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Herrera A, Packer MM, Rosas-Lemus M, Minasov G, Chen J, Brumell JH, Satchell KJF. Vibrio MARTX toxin processing and degradation of cellular Rab GTPases by the cytotoxic effector Makes Caterpillars Floppy. Proc Natl Acad Sci U S A 2024; 121:e2316143121. [PMID: 38861595 PMCID: PMC11194500 DOI: 10.1073/pnas.2316143121] [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: 09/22/2023] [Accepted: 04/19/2024] [Indexed: 06/13/2024] Open
Abstract
Vibrio vulnificus causes life-threatening wound and gastrointestinal infections, mediated primarily by the production of a Multifunctional-Autoprocessing Repeats-In-Toxin (MARTX) toxin. The most commonly present MARTX effector domain, the Makes Caterpillars Floppy-like (MCF) toxin, is a cysteine protease stimulated by host adenosine diphosphate (ADP) ribosylation factors (ARFs) to autoprocess. Here, we show processed MCF then binds and cleaves host Ras-related proteins in brain (Rab) guanosine triphosphatases within their C-terminal tails resulting in Rab degradation. We demonstrate MCF binds Rabs at the same interface occupied by ARFs. Moreover, we show MCF preferentially binds to ARF1 prior to autoprocessing and is active to cleave Rabs only subsequent to autoprocessing. We then use structure prediction algorithms to demonstrate that structural composition, rather than sequence, determines Rab target specificity. We further determine a crystal structure of aMCF as a swapped dimer, revealing an alternative conformation we suggest represents the open, activated state of MCF with reorganized active site residues. The cleavage of Rabs results in Rab1B dispersal within cells and loss of Rab1B density in the intestinal tissue of infected mice. Collectively, our work describes an extracellular bacterial mechanism whereby MCF is activated by ARFs and subsequently induces the degradation of another small host guanosine triphosphatase (GTPase), Rabs, to drive organelle damage, cell death, and promote pathogenesis of these rapidly fatal infections.
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Affiliation(s)
- Alfa Herrera
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
| | - Megan M. Packer
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
| | - Monica Rosas-Lemus
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
- Center for Structural Biology of Infectious Diseases, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
| | - George Minasov
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
- Center for Structural Biology of Infectious Diseases, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
| | - Jiexi Chen
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
| | - John H. Brumell
- Cell Biology Program, The Hospital for Sick Children, Toronto, ONM5G 0A4, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ONM5G 0A4, Canada
- Institute of Medical Science, University of Toronto, Toronto, ONM5S 1A8, Canada
- SickKids Inflammatory Bowel Disease Centre, The Hospital for Sick Children, Toronto, ONM5G 0A4, Canada
| | - Karla J. F. Satchell
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
- Center for Structural Biology of Infectious Diseases, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
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Hydrophobicity is a key determinant in the activity of arginine-rich cell penetrating peptides. Sci Rep 2022; 12:15981. [PMID: 36156072 PMCID: PMC9510126 DOI: 10.1038/s41598-022-20425-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 09/13/2022] [Indexed: 11/30/2022] Open
Abstract
To deliver useful biological payloads into the cytosolic space of cells, cell-penetrating peptides have to cross biological membranes. The molecular features that control or enhance this activity remain unclear. Herein, a dimeric template of the arginine-rich HIV TAT CPP was used to establish the effect of incorporating groups and residues of various chemical structures and properties. A positive correlation is established between the relative hydrophobicity of these additional moieties and the ability of the CPP conjugates to deliver a peptidic probe into live cells. CPP conjugates with low hydrophobicity lead to no detectable delivery activity, while CPPs containing groups of increasing hydrophobicity achieve intracellular delivery at low micromolar concentrations. Notably, the chemical structures of the hydrophobic groups do not appear to play a role in overall cell penetration activity. The cell penetration activity detected is consistent with endosomal escape. Leakage assays with lipid bilayer of endosomal membrane composition also establish a positive correlation between hydrophobicity and membrane permeation. Overall, these results indicate that the presence of a relatively hydrophobic moiety, regardless of structure, is required in a CPP structure to enhance its cell penetration. It also indicates that simple modifications, including fluorophores used for cell imaging or small payloads, modulate the activity of CPPs and that a given CPP-conjugate may be unique in its membrane permeation properties.
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Cellular Prion Protein (PrPc): Putative Interacting Partners and Consequences of the Interaction. Int J Mol Sci 2020; 21:ijms21197058. [PMID: 32992764 PMCID: PMC7583789 DOI: 10.3390/ijms21197058] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/20/2020] [Accepted: 09/23/2020] [Indexed: 02/08/2023] Open
Abstract
Cellular prion protein (PrPc) is a small glycosylphosphatidylinositol (GPI) anchored protein most abundantly found in the outer leaflet of the plasma membrane (PM) in the central nervous system (CNS). PrPc misfolding causes neurodegenerative prion diseases in the CNS. PrPc interacts with a wide range of protein partners because of the intrinsically disordered nature of the protein’s N-terminus. Numerous studies have attempted to decipher the physiological role of the prion protein by searching for proteins which interact with PrPc. Biochemical characteristics and biological functions both appear to be affected by interacting protein partners. The key challenge in identifying a potential interacting partner is to demonstrate that binding to a specific ligand is necessary for cellular physiological function or malfunction. In this review, we have summarized the intracellular and extracellular interacting partners of PrPc and potential consequences of their binding. We also briefly describe prion disease-related mutations at the end of this review.
