1
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Huang L, Thiex NW, Lou J, Ahmad G, An W, Low-Nam ST, Kerkvliet JG, Band H, Hoppe AD. The ubiquitin ligases Cbl and Cbl-b regulate macrophage growth by controlling CSF-1R import into macropinosomes. Mol Biol Cell 2024; 35:ar38. [PMID: 38170572 PMCID: PMC10916879 DOI: 10.1091/mbc.e23-09-0345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 12/11/2023] [Accepted: 12/18/2023] [Indexed: 01/05/2024] Open
Abstract
The ubiquitination of transmembrane receptors regulates endocytosis, intracellular traffic, and signal transduction. Bone marrow-derived macrophages from myeloid Cbl-/- and Cbl-b-/- double knockout (DKO) mice display sustained proliferation mirroring the myeloproliferative disease that these mice succumb to. Here, we found that the ubiquitin ligases Cbl and Cbl-b have overlapping functions for controlling the endocytosis and intracellular traffic of the CSF-1R. DKO macrophages displayed complete loss of ubiquitination of the CSF-1R whereas partial ubiquitination was observed for either single Cbl-/- or Cbl-b-/- macrophages. Unlike wild type, DKO macrophages were immortal and displayed slower CSF-1R internalization, elevated AKT signaling, and a failure to transport the CSF-1R into the lumen of nascent macropinosomes, leaving its cytoplasmic region available for signaling. CSF-1R degradation depended upon lysosomal vATPase activity in both WT and DKO macrophages, with this degradation confined to macropinosomes in WT but occurring in distributed/tubular lysosomes in DKO cells. RNA-sequencing comparison of Cbl-/-, Cbl-b-/- and DKO macrophages indicated that while the overall macrophage transcriptional program remained intact, DKO macrophages had alterations in gene expression associated with growth factor signaling, cell cycle, inflammation and senescence. Cbl-b-/- had minimal effect on the transcriptional program whereas Cbl-/- led to more alternations but only DKO macrophages demonstrated substantial changes in the transcriptome, suggesting overlapping but unique functions for the two Cbl-family members. Thus, Cbl/Cbl-b-mediated ubiquitination of CSF-1R regulates its endocytic fate, constrains inflammatory gene expression, and regulates signaling for macrophage proliferation.
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Affiliation(s)
- Lu Huang
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD 57007
- BioSNTR, Brookings, SD 57007
| | - Natalie W. Thiex
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007
- BioSNTR, Brookings, SD 57007
| | - Jieqiong Lou
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD 57007
| | - Gulzar Ahmad
- Eppley Institute for Research in Cancer and Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198
| | - Wei An
- Eppley Institute for Research in Cancer and Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198
| | - Shalini T. Low-Nam
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD 57007
| | - Jason G. Kerkvliet
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD 57007
- BioSNTR, Brookings, SD 57007
| | - Hamid Band
- Eppley Institute for Research in Cancer and Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198
| | - Adam D. Hoppe
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD 57007
- BioSNTR, Brookings, SD 57007
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2
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Jo S, Fischer BR, Cronin NM, Nurmalasari NPD, Loyd YM, Kerkvliet JG, Bailey EM, Anderson RB, Scott BL, Hoppe AD. Antibody surface mobility amplifies FcγR signaling via Arp2/3 during phagocytosis. Biophys J 2024:S0006-3495(24)00094-8. [PMID: 38321740 DOI: 10.1016/j.bpj.2024.01.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 11/07/2023] [Accepted: 01/29/2024] [Indexed: 02/08/2024] Open
Abstract
We report herein that the anti-CD20 therapeutic antibody, rituximab, is rearranged into microclusters within the phagocytic synapse by macrophage Fcγ receptors (FcγR) during antibody-dependent cellular phagocytosis. These microclusters were observed to potently recruit Syk and to undergo rearrangements that were limited by the cytoskeleton of the target cell, with depolymerization of target-cell actin filaments leading to modest increases in phagocytic efficiency. Total internal reflection fluorescence analysis revealed that FcγR total phosphorylation, Syk phosphorylation, and Syk recruitment were enhanced when IgG-FcγR microclustering was enabled on fluid bilayers relative to immobile bilayers in a process that required Arp2/3. We conclude that on fluid surfaces, IgG-FcγR microclustering promotes signaling through Syk that is amplified by Arp2/3-driven actin rearrangements. Thus, the surface mobility of antigens bound by IgG shapes the signaling of FcγR with an unrecognized complexity beyond the zipper and trigger models of phagocytosis.
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Affiliation(s)
- Seongwan Jo
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, South Dakota; BioSNTRii, South Dakota State University, Brookings, South Dakota
| | - Brady R Fischer
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, South Dakota; BioSNTRii, South Dakota State University, Brookings, South Dakota
| | - Nicholas M Cronin
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, South Dakota; BioSNTRii, South Dakota State University, Brookings, South Dakota
| | - Ni Putu Dewi Nurmalasari
- Department of Nanoscience & Biomedical Engineering, South Dakota School of Mines and Technology, Rapid City, South Dakota; BioSNTRii, South Dakota School of Mines and Technology, Rapid City, South Dakota
| | - Yoseph M Loyd
- Department of Nanoscience & Biomedical Engineering, South Dakota School of Mines and Technology, Rapid City, South Dakota; BioSNTRii, South Dakota School of Mines and Technology, Rapid City, South Dakota
| | - Jason G Kerkvliet
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, South Dakota; BioSNTRii, South Dakota State University, Brookings, South Dakota
| | - Elizabeth M Bailey
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, South Dakota; BioSNTRii, South Dakota State University, Brookings, South Dakota
| | - Robert B Anderson
- Department of Nanoscience & Biomedical Engineering, South Dakota School of Mines and Technology, Rapid City, South Dakota; BioSNTRii, South Dakota School of Mines and Technology, Rapid City, South Dakota
| | - Brandon L Scott
- Department of Nanoscience & Biomedical Engineering, South Dakota School of Mines and Technology, Rapid City, South Dakota; BioSNTRii, South Dakota School of Mines and Technology, Rapid City, South Dakota
| | - Adam D Hoppe
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, South Dakota; BioSNTRii, South Dakota State University, Brookings, South Dakota.
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3
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Hossain MS, Kerkvliet JG, Hoppe AD. Whole genome CRISPR screening strategy to identify genes contributing to SARS-CoV-2 spike and VSV-G mediated entry. J Med Virol 2023; 95:e29087. [PMID: 37707319 DOI: 10.1002/jmv.29087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 08/29/2023] [Accepted: 08/31/2023] [Indexed: 09/15/2023]
Abstract
Understanding the cellular host factors that promote and inhibit viral entry is important for identifying viral countermeasures. CRISPR whole-genome screens can be used to rapidly discover host factors that contribute to or impair viral entry. However, when using live viruses and cellular lethality for selection, these screens can identify an overwhelming number of genes without specificity for the stage of the viral infection cycle. New screening methods are needed to identify host machinery contributing to specific steps of viral infection. Here, we developed a CRISPR whole-genome screen and counter-screen strategy based on a pseudoviral platform that allowed identification of genes specific to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike and vesicular stomatitis virus glycoprotein (VSV-G) mediated entry. Screening of SARS-CoV-2 spike and VSV-G on the same lentiviral pseudovirus allowed the identification of entry-specific genes relative to genes associated with retro-transcription, integration, and reporter expression from the lentiviral pseudovirus. Second, a Cre-Gag fusion protein packaged into the pseudovirus was used to bypass retro-transcription and integration by directly activating a floxed fluorescent protein reporter upon entry reduced the number of gene hits and increase specificity for viral entry. Our approach correctly identified SARS-CoV-2 and VSV-G receptors ACE2 and low-density lipoprotein receptors, respectively, and distinguished genes associated with retroviral reporter expression from envelope-mediated entry. Moreover, the CRE-Gag fusion/flox reporter increased the screen specificity for viral entry-associated genes. Validation of a few hits demonstrates that this approach distinguishes envelope-specific host factors from genes affecting reporter expression. Overall, this approach provides a new strategy for identifying host genes influencing viral entry without the confounding complexity of live-viral screens which produce long gene lists associated with all aspects of viral pathogenesis and replication.
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Affiliation(s)
- Md Saddam Hossain
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, South Dakota, USA
- BioSNTR, South Dakota State University, Brookings, South Dakota, USA
| | - Jason G Kerkvliet
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, South Dakota, USA
- BioSNTR, South Dakota State University, Brookings, South Dakota, USA
| | - Adam D Hoppe
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, South Dakota, USA
- BioSNTR, South Dakota State University, Brookings, South Dakota, USA
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4
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Gao R, Wang Z, Uprety T, Sreenivasan CC, Sheng Z, Hause BM, Brunick C, Wu H, Luke T, Bausch CL, Sullivan EJ, Hoppe AD, Huber VC, Wang D, Li F. A fully human monoclonal antibody possesses antibody-dependent cellular cytotoxicity (ADCC) activity against the H1 subtype of influenza A virus by targeting a conserved epitope at the HA1 protomer interface. J Med Virol 2023; 95:e28901. [PMID: 37394780 DOI: 10.1002/jmv.28901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 04/28/2023] [Accepted: 06/11/2023] [Indexed: 07/04/2023]
Abstract
The DiversitabTM system produces target specific high titer fully human polyclonal IgG immunoglobulins from transchromosomic (Tc) bovines shown to be safe and effective against multiple virulent pathogens in animal studies and Phase 1, 2 and 3 human clinical trials. We describe the functional properties of a human monoclonal antibody (mAb), 38C2, identified from this platform, which recognizes recombinant H1 hemagglutinins (HAs) and induces appreciable antibody-dependent cellular cytotoxicity (ADCC) activity in vitro. Interestingly, 38C2 monoclonal antibody demonstrated no detectable neutralizing activity against H1N1 virus in both hemagglutination inhibition and virus neutralization assays. Nevertheless, this human monoclonal antibody induced appreciable ADCC against cells infected with multiple H1N1 strains. The HA-binding activity of 38C2 was also demonstrated in flow cytometry using Madin-Darby canine kidney cells infected with multiple influenza A H1N1 viruses. Through further investigation with the enzyme-linked immunosorbent assay involving the HA peptide array and 3-dimensional structural modeling, we demonstrated that 38C2 appears to target a conserved epitope located at the HA1 protomer interface of H1N1 influenza viruses. A novel mode of HA-binding and in vitro ADCC activity pave the way for further evaluation of 38C2 as a potential therapeutic agent to treat influenza virus infections in humans.
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Affiliation(s)
- Rongyuan Gao
- Department of Biology and Microbiology, South Dakota State University, Brookings, South Dakota, USA
| | - Zhao Wang
- Department of Biology and Microbiology, South Dakota State University, Brookings, South Dakota, USA
| | - Tirth Uprety
- Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, Kentucky, USA
| | - Chithra C Sreenivasan
- Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, Kentucky, USA
| | - Zizhang Sheng
- Zuckerman Mind Brian Behavior Institute, Columbia University, New York, New York, USA
| | - Ben M Hause
- Research and Development Division, Cambridge Technologies Inc, Worthington, Minnesota, USA
| | - Colin Brunick
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, South Dakota, USA
| | - Hua Wu
- SAB Biotherapeutics, Sioux Falls, South Dakota, USA
| | - Thomas Luke
- SAB Biotherapeutics, Sioux Falls, South Dakota, USA
| | | | | | - Adam D Hoppe
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, South Dakota, USA
| | - Victor C Huber
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, South Dakota, USA
| | - Dan Wang
- Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, Kentucky, USA
| | - Feng Li
- Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, Kentucky, USA
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5
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Anderson RH, Sochacki KA, Vuppula H, Scott BL, Bailey EM, Schultz MM, Kerkvliet JG, Taraska JW, Hoppe AD, Francis KR. Sterols lower energetic barriers of membrane bending and fission necessary for efficient clathrin-mediated endocytosis. Cell Rep 2022; 38:110371. [PMID: 35139372 DOI: 10.1016/j.celrep.2022.110371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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6
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Quinn SE, Huang L, Kerkvliet JG, Swanson JA, Smith S, Hoppe AD, Anderson RB, Thiex NW, Scott BL. Author Correction: The structural dynamics of macropinosome formation and PI3-kinase-mediated sealing revealed by lattice light sheet microscopy. Nat Commun 2021; 12:7266. [PMID: 34880216 PMCID: PMC8655030 DOI: 10.1038/s41467-021-27411-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Shayne E Quinn
- Nanoscience and Nanoengineering, South Dakota School of Mines and Technology (South Dakota Mines), Rapid City, SD, USA
- BioSNTR, South Dakota Mines, Rapid City, SD, USA
| | - Lu Huang
- Department of Biology and Microbiology, South Dakota State University (SDSU), Brookings, SD, USA
- BioSNTR, SDSU, Brookings, SD, USA
| | - Jason G Kerkvliet
- BioSNTR, SDSU, Brookings, SD, USA
- Department of Chemistry and Biochemistry, SDSU, Brookings, SD, USA
| | - Joel A Swanson
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Steve Smith
- Nanoscience and Nanoengineering, South Dakota School of Mines and Technology (South Dakota Mines), Rapid City, SD, USA
- BioSNTR, South Dakota Mines, Rapid City, SD, USA
| | - Adam D Hoppe
- BioSNTR, SDSU, Brookings, SD, USA
- Department of Chemistry and Biochemistry, SDSU, Brookings, SD, USA
| | - Robert B Anderson
- Nanoscience and Nanoengineering, South Dakota School of Mines and Technology (South Dakota Mines), Rapid City, SD, USA.
- BioSNTR, South Dakota Mines, Rapid City, SD, USA.
| | - Natalie W Thiex
- Department of Biology and Microbiology, South Dakota State University (SDSU), Brookings, SD, USA.
- BioSNTR, SDSU, Brookings, SD, USA.
| | - Brandon L Scott
- Nanoscience and Nanoengineering, South Dakota School of Mines and Technology (South Dakota Mines), Rapid City, SD, USA.
- BioSNTR, South Dakota Mines, Rapid City, SD, USA.
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7
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Anderson RH, Sochacki KA, Vuppula H, Scott BL, Bailey EM, Schultz MM, Kerkvliet JG, Taraska JW, Hoppe AD, Francis KR. Sterols lower energetic barriers of membrane bending and fission necessary for efficient clathrin-mediated endocytosis. Cell Rep 2021; 37:110008. [PMID: 34788623 PMCID: PMC8620193 DOI: 10.1016/j.celrep.2021.110008] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 08/03/2021] [Accepted: 10/26/2021] [Indexed: 01/16/2023] Open
Abstract
Clathrin-mediated endocytosis (CME) is critical for cellular signal transduction, receptor recycling, and membrane homeostasis in mammalian cells. Acute depletion of cholesterol disrupts CME, motivating analysis of CME dynamics in the context of human disorders of cholesterol metabolism. We report that inhibition of post-squalene cholesterol biosynthesis impairs CME. Imaging of membrane bending dynamics and the CME pit ultrastructure reveals prolonged clathrin pit lifetimes and shallow clathrin-coated structures, suggesting progressive impairment of curvature generation correlates with diminishing sterol abundance. Sterol structural requirements for efficient CME include 3′ polar head group and B-ring conformation, resembling the sterol structural prerequisites for tight lipid packing and polarity. Furthermore, Smith-Lemli-Opitz fibroblasts with low cholesterol abundance exhibit deficits in CME-mediated transferrin internalization. We conclude that sterols lower the energetic costs of membrane bending during pit formation and vesicular scission during CME and suggest that reduced CME activity may contribute to cellular phenotypes observed within disorders of cholesterol metabolism. Anderson et al. demonstrate that sterol abundance and identity play a dominant role in facilitating clathrin-mediated endocytosis. Detailed analyses of clathrin-coated pits under sterol depletion support a requirement for sterol-mediated membrane bending during multiple stages of endocytosis, implicating endocytic dysfunction within the pathogenesis of disorders of cholesterol metabolism.
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Affiliation(s)
- Ruthellen H Anderson
- Sanford School of Medicine, University of South Dakota, Sioux Falls, SD 57105, USA; Cellular Therapies and Stem Cell Biology Group, Sanford Research, Sioux Falls, SD 57104, USA
| | - Kem A Sochacki
- Laboratory of Molecular Biophysics, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20814, USA
| | - Harika Vuppula
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD 57007, USA; BioSystems Networks and Translational Research Center, Brookings, SD 57007, USA
| | - Brandon L Scott
- Nanoscience and Nanoengineering, South Dakota School of Mines & Technology, Rapid City, SD 57701, USA
| | - Elizabeth M Bailey
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD 57007, USA; BioSystems Networks and Translational Research Center, Brookings, SD 57007, USA
| | - Maycie M Schultz
- Cellular Therapies and Stem Cell Biology Group, Sanford Research, Sioux Falls, SD 57104, USA
| | - Jason G Kerkvliet
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD 57007, USA; BioSystems Networks and Translational Research Center, Brookings, SD 57007, USA
| | - Justin W Taraska
- Laboratory of Molecular Biophysics, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20814, USA
| | - Adam D Hoppe
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD 57007, USA; BioSystems Networks and Translational Research Center, Brookings, SD 57007, USA.
| | - Kevin R Francis
- Cellular Therapies and Stem Cell Biology Group, Sanford Research, Sioux Falls, SD 57104, USA; Department of Pediatrics, Sanford School of Medicine, University of South Dakota, Sioux Falls, SD 57105, USA.
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8
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Quinn SE, Huang L, Kerkvliet JG, Swanson JA, Smith S, Hoppe AD, Anderson RB, Thiex NW, Scott BL. The structural dynamics of macropinosome formation and PI3-kinase-mediated sealing revealed by lattice light sheet microscopy. Nat Commun 2021. [PMID: 34376698 DOI: 10.1101/2020.12.01.390195] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2023] Open
Abstract
Macropinosomes are formed by shaping actin-rich plasma membrane ruffles into large intracellular organelles in a phosphatidylinositol 3-kinase (PI3K)-coordinated manner. Here, we utilize lattice lightsheet microscopy and image visualization methods to map the three-dimensional structure and dynamics of macropinosome formation relative to PI3K activity. We show that multiple ruffling morphologies produce macropinosomes and that the majority form through collisions of adjacent PI3K-rich ruffles. By combining multiple volumetric representations of the plasma membrane structure and PI3K products, we show that PI3K activity begins early throughout the entire ruffle volume and continues to increase until peak activity concentrates at the base of the ruffle after the macropinosome closes. Additionally, areas of the plasma membrane rich in ruffling had increased PI3K activity and produced many macropinosomes of various sizes. Pharmacologic inhibition of PI3K activity had little effect on the rate and morphology of membrane ruffling, demonstrating that early production of 3'-phosphoinositides within ruffles plays a minor role in regulating their morphology. However, 3'-phosphoinositides are critical for the fusogenic activity that seals ruffles into macropinosomes. Taken together, these data indicate that local PI3K activity is amplified in ruffles and serves as a priming mechanism for closure and sealing of ruffles into macropinosomes.
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Affiliation(s)
- Shayne E Quinn
- Nanoscience and Nanoengineering, South Dakota School of Mines and Technology (South Dakota Mines), Rapid City, SD, USA
- BioSNTR, South Dakota Mines, Rapid City, SD, USA
| | - Lu Huang
- Department of Biology and Microbiology, South Dakota State University (SDSU), Brookings, SD, USA
- BioSNTR, SDