-01310-1] [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: 07/31/2023] [Accepted: 09/07/2023] [Indexed: 10/02/2023] Open
Abstract
Protein‒protein, protein‒RNA, and protein‒DNA interaction networks form the basis of cellular regulation and signal transduction, making it crucial to explore these interaction networks to understand complex biological processes. Traditional methods such as affinity purification and yeast two-hybrid assays have been shown to have limitations, as they can only isolate high-affinity molecular interactions under nonphysiological conditions or in vitro. Moreover, these methods have shortcomings for organelle isolation and protein subcellular localization. To address these issues, proximity labeling techniques have been developed. This technology not only overcomes the limitations of traditional methods but also offers unique advantages in studying protein spatial characteristics and molecular interactions within living cells. Currently, this technique not only is indispensable in research on mammalian nucleoprotein interactions but also provides a reliable approach for studying nonmammalian cells, such as plants, parasites and viruses. Given these advantages, this article provides a detailed introduction to the principles of proximity labeling techniques and the development of labeling enzymes. The focus is on summarizing the recent applications of TurboID and miniTurbo in mammals, plants, and microorganisms. Video Abstract.
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Affiliation(s)
- Jieyu Guo
- School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology, Xianning, Hubei, 437000, China
- School of Pharmacy, Xianning Medical College, Hubei University of Science and Technology, Xianning, Hubei, 437000, China
| | - Shuang Guo
- Medicine Research Institute, Hubei Key Laboratory of Diabetes and Angiopathy, Xianning Medical College, Hubei University of Science and Technology, Xianning, Hubei, 437000, China
| | - Siao Lu
- School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology, Xianning, Hubei, 437000, China
- School of Pharmacy, Xianning Medical College, Hubei University of Science and Technology, Xianning, Hubei, 437000, China
| | - Jun Gong
- School of Pharmacy, Xianning Medical College, Hubei University of Science and Technology, Xianning, Hubei, 437000, China
| | - Long Wang
- School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology, Xianning, Hubei, 437000, China
| | - Liqiong Ding
- School of Pharmacy, Xianning Medical College, Hubei University of Science and Technology, Xianning, Hubei, 437000, China
| | - Qingjie Chen
- School of Pharmacy, Xianning Medical College, Hubei University of Science and Technology, Xianning, Hubei, 437000, China.
| | - Wu Liu
- School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology, Xianning, Hubei, 437000, China.
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Kent RS, Briggs EM, Colon BL, Alvarez C, Silva Pereira S, De Niz M. Paving the Way: Contributions of Big Data to Apicomplexan and Kinetoplastid Research. Front Cell Infect Microbiol 2022; 12:900878. [PMID: 35734575 PMCID: PMC9207352 DOI: 10.3389/fcimb.2022.900878] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 05/06/2022] [Indexed: 11/13/2022] Open
Abstract
In the age of big data an important question is how to ensure we make the most out of the resources we generate. In this review, we discuss the major methods used in Apicomplexan and Kinetoplastid research to produce big datasets and advance our understanding of Plasmodium, Toxoplasma, Cryptosporidium, Trypanosoma and Leishmania biology. We debate the benefits and limitations of the current technologies, and propose future advancements that may be key to improving our use of these techniques. Finally, we consider the difficulties the field faces when trying to make the most of the abundance of data that has already been, and will continue to be, generated.
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Affiliation(s)
- Robyn S. Kent
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT, United States
| | - Emma M. Briggs
- Institute for Immunology and Infection Research, School of Biological Sciences, University Edinburgh, Edinburgh, United Kingdom
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Beatrice L. Colon
- Wellcome Centre for Anti-Infectives Research, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Catalina Alvarez
- de Duve Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Sara Silva Pereira
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisboa, Portugal
| | - Mariana De Niz
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisboa, Portugal
- Institut Pasteur, Paris, France
- *Correspondence: Mariana De Niz,
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Wang H, Chan TW, Vashisht AA, Drew BG, Calkin AC, Harris TE, Wohlschlegel JA, Xiao X, Reue K. Lipin 1 modulates mRNA splicing during fasting adaptation in liver. JCI Insight 2021; 6:e150114. [PMID: 34494556 PMCID: PMC8492312 DOI: 10.1172/jci.insight.150114] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 07/23/2021] [Indexed: 01/03/2023] Open
Abstract
Lipin 1 regulates cellular lipid homeostasis through roles in glycerolipid synthesis (through phosphatidic acid phosphatase activity) and transcriptional coactivation. Lipin 1-deficient individuals exhibit episodic disease symptoms that are triggered by metabolic stress, such as stress caused by prolonged fasting. We sought to identify critical lipin 1 activities during fasting. We determined that lipin 1 deficiency induces widespread alternative mRNA splicing in liver during fasting, much of which is normalized by refeeding. The role of lipin 1 in mRNA splicing was largely independent of its enzymatic function. We identified interactions between lipin 1 and spliceosome proteins, as well as a requirement for lipin 1 to maintain homeostatic levels of spliceosome small nuclear RNAs and specific RNA splicing factors. In fasted Lpin1-/- liver, we identified a correspondence between alternative splicing of phospholipid biosynthetic enzymes and dysregulated phospholipid levels; splicing patterns and phospholipid levels were partly normalized by feeding. Thus, lipin 1 influences hepatic lipid metabolism through mRNA splicing, as well as through enzymatic and transcriptional activities, and fasting exacerbates the deleterious effects of lipin 1 deficiency on metabolic homeostasis.
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Affiliation(s)
- Huan Wang
- Human Genetics, David Geffen School of Medicine at UCLA
| | | | - Ajay A Vashisht
- Biological Chemistry, University of California, Los Angeles, California, USA
| | - Brian G Drew
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Anna C Calkin
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia.,Central Clinical School, Monash University, Melbourne, Victoria, Australia.,Baker Department of Cardiometabolic Health, University of Melbourne, Parkville, Victoria, Australia
| | - Thurl E Harris
- Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - James A Wohlschlegel
- Biological Chemistry, University of California, Los Angeles, California, USA.,Molecular Biology Institute and
| | - Xinshu Xiao
- Bioinformatics Interdepartmental Program and.,Molecular Biology Institute and.,Integrative Biology and Physiology, University of California, Los Angeles, California, USA
| | - Karen Reue
- Human Genetics, David Geffen School of Medicine at UCLA,,Molecular Biology Institute and
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7
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Proximity labeling in mammalian cells with TurboID and split-TurboID. Nat Protoc 2020; 15:3971-3999. [PMID: 33139955 DOI: 10.1038/s41596-020-0399-0] [Citation(s) in RCA: 159] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Accepted: 08/18/2020] [Indexed: 12/19/2022]
Abstract
This protocol describes the use of TurboID and split-TurboID in proximity labeling applications for mapping protein-protein interactions and subcellular proteomes in live mammalian cells. TurboID is an engineered biotin ligase that uses ATP to convert biotin into biotin-AMP, a reactive intermediate that covalently labels proximal proteins. Optimized using directed evolution, TurboID has substantially higher activity than previously described biotin ligase-related proximity labeling methods, such as BioID, enabling higher temporal resolution and broader application in vivo. Split-TurboID consists of two inactive fragments of TurboID that can be reconstituted through protein-protein interactions or organelle-organelle interactions, which can facilitate greater targeting specificity than full-length enzymes alone. Proteins biotinylated by TurboID or split-TurboID are then enriched with streptavidin beads and identified by mass spectrometry. Here, we describe fusion construct design and characterization (variable timing), proteomic sample preparation (5-7 d), mass spectrometric data acquisition (2 d), and proteomic data analysis (1 week).
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Nadipuram SM, Thind AC, Rayatpisheh S, Wohlschlegel JA, Bradley PJ. Proximity biotinylation reveals novel secreted dense granule proteins of Toxoplasma gondii bradyzoites. PLoS One 2020; 15:e0232552. [PMID: 32374791 PMCID: PMC7202600 DOI: 10.1371/journal.pone.0232552] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 04/16/2020] [Indexed: 02/06/2023] Open
Abstract
Toxoplasma gondii is an obligate intracellular parasite which is capable of establishing life-long chronic infection in any mammalian host. During the intracellular life cycle, the parasite secretes an array of proteins into the parasitophorous vacuole (PV) where it resides. Specialized organelles called the dense granules secrete GRA proteins that are known to participate in nutrient acquisition, immune evasion, and host cell-cycle manipulation. Although many GRAs have been discovered which are expressed during the acute infection mediated by tachyzoites, little is known about those that participate in the chronic infection mediated by the bradyzoite form of the parasite. In this study, we sought to uncover novel bradyzoite-upregulated GRA proteins using proximity biotinylation, which we previously used to examine the secreted proteome of the tachyzoites. Using a fusion of the bradyzoite upregulated protein MAG1 to BirA* as bait and a strain with improved switch efficiency, we identified a number of novel GRA proteins which are expressed in bradyzoites. After using the CRISPR/Cas9 system to characterize these proteins by gene knockout, we focused on one of these GRAs (GRA55) and found it was important for the establishment or maintenance of cysts in the mouse brain. These findings highlight new components of the GRA proteome of the tissue-cyst life stage of T. gondii and identify potential targets that are important for maintenance of parasite persistence in vivo.
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Affiliation(s)
- Santhosh Mukund Nadipuram
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, United States of America
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Cedar-Sinai Medical Center, Los Angeles, California, United States of America
| | - Amara Cervantes Thind
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, United States of America
- Molecular Biology Institute, University of California, Los Angeles, California, United States of America
| | - Shima Rayatpisheh
- Department of Biological Chemistry and Institute of Genomics and Proteomics, University of California, Los Angeles, California, United States of America
| | - James Akira Wohlschlegel
- Molecular Biology Institute, University of California, Los Angeles, California, United States of America
- Department of Biological Chemistry and Institute of Genomics and Proteomics, University of California, Los Angeles, California, United States of America
| | - Peter John Bradley
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, United States of America
- Molecular Biology Institute, University of California, Los Angeles, California, United States of America
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