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Pérez-Montesinos G, López-Ortega O, Piedra-Reyes J, Bonifaz LC, Moreno J. Dynamic Changes in the Intracellular Association of Selected Rab Small GTPases with MHC Class II and DM during Dendritic Cell Maturation. Front Immunol 2017; 8:340. [PMID: 28396666 PMCID: PMC5367080 DOI: 10.3389/fimmu.2017.00340] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 03/09/2017] [Indexed: 01/13/2023] Open
Abstract
Antigen processing for presentation by major histocompatibility complex class II (MHCII) molecules requires the latter to travel through the endocytic pathway together with its chaperons: the invariant chain (Ii) and DM. Nevertheless, the nature of the compartments where MHCII molecules travel to acquire peptides lacks definition regarding molecules involved in intracellular vesicular trafficking, such as Rab small GTPases. We aimed to define which Rab proteins are present during the intracellular transport of MHCII, DM, and Ii through the endocytic pathway on their route to the cell surface during dendritic cell (DC) maturation. We examined, by means of three-color confocal microscopy, the association of MHCII, DM, and Ii with Rab5, Rab7, Rab9, and Rab11 during the maturation of bone marrow-derived or spleen DC in response to LPS as an inflammatory stimulus. Prior to the stage of immature DC, MHCII migrated from diffuse small cytoplasmic vesicles, predominantly Rab5+Rab7- and Rab5+Rab7+ into a pericentriolar Rab5+Rab7+Rab9+ cluster, with Rab11+ areas. As DC reached the mature phenotype, MHCII left the pericentriolar endocytic compartments toward the cell surface in Rab11+ and Rab9+Rab11+ vesicles. The invariant chain and MHCII transport pathways were not identical. DM and MHCII appeared to arrive to pericentriolar endocytic compartments of immature DC through partially different routes. The association of MHCII molecules with distinct Rab GTPases during DC maturation suggests that after leaving the biosynthetic pathway, MHCII sequentially traffic from typical early endosomes to multivesicular late endosomes to finally arrive at the cell surface in Rab11+ recycling-type endosomes. In immature DCs, DM encounters transiently MHCII in the Rab5+Rab7+Rab9+ compartments, to remain there in mature DC.
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Affiliation(s)
- Gibrán Pérez-Montesinos
- Research Unit on Autoimmune Diseases, Research Unit on Immunochemistry, Centro México Nacional Siglo XXI, IMSS, Instituto Mexicano del Seguro Social, Mexico City, Distrito Federal, Mexico
- Centro Dermatológico “Dr. Ladislao de la Pascua”, Secretaría de Salud del Distrito Federal, Mexico City, Distrito Federal, Mexico
| | - Orestes López-Ortega
- Hospital Juárez de México, Secretaría de Salud, Mexico City, Distrito Federal, Mexico
| | - Jessica Piedra-Reyes
- Hospital Juárez de México, Secretaría de Salud, Mexico City, Distrito Federal, Mexico
| | - Laura C. Bonifaz
- Research Unit on Autoimmune Diseases, Research Unit on Immunochemistry, Centro México Nacional Siglo XXI, IMSS, Instituto Mexicano del Seguro Social, Mexico City, Distrito Federal, Mexico
| | - José Moreno
- Research Unit on Autoimmune Diseases, Research Unit on Immunochemistry, Centro México Nacional Siglo XXI, IMSS, Instituto Mexicano del Seguro Social, Mexico City, Distrito Federal, Mexico
- Hospital Juárez de México, Secretaría de Salud, Mexico City, Distrito Federal, Mexico
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Erazo-Oliveras A, Najjar K, Truong D, Wang TY, Brock DJ, Prater AR, Pellois JP. The Late Endosome and Its Lipid BMP Act as Gateways for Efficient Cytosolic Access of the Delivery Agent dfTAT and Its Macromolecular Cargos. Cell Chem Biol 2016; 23:598-607. [PMID: 27161484 DOI: 10.1016/j.chembiol.2016.03.016] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 03/16/2016] [Accepted: 03/22/2016] [Indexed: 01/02/2023]
Abstract
Endosomal entrapment is a severely limiting bottleneck in the delivery of biologics into cells. The compound dfTAT was recently found to circumvent this problem by mediating endosomal leakage efficiently and without toxicity. Herein, we report on the mechanism of endosomal escape of this cell-penetrating peptide. By modulating the trafficking of the peptide within the endocytic pathway, we identify late endosomes as the organelles rendered leaky by dfTAT. We establish that dfTAT binds bis(monoacylglycero)phosphate (BMP), a lipid found in late endosomes, and that the peptide causes the fusion and leakage of bilayers containing BMP. Together, these data identify late endosomes as desirable gateways for cell penetration and BMP as a cellular factor that can be exploited for the development of future delivery agents.
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Affiliation(s)
- Alfredo Erazo-Oliveras
- Department of Biochemistry and Biophysics, Texas A&M University, 300 Olsen Boulevard, College Station, TX 77843, USA
| | - Kristina Najjar
- Department of Biochemistry and Biophysics, Texas A&M University, 300 Olsen Boulevard, College Station, TX 77843, USA
| | - Dat Truong
- Department of Biochemistry and Biophysics, Texas A&M University, 300 Olsen Boulevard, College Station, TX 77843, USA
| | - Ting-Yi Wang
- Department of Biochemistry and Biophysics, Texas A&M University, 300 Olsen Boulevard, College Station, TX 77843, USA
| | - Dakota J Brock
- Department of Biochemistry and Biophysics, Texas A&M University, 300 Olsen Boulevard, College Station, TX 77843, USA
| | - Austin R Prater
- Department of Biochemistry and Biophysics, Texas A&M University, 300 Olsen Boulevard, College Station, TX 77843, USA
| | - Jean-Philippe Pellois
- Department of Biochemistry and Biophysics, Texas A&M University, 300 Olsen Boulevard, College Station, TX 77843, USA; Department of Chemistry, Texas A&M University, 300 Olsen Boulevard, College Station, TX 77843, USA.
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Huang Y, Ren Q. Identification and function of 11 Rab GTPases in giant freshwater prawn Macrobrachium rosenbergii. FISH & SHELLFISH IMMUNOLOGY 2015; 43:120-130. [PMID: 25542378 DOI: 10.1016/j.fsi.2014.12.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 12/15/2014] [Accepted: 12/16/2014] [Indexed: 06/04/2023]
Abstract
Rab GTPases, members of the Ras-like GTPase superfamily, are central elements in endocytic membrane trafficking. However, little is known of the Rab genes in the giant freshwater prawn Macrobrachium rosenbergii. In this study, 11 Rab genes were identified from M. rosenbergii. All MrRabs have a RAB domain. Phylogenetic analysis showed that these 11 MrRabs were divided into different groups. The MrRab genes were ubiquitously expressed in heart, hemocytes, hepatopancreas, gills, stomach, and intestines. Real-time polymerase chain reaction revealed that the MrRab genes were significantly upregulated by white spot syndrome virus (WSSV) in the prawns, indicating that MrRabs might play an important role in innate immune response against WSSV. Moreover, after challenge with Vibrio parahaemolyticus, the expression levels of all MrRabs in the hepatopancreas were also upregulated, which might indicated the involvement of MrRabs in prawns antibacterial immunity. In all, these preliminary results showed that MrRabs were involved in innate immunity of M. rosenbergii.
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Affiliation(s)
- Ying Huang
- Jiangsu Key Laboratory for Biodiversity & Biotechnology and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210046, PR China
| | - Qian Ren
- Jiangsu Key Laboratory for Biodiversity & Biotechnology and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210046, PR China.
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Park SW, Schonhoff CM, Webster CRL, Anwer MS. Rab11, but not Rab4, facilitates cyclic AMP- and tauroursodeoxycholate-induced MRP2 translocation to the plasma membrane. Am J Physiol Gastrointest Liver Physiol 2014; 307:G863-70. [PMID: 25190474 PMCID: PMC4200318 DOI: 10.1152/ajpgi.00457.2013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Rab proteins (Ras homologous for brain) play an important role in vesicle trafficking. Rab4 and Rab11 are involved in vesicular trafficking to the plasma membrane from early endosomes and recycling endosomes, respectively. Tauroursodeoxycholate (TUDC) and cAMP increase bile formation, in part, by increasing plasma membrane localization of multidrug resistance-associated protein 2 (MRP2). The goal of the present study was to determine the role of these Rab proteins in the trafficking of MRP2 by testing the hypothesis that Rab11 and/or Rab4 facilitate cAMP- and TUDC-induced MRP2 translocation to the plasma membrane. Studies were conducted in HuH-NTCP cells (HuH7 cells stably transfected with human NTCP), which constitutively express MRP2. HuH-NTCP cells were transfected with Rab11-WT and GDP-locked dominant inactive Rab11-GDP or with Rab4-GDP to study the role of Rab11 and Rab4. A biotinylation method and a GTP overlay assay were used to determine plasma membrane MRP2 and activation of Rab proteins (Rab11 and Rab4), respectively. Cyclic AMP and TUDC increased plasma membrane MRP2 and stimulated Rab11 activity. Plasma membrane translocation of MRP2 by cAMP and TUDC was increased and inhibited in cells transfected with Rab11-WT and Rab11-GDP, respectively. Cyclic AMP (previous study) and TUDC increased Rab4 activity. However, cAMP- and TUDC-induced increases in MRP2 were not inhibited by Rab4-GDP. Taken together, these results suggest that Rab11 is involved in cAMP- and TUDC-induced MRP2 translocation to the plasma membrane.
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Affiliation(s)
- Se Won Park
- Department of Biomedical Sciences, Cummings School of Veterinary Medicine at Tufts University, North Grafton, Massachusetts; and
| | - Christopher M Schonhoff
- Department of Biomedical Sciences, Cummings School of Veterinary Medicine at Tufts University, North Grafton, Massachusetts; and
| | - Cynthia R L Webster
- Department of Clinical Sciences, Cummings School of Veterinary Medicine at Tufts University, North Grafton, Massachusetts
| | - M Sawkat Anwer
- Department of Biomedical Sciences, Cummings School of Veterinary Medicine at Tufts University, North Grafton, Massachusetts; and
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Wang R, Zhang Y, Liu S, Li C, Sun L, Bao L, Feng J, Liu Z. Analysis of 52 Rab GTPases from channel catfish and their involvement in immune responses after bacterial infections. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2014; 45:21-34. [PMID: 24513270 DOI: 10.1016/j.dci.2014.01.026] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Revised: 01/31/2014] [Accepted: 01/31/2014] [Indexed: 06/03/2023]
Abstract
Rab genes, encoding a large family of monomeric G-proteins, contain over 60 members in the human genome. They have been recognized as crucial regulators for membrane trafficking including cargo sorting, vesicle formation, budding, motility, docking, fusion, secretory and endocytic pathway of host immune responses. However, little is known of the Rab gene family in teleost fish species. The development of full-length transcripts and whole genome sequences allow the identification and annotation of Rab GTPase gene family in catfish. In this study, a total of 52 Rab genes were identified from catfish cDNA and genome databases. Phylogenetic analysis assigned them into eleven subfamilies. Most Rab GTPases are conserved among vertebrates, though some of which are absent in fish genomes. Analysis of multiple RNA-seq datasets, along with real time PCR analysis revealed up-regulation of 10 Rab genes after bacterial infection. These included Rab3a, Rab4a, Rab4b, Rab5a, Rab5c, Rab7a, Rab9a, Rab11a, Rab11b, and Rab33a. Their up-regulation are temporally and spatially regulated in various tissues, but mostly induced at early stages after infection and in the gill and liver tissues, with the exception of Rab5c that is mostly up-regulated in the head kidney and trunk kidney. The complex pattern of their induced expression suggested both specific and cooperative actions of a these Rab genes in the acute immune responses to bacterial infection.
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Affiliation(s)
- Ruijia Wang
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, and Program of Cell and Molecular Biosciences, Auburn University, 203 Swingle Hall, Auburn, AL 36849, USA
| | - Yu Zhang
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, and Program of Cell and Molecular Biosciences, Auburn University, 203 Swingle Hall, Auburn, AL 36849, USA
| | - Shikai Liu
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, and Program of Cell and Molecular Biosciences, Auburn University, 203 Swingle Hall, Auburn, AL 36849, USA
| | - Chao Li
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, and Program of Cell and Molecular Biosciences, Auburn University, 203 Swingle Hall, Auburn, AL 36849, USA
| | - Luyang Sun
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, and Program of Cell and Molecular Biosciences, Auburn University, 203 Swingle Hall, Auburn, AL 36849, USA
| | - Lisui Bao
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, and Program of Cell and Molecular Biosciences, Auburn University, 203 Swingle Hall, Auburn, AL 36849, USA
| | - Jianbin Feng
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, and Program of Cell and Molecular Biosciences, Auburn University, 203 Swingle Hall, Auburn, AL 36849, USA
| | - Zhanjiang Liu
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, and Program of Cell and Molecular Biosciences, Auburn University, 203 Swingle Hall, Auburn, AL 36849, USA.
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Krai P, Dalal S, Klemba M. Evidence for a Golgi-to-endosome protein sorting pathway in Plasmodium falciparum. PLoS One 2014; 9:e89771. [PMID: 24587025 PMCID: PMC3934947 DOI: 10.1371/journal.pone.0089771] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 01/24/2014] [Indexed: 12/20/2022] Open
Abstract
During the asexual intraerythrocytic stage, the malaria parasite Plasmodium falciparum must traffic newly-synthesized proteins to a broad array of destinations within and beyond the parasite's plasma membrane. In this study, we have localized two well-conserved protein components of eukaryotic endosomes, the retromer complex and the small GTPase Rab7, to define a previously-undescribed endosomal compartment in P. falciparum. Retromer and Rab7 co-localized to a small number of punctate structures within parasites. These structures, which we refer to as endosomes, lie in close proximity to the Golgi apparatus and, like the Golgi apparatus, are inherited by daughter merozoites. However, the endosome is clearly distinct from the Golgi apparatus as neither retromer nor Rab7 redistributed to the endoplasmic reticulum upon brefeldin A treatment. Nascent rhoptries (specialized secretory organelles required for invasion) developed adjacent to endosomes, an observation that suggests a role for the endosome in rhoptry biogenesis. A P. falciparum homolog of the sortilin family of protein sorting receptors (PfSortilin) was localized to the Golgi apparatus. Together, these results elaborate a putative Golgi-to-endosome protein sorting pathway in asexual blood stage parasites and suggest that one role of retromer is to mediate the retrograde transport of PfSortilin from the endosome to the Golgi apparatus.
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Affiliation(s)
- Priscilla Krai
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Seema Dalal
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Michael Klemba
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia, United States of America
- * E-mail:
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Vigneron A, Charif D, Vincent-Monégat C, Vallier A, Gavory F, Wincker P, Heddi A. Host gene response to endosymbiont and pathogen in the cereal weevil Sitophilus oryzae. BMC Microbiol 2012; 12 Suppl 1:S14. [PMID: 22375912 PMCID: PMC3287511 DOI: 10.1186/1471-2180-12-s1-s14] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Background Insects thriving on nutritionally poor habitats have integrated mutualistic intracellular symbiotic bacteria (endosymbionts) in a bacteria-bearing tissue (the bacteriome) that isolates the endosymbionts and protects them against a host systemic immune response. Whilst the metabolic and physiological features of long-term insect associations have been investigated in detail over the past decades, cellular and immune regulations that determine the host response to endosymbionts and pathogens have attracted interest more recently. Results To investigate bacteriome cellular specificities and weevil immune responses to bacteria, we have constructed and sequenced 7 cDNA libraries from Sitophilus oryzae whole larvae and bacteriomes. Bioinformatic analysis of 26,886 ESTs led to the generation of 8,941 weevil unigenes. Based on in silico analysis and on the examination of genes involved in the cellular pathways of potential interest to intracellular symbiosis (i.e. cell growth and apoptosis, autophagy, immunity), we have selected and analyzed 29 genes using qRT-PCR, taking into consideration bacteriome specificity and symbiosis impact on the host response to pathogens. We show that the bacteriome tissue accumulates transcripts from genes involved in cellular development and survival, such as the apoptotic inhibitors iap2 and iap3, and endosomal fusion and trafficking, such as Rab7, Hrs, and SNARE. As regards our investigation into immunity, we first strengthen the bacteriome immunomodulation previously reported in S. zeamais. We show that the sarcotoxin, the c-type lysozyme, and the wpgrp2 genes are downregulated in the S. oryzae bacteriome, when compared to aposymbiotic insects and insects challenged with E. coli. Secondly, transcript level comparison between symbiotic and aposymbiotic larvae provides evidence that the immune systemic response to pathogens is decreased in symbiotic insects, as shown by the relatively high expression of wpgrp2, wpgrp3, coleoptericin-B, diptericin, and sarcotoxin genes in aposymbiotic insects. Conclusions Library sequencing significantly increased the number of unigenes, allowing for improved functional and genetic investigations in the cereal weevil S. oryzae. Transcriptomic analyses support selective and local immune gene expression in the bacteriome tissue and uncover cellular pathways that are of potential interest to bacteriocyte survival and homeostasis. Bacterial challenge experiments have revealed that the systemic immune response would be less induced in a symbiotic insect, thus highlighting new perspectives on host immunity in long-term invertebrate co-evolutionary associations.
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Zafar S, von Ahsen N, Oellerich M, Zerr I, Schulz-Schaeffer WJ, Armstrong VW, Asif AR. Proteomics Approach to Identify the Interacting Partners of Cellular Prion Protein and Characterization of Rab7a Interaction in Neuronal Cells. J Proteome Res 2011; 10:3123-35. [DOI: 10.1021/pr2001989] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Saima Zafar
- Department of Clinical Chemistry, ‡Department of Neurobiology, and §Department of Neuropathology, University Medical Center Goettingen (UMG), Robert-Koch-Strasse 40, 37075, Goettingen, Germany
| | - Nicolas von Ahsen
- Department of Clinical Chemistry, ‡Department of Neurobiology, and §Department of Neuropathology, University Medical Center Goettingen (UMG), Robert-Koch-Strasse 40, 37075, Goettingen, Germany
| | - Michael Oellerich
- Department of Clinical Chemistry, ‡Department of Neurobiology, and §Department of Neuropathology, University Medical Center Goettingen (UMG), Robert-Koch-Strasse 40, 37075, Goettingen, Germany
| | - Inga Zerr
- Department of Clinical Chemistry, ‡Department of Neurobiology, and §Department of Neuropathology, University Medical Center Goettingen (UMG), Robert-Koch-Strasse 40, 37075, Goettingen, Germany
| | - Walter J. Schulz-Schaeffer
- Department of Clinical Chemistry, ‡Department of Neurobiology, and §Department of Neuropathology, University Medical Center Goettingen (UMG), Robert-Koch-Strasse 40, 37075, Goettingen, Germany
| | - Victor W. Armstrong
- Department of Clinical Chemistry, ‡Department of Neurobiology, and §Department of Neuropathology, University Medical Center Goettingen (UMG), Robert-Koch-Strasse 40, 37075, Goettingen, Germany
| | - Abdul R. Asif
- Department of Clinical Chemistry, ‡Department of Neurobiology, and §Department of Neuropathology, University Medical Center Goettingen (UMG), Robert-Koch-Strasse 40, 37075, Goettingen, Germany
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BasuRay S, Mukherjee S, Romero E, Wilson MC, Wandinger-Ness A. Rab7 mutants associated with Charcot-Marie-Tooth disease exhibit enhanced NGF-stimulated signaling. PLoS One 2010; 5:e15351. [PMID: 21151572 PMCID: PMC3000344 DOI: 10.1371/journal.pone.0015351] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Accepted: 11/11/2010] [Indexed: 11/30/2022] Open
Abstract
Missense mutants in the late endosomal Rab7 GTPase cause the autosomal dominant peripheral neuropathy Charcot-Marie-Tooth disease type 2B (CMT2B). As yet, the pathological mechanisms connecting mutant Rab7 protein expression to altered neuronal function are undefined. Here, we analyze the effects Rab7 CMT2B mutants on nerve growth factor (NGF) dependent intracellular signaling in PC12 cells. The nerve growth factor receptor TrkA interacted similarly with Rab7 wild-type and CMT2B mutant proteins, but the mutant proteins significantly enhanced TrkA phosphorylation in response to brief NGF stimulation. Two downstream signaling pathways (Erk1/2 and Akt) that are directly activated in response to phospho-TrkA were differentially affected. Akt signaling, arising in response to activated TrkA at the plasma membrane was unaffected. However Erk1/2 phosphorylation, triggered on signaling endosomes, was increased. Cytoplasmic phospho-Erk1/2 persisted at elevated levels relative to control samples for up to 24 h following NGF stimulation. Nuclear shuttling of phospho Erk1/2, which is required to induce MAPK phosphatase expression and down regulate signaling, was greatly reduced by the Rab7 CMT2B mutants and explains the previously reported inhibition in PC12 neurite outgrowth. In conclusion, the data demonstrate a mechanistic link between Rab7 CMT2B mutants and altered TrkA and Erk1/2 signaling from endosomes.
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Affiliation(s)
- Soumik BasuRay
- Department of Pathology and Cancer Research and Treatment Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States of America
| | - Sanchita Mukherjee
- Department of Pathology and Cancer Research and Treatment Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States of America
| | - Elsa Romero
- Department of Pathology and Cancer Research and Treatment Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States of America
| | - Michael C. Wilson
- Department of Neurosciences, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States of America
| | - Angela Wandinger-Ness
- Department of Pathology and Cancer Research and Treatment Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States of America
- * E-mail:
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Mackiewicz P, Wyroba E. Phylogeny and evolution of Rab7 and Rab9 proteins. BMC Evol Biol 2009; 9:101. [PMID: 19442299 PMCID: PMC2693434 DOI: 10.1186/1471-2148-9-101] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Accepted: 05/14/2009] [Indexed: 11/14/2022] Open
Abstract
Background An important role in the evolution of intracellular trafficking machinery in eukaryotes played small GTPases belonging to the Rab family known as pivotal regulators of vesicle docking, fusion and transport. The Rab family is very diversified and divided into several specialized subfamilies. We focused on the VII functional group comprising Rab7 and Rab9, two related subfamilies, and analysed 210 sequences of these proteins. Rab7 regulates traffic from early to late endosomes and from late endosome to vacuole/lysosome, whereas Rab9 participates in transport from late endosomes to the trans-Golgi network. Results Although Rab7 and Rab9 proteins are quite small and show heterogeneous rates of substitution in different lineages, we found a phylogenetic signal and inferred evolutionary relationships between them. Rab7 proteins evolved before radiation of main eukaryotic supergroups while Rab9 GTPases diverged from Rab7 before split of choanoflagellates and metazoans. Additional duplication of Rab9 and Rab7 proteins resulting in several isoforms occurred in the early evolution of vertebrates and next in teleost fishes and tetrapods. Three Rab7 lineages emerged before divergence of monocots and eudicots and subsequent duplications of Rab7 genes occurred in particular angiosperm clades. Interestingly, several Rab7 copies were identified in some representatives of excavates, ciliates and amoebozoans. The presence of many Rab copies is correlated with significant differences in their expression level. The diversification of analysed Rab subfamilies is also manifested by non-conserved sequences and structural features, many of which are involved in the interaction with regulators and effectors. Individual sites discriminating different subgroups of Rab7 and Rab9 GTPases have been identified.
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Affiliation(s)
- Paweł Mackiewicz
- University of Wrocław, Faculty of Biotechnology, Department of Genomics, 63/77 Przybyszewskiego Street, 51-148 Wrocław, Poland.
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14
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Mountjoy JR, Xu W, McLeod D, Hyndman D, Oko R. RAB2A: A Major Subacrosomal Protein of Bovine Spermatozoa Implicated in Acrosomal Biogenesis1. Biol Reprod 2008; 79:223-32. [DOI: 10.1095/biolreprod.107.065060] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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15
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Caveolin-1-dependent infectious entry of human papillomavirus type 31 in human keratinocytes proceeds to the endosomal pathway for pH-dependent uncoating. J Virol 2008; 82:9505-12. [PMID: 18667513 DOI: 10.1128/jvi.01014-08] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
High-risk human papillomaviruses (HPVs) are small nonenveloped DNA viruses with a strict tropism for squamous epithelium. The viruses are causative agents of cervical cancer and some head and neck cancers, but their differentiation-dependent life cycles have made them difficult to study in simple cell culture. Thus, many aspects of early HPV infection remain mysterious. We recently showed the high-risk HPV type 31 (HPV31) enters its natural host cell type via caveola-dependent endocytosis, a distinct mechanism from that of the closely related HPV16 (Smith et al., J. Virol. 81:9922-9931, 2007). Here, we determined the downstream trafficking events after caveolar entry of HPV31 into human keratinocytes. After initial plasma membrane binding, HPV31 associates with caveolin-1 and transiently localizes to the caveosome before trafficking to the early endosome and proceeding through the endosomal pathway. Caveosome-to-endosome transport was found to be Rab5 GTPase dependent. Although HPV31 capsids were observed in the lysosome, Rab7 GTPase was dispensable for HPV31 infection, suggesting that viral genomes escape from the endosomal pathway prior to Rab7-mediated capsid transport. Consistent with this, the acidic pH encountered by HPV31 within the early endosomal pathway induces a conformational change in the capsid resulting in increased DNase susceptibility of the viral genome, which likely aids in uncoating and/or endosomal escape. The entry and trafficking route of HPV31 into human keratinocytes represents a unique viral pathway by which the virions use caveolar entry to eventually access a low-pH site that appears to facilitate endosomal escape of genomes.
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16
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Cao C, Backer JM, Laporte J, Bedrick EJ, Wandinger-Ness A. Sequential actions of myotubularin lipid phosphatases regulate endosomal PI(3)P and growth factor receptor trafficking. Mol Biol Cell 2008; 19:3334-46. [PMID: 18524850 DOI: 10.1091/mbc.e08-04-0367] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Two different human diseases, X-linked myotubular myopathy and Charcot-Marie-Tooth disease, result from mutant MTM1 or MTMR2 lipid phosphatases. Although events involved in endosomal PI(3)P and PI(3,5)P(2) synthesis are well established and pivotal in receptor signaling and degradation, enzymes involved in phosphoinositide degradation and their roles in trafficking are incompletely characterized. Here, we dissect the functions of the MTM1 and MTMR2 myotubularins and establish how they contribute to endosomal PI(3)P homeostasis. By mimicking loss of function in disease through siRNA-mediated depletion of the myotubularins, excess PI(3)P accumulates on early (MTM1) and late (MTMR2) endosomes. Surprisingly, the increased PI(3)P blocks the egress of epidermal growth factor receptors from early or late endosomes, suggesting that the accumulation of signaling receptors in distinct endosomes may contribute to the unique disease etiologies when MTM1 or MTMR2 are mutant. We further demonstrate that direct myotubularin binding to the type III PI 3-kinase complex hVps34/hVps15 leads to phosphatase inactivation. The lipid kinase-phosphatase interaction also precludes interaction of the PI 3-kinase with Rab GTPase activators. Thus, unique molecular complexes control kinase and phosphatase activation and locally regulate PI(3)P on discrete endosome populations, thereby providing a molecular rationale for related human myo- and neuropathies.
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Affiliation(s)
- Canhong Cao
- Department of Pathology, University of New Mexico School of Medicine, Albuquerque, NM 87131, USA
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17
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Schwartz SL, Cao C, Pylypenko O, Rak A, Wandinger-Ness A. Rab GTPases at a glance. J Cell Sci 2008; 120:3905-10. [PMID: 17989088 DOI: 10.1242/jcs.015909] [Citation(s) in RCA: 329] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Samantha L Schwartz
- Department of Pathology MSC08-4640, University of New Mexico, 2325 Camino de Salud NE, CRF225, Albuquerque, NM 87131, USA
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18
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Colpitts TM, Moore AC, Kolokoltsov AA, Davey RA. Venezuelan equine encephalitis virus infection of mosquito cells requires acidification as well as mosquito homologs of the endocytic proteins Rab5 and Rab7. Virology 2007; 369:78-91. [PMID: 17707875 PMCID: PMC2464296 DOI: 10.1016/j.virol.2007.07.012] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2007] [Revised: 05/07/2007] [Accepted: 07/09/2007] [Indexed: 11/18/2022]
Abstract
Venezuelan equine encephalitis virus (VEEV) is a New World alphavirus that can cause fatal encephalitis in humans. It remains a naturally emerging disease as well as a highly developed biological weapon. VEEV is transmitted to humans in nature by mosquito vectors. Little is known about VEEV entry, especially in mosquito cells. Here, a novel luciferase-based virus entry assay is used to show that the entry of VEEV into mosquito cells requires acidification. Furthermore, mosquito homologs of key human proteins (Rab5 and Rab7) involved in endocytosis were isolated and characterized. Rab5 is found on early endosomes and Rab7 on late endosomes and both are important for VEEV entry in mammalian cells. Each was shown to have analogous function in mosquito cells to that seen in mammalian cells. The wild-type, dominant negative and constitutively active mutants were then used to demonstrate that VEEV requires passage through early and late endosomes before infection can take place. This work indicates that the infection mechanism in mosquitoes and mammals is through a common and ancient evolutionarily conserved pathway.
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Affiliation(s)
| | | | | | - Robert A. Davey
- Corresponding author: Robert Davey, Department of Microbiology and Immunology, University of Texas Medical Branch, 301 University Blvd, Galveston, Texas, USA. Telephone: 409 772 4915, Fax: 409 772 5065,
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19
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Ganley IG, Pfeffer SR. Cholesterol accumulation sequesters Rab9 and disrupts late endosome function in NPC1-deficient cells. J Biol Chem 2006; 281:17890-9. [PMID: 16644737 PMCID: PMC3650718 DOI: 10.1074/jbc.m601679200] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Niemann-Pick type C disease is an autosomal recessive disorder that leads to massive accumulation of cholesterol and glycosphingolipids in late endosomes and lysosomes. To understand how cholesterol accumulation influences late endosome function, we investigated the effect of elevated cholesterol on Rab9-dependent export of mannose 6-phosphate receptors from this compartment. Endogenous Rab9 levels were elevated 1.8-fold in Niemann-Pick type C cells relative to wild type cells, and its half-life increased 1.6-fold, suggesting that Rab9 accumulation is caused by impaired protein turnover. Reduced Rab9 degradation was accompanied by stabilization on endosome membranes, as shown by a reduction in the capacity of Rab9 for guanine nucleotide dissociation inhibitor-mediated extraction from Niemann-Pick type C membranes. Cholesterol appeared to stabilize Rab9 directly, as liposomes loaded with prenylated Rab9 showed decreased extractability with increasing cholesterol content. Rab9 is likely sequestered in an inactive form on Niemann-Pick type C membranes, as cation-dependent mannose 6-phosphate receptors were missorted to the lysosome for degradation, a process that was reversed by overexpression of GFP-tagged Rab9. In addition to using primary fibroblasts isolated from Niemann-Pick type C patients, RNA interference was utilized to recapitulate the disease phenotype in cultured cells, greatly facilitating the analysis of cholesterol accumulation and late endosome function. We conclude that cholesterol contributes directly to the sequestration of Rab9 on Niemann-Pick type C cell membranes, which in turn, disrupts mannose 6-phosphate receptor trafficking.
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Affiliation(s)
- Ian G. Ganley
- the Department of Biochemistry, Stanford University School of Medicine, Stanford, California 94305-5307
| | - Suzanne R. Pfeffer
- the Department of Biochemistry, Stanford University School of Medicine, Stanford, California 94305-5307
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20
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Kolokoltsov AA, Fleming EH, Davey RA. Venezuelan equine encephalitis virus entry mechanism requires late endosome formation and resists cell membrane cholesterol depletion. Virology 2006; 347:333-42. [PMID: 16427678 DOI: 10.1016/j.virol.2005.11.051] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2005] [Revised: 09/27/2005] [Accepted: 11/30/2005] [Indexed: 10/25/2022]
Abstract
Virus envelope proteins determine receptor utilization and host range. The choice of receptor not only permits specific targeting of cells that express it, but also directs the virus into specific endosomal trafficking pathways. Disrupting trafficking can result in loss of virus infectivity due to redirection of virions to non-productive pathways. Identification of the pathway or pathways used by a virus is, thus, important in understanding virus pathogenesis mechanisms and for developing new treatment strategies. Most of our understanding of alphavirus entry has focused on the Old World alphaviruses, such as Sindbis and Semliki Forest virus. In comparison, very little is known about the entry route taken by more pathogenic New World alphaviruses. Here, we use a novel contents mixing assay to identify the cellular requirements for entry of a New World alphavirus, Venezuelan equine encephalitis virus (VEEV). Expression of dominant negative forms of key endosomal trafficking genes shows that VEEV must access clathrin-dependent endocytic vesicles for membrane fusion to occur. Unexpectedly, the exit point is different from Old World alphaviruses that leave from early endosomes. Instead, VEEV also requires functional late endosomes. Furthermore, unlike the Old World viruses, VEEV entry is insensitive to cholesterol sequestration from cell membranes and may reflect a need to access an endocytic compartment that lacks cholesterol. This indicates fundamental differences in the entry route taken by VEEV compared to Old World alphaviruses.
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Affiliation(s)
- Andrey A Kolokoltsov
- Department of Microbiology and Immunology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
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21
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Stein MP, Cao C, Tessema M, Feng Y, Romero E, Welford A, Wandinger-Ness A. Interaction and functional analyses of human VPS34/p150 phosphatidylinositol 3-kinase complex with Rab7. Methods Enzymol 2005; 403:628-49. [PMID: 16473626 DOI: 10.1016/s0076-6879(05)03055-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The Rab7 GTPase is a key regulator of late endocytic membrane transport and autophagy. Rab7 exerts temporal and spatial control over late endocytic membrane transport through interactions with various effector proteins. Among Rab7 effectors, the hVPS34/p150 phosphatidylinositol (PtdIns) 3-kinase complex serves to regulate late endosomal phosphatidylinositol signaling that is important for protein sorting and intraluminal vesicle sequestration. In this chapter, reagents and methods for the characterization of the interactions and regulation of the Rab7/hVPS34/p150 complex are described. Using these methods we demonstrate the requirement for activated Rab7 in the regulation of hVPS34/p150 PtdIns 3-kinase activity on late endosomes in vivo.
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22
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Dong J, Chen W, Welford A, Wandinger-Ness A. The proteasome alpha-subunit XAPC7 interacts specifically with Rab7 and late endosomes. J Biol Chem 2004; 279:21334-42. [PMID: 14998988 DOI: 10.1074/jbc.m401022200] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Rab7 is a key regulatory protein governing early to late endocytic membrane transport. In this study the proteasome alpha-subunit XAPC7 (also known as PSMA7, RC6-1, and HSPC in mammals) was identified to interact specifically with Rab7 and was recruited to multivesicular late endosomes through this interaction. The protein interaction domains were localized to the C terminus of XAPC7 and the N terminus of Rab7. XAPC7 was not found on early or recycling endosomes, but could be recruited to recycling endosomes by expression of a Rab7-(1-174)Rab11-(160-202) chimera, establishing a central role for Rab7 in the membrane recruitment of XAPC7. Although XAPC7 could be shown to associate with membranes bearing ubiquitinated cargo, overexpression had no impact on steady-state ubiquitinated protein levels. Most notably, overexpression of XAPC7 was found to impair late endocytic transport of two different membrane proteins, including EGFR known to be highly dependent on ubiquitination and proteasome activity for proper endocytic sorting and lysosomal transport. Decreased late endocytic transport caused by XAPC7 overexpression was partially rescued by coexpression of wild-type Rab7, suggesting a negative regulatory role for XAPC7. Nevertheless, Rab7 itself was not subject to XAPC7-dependent proteasomal degradation. Together the data establish the first direct molecular link between the endocytic trafficking and cytosolic degradative machineries.
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Affiliation(s)
- Jianbo Dong
- Molecular Trafficking Laboratory, Department of Pathology, University of New Mexico School of Medicine, 2325 Camino del Salud NE, Albuquerque, NM 87131, USA
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23
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Li Y, Wandinger-Ness A, Goldenring JR, Cover TL. Clustering and redistribution of late endocytic compartments in response to Helicobacter pylori vacuolating toxin. Mol Biol Cell 2004; 15:1946-59. [PMID: 14742715 PMCID: PMC379289 DOI: 10.1091/mbc.e03-08-0618] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Helicobacter pylori VacA is a secreted protein toxin that may contribute to the pathogenesis of peptic ulcer disease and gastric adenocarcinoma. When added to cultured mammalian cells in the presence of weak bases (e.g., ammonium chloride), VacA induces the formation of large cytoplasmic vacuoles. Here, we report a previously unrecognized capacity of VacA to induce clustering and perinuclear redistribution of late endocytic compartments. In contrast to VacA-induced cell vacuolation, VacA-induced clustering and redistribution of late endocytic compartments are not dependent on the presence of weak bases and are not inhibited by bafilomycin A1. VacA mutant toxins defective in the capacity to form anion-selective membrane channels fail to cause clustering and redistribution. VacA-induced clusters of late endocytic compartments undergo transformation into vacuoles after the addition of ammonium chloride. VacA-induced clustering and redistribution of late endocytic compartments occur in cells expressing wild-type or constitutively active Rab7, but not in cells expressing dominant-negative mutant Rab7. In VacA-treated cells containing clustered late endocytic compartments, overexpression of dominant-negative Rab7 causes reversion to a nonclustered distribution. Redistribution of late endocytic compartments to the perinuclear region requires a functional microtubule cytoskeleton, whereas clustering of these compartments and vacuole formation do not. These data provide evidence that clustering of late endocytic compartments is a critical mechanistic step in the process of VacA-induced cell vacuolation. We speculate that VacA-induced alterations in late endocytic membrane traffic contribute to the capacity of H. pylori to persistently colonize the human gastric mucosa.
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Affiliation(s)
- Yi Li
- Department of Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
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24
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Henry RM, Hoppe AD, Joshi N, Swanson JA. The uniformity of phagosome maturation in macrophages. J Cell Biol 2004; 164:185-94. [PMID: 14718518 PMCID: PMC2172341 DOI: 10.1083/jcb.200307080] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2003] [Accepted: 11/25/2003] [Indexed: 01/22/2023] Open
Abstract
Many studies of endocytosis and phagocytosis presume that organelles containing a single kind of internalized particle exhibit invariant patterns of protein and phospholipid association as they mature inside cells. To test this presumption, fluorescent protein chimeras were expressed in RAW 264.7 macrophages, and time-lapse ratiometric fluorescence microscopy was used to measure the maturation dynamics of individual phagosomes containing IgG-opsonized erythrocytes. Quantitative analysis revealed consistent patterns of association for YFP chimeras of beta-actin, Rab5a, Rab7, and LAMP-1, and no association of YFP chimeras marking endoplasmic reticulum or Golgi. YFP-2xFYVE, recognizing phosphatidylinositol 3-phosphate (PI(3)P), showed two patterns of phagosome labeling. Some phagosomes increased labeling quickly after phagosome closure and then lost the label within 20 min, whereas others labeled more slowly and retained the label for several hours. The two patterns of PI(3)P on otherwise identical phagosomes indicated that organelle maturation does not necessarily follow a single path and that some features of phagosome maturation are integrated over the entire organelle.
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Affiliation(s)
- Rebecca M Henry
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109-0620, USA
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25
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Rzomp KA, Scholtes LD, Briggs BJ, Whittaker GR, Scidmore MA. Rab GTPases are recruited to chlamydial inclusions in both a species-dependent and species-independent manner. Infect Immun 2003; 71:5855-70. [PMID: 14500507 PMCID: PMC201052 DOI: 10.1128/iai.71.10.5855-5870.2003] [Citation(s) in RCA: 181] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Chlamydiae are obligate intracellular bacteria that replicate within an inclusion that is trafficked to the peri-Golgi region where it fuses with exocytic vesicles. The host and chlamydial proteins that regulate the trafficking of the inclusion have not been identified. Since Rab GTPases are key regulators of membrane trafficking, we examined the intracellular localization of several green fluorescent protein (GFP)-tagged Rab GTPases in chlamydia-infected HeLa cells. GFP-Rab4 and GFP-Rab11, which function in receptor recycling, and GFP-Rab1, which functions in endoplasmic reticulum (ER)-to-Golgi trafficking, are recruited to Chlamydia trachomatis, Chlamydia muridarum, and Chlamydia pneumoniae inclusions, whereas GFP-Rab5, GFP-Rab7, and GFP-Rab9, markers of early and late endosomes, are not. In contrast, GFP-Rab6, which functions in Golgi-to-ER and endosome-to-Golgi trafficking, is associated with C. trachomatis inclusions but not with C. pneumoniae or C. muridarum inclusions, while the opposite was observed for the Golgi-localized GFP-Rab10. Colocalization studies between transferrin and GFP-Rab11 demonstrate that a portion of GFP-Rab11 that localizes to inclusions does not colocalize with transferrin, which suggests that GFP-Rab11's association with the inclusion is not mediated solely through Rab11's association with transferrin-containing recycling endosomes. Finally, GFP-Rab GTPases remain associated with the inclusion even after disassembly of microtubules, which disperses recycling endosomes and the Golgi apparatus within the cytoplasm, suggesting a specific interaction with the inclusion membrane. Consistent with this, GFP-Rab11 colocalizes with C. trachomatis IncG at the inclusion membrane. Therefore, chlamydiae recruit key regulators of membrane trafficking to the inclusion, which may function to regulate the trafficking or fusogenic properties of the inclusion.
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Affiliation(s)
- Kimberly A Rzomp
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
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Brumell JH, Kujat-Choy S, Brown NF, Vallance BA, Knodler LA, Finlay BB. SopD2 is a novel type III secreted effector of Salmonella typhimurium that targets late endocytic compartments upon delivery into host cells. Traffic 2003; 4:36-48. [PMID: 12535274 DOI: 10.1034/j.1600-0854.2003.40106.x] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Salmonella typhimuriumis a facultative intracellular pathogen that utilizes two type III secretion systems to deliver virulence proteins into host cells. These proteins, termed effectors, alter host cell function to allow invasion into and intracellular survival/replication within a vacuolar compartment. Here we describe SopD2, a novel member of the Salmonella translocated effector (STE) family, which share a conserved N-terminal type III secretion signal. Disruption of the sopD2 gene prolonged the survival of mice infected with a lethal dose of Salmonella typhimurium, demonstrating a significant role for this effector in pathogenesis. Expression of sopD2 was induced inside host cells and was dependent on functional ssrA/B and phoP/Q, two component regulatory systems. HA-tagged SopD2 was delivered into HeLa cells in a SPI-2-dependent manner and associated with both the Salmonella-containing vacuole and with swollen endosomes elsewhere in the cell. Subcellular fractionation confirmed that SopD2 was membrane associated in host cells, while the closely related effector SopD was localized to the cytosol. A SopD2 fusion to GFP associated with small tubular structures and large vesicles containing late endocytic markers, including Rab7. Surprisingly, expression of N-terminal amino acids 1-150 of SopD2 fused to GFP was sufficient to mediate both binding to late endosomes/lysosomes and swelling of these compartments. These findings demonstrate that the N-terminus of SopD2 is a bifunctional domain required for both type III secretion out of Salmonella as well as late endosome/lysosome targeting following translocation into host cells.
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Affiliation(s)
- John H Brumell
- Biotechnology Laboratory and Departments of Biochemistry and Molecular Biology, Microbiology and Immunology, University of British Columbia, Vancouver, BC, V6T-1Z3, Canada
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Hölttä-Vuori M, Tanhuanpää K, Möbius W, Somerharju P, Ikonen E. Modulation of cellular cholesterol transport and homeostasis by Rab11. Mol Biol Cell 2002; 13:3107-22. [PMID: 12221119 PMCID: PMC124146 DOI: 10.1091/mbc.e02-01-0025] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
To analyze the contribution of vesicular trafficking pathways in cellular cholesterol transport we examined the effects of selected endosomal Rab proteins on cholesterol distribution by filipin staining. Transient overexpression of Rab11 resulted in prominent accumulation of free cholesterol in Rab11-positive organelles that sequestered transferrin receptors and internalized transferrin. Sphingolipids were selectively redistributed as pyrene-sphingomyelin and sulfatide cosequestered with Rab11-positive endosomes, whereas globotriaosyl ceramide and GM2 ganglioside did not. Rab11 overexpression did not perturb the transport of 1,1'-dioctadecyl-3,3,3',3'-tetramethyl-indocarbocyanine-perchlorate-labeled low-density lipoprotein (LDL) to late endosomes or the Niemann-Pick type C1 (NPC1)-induced late endosomal cholesterol clearance in NPC patient cells. However, Rab11 overexpression inhibited cellular cholesterol esterification in an LDL-independent manner. This effect could be overcome by introducing cholesterol to the plasma membrane by using cyclodextrin as a carrier. These results suggest that in Rab11-overexpressing cells, deposition of cholesterol in recycling endosomes results in its impaired esterification, presumably due to defective recycling of cholesterol to the plasma membrane. The findings point to the importance of the recycling endosomes in regulating cholesterol and sphingolipid trafficking and cellular cholesterol homeostasis.
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Affiliation(s)
- Maarit Hölttä-Vuori
- Department of Molecular Medicine, National Public Health Institute, Biomedicum Helsinki, Finland
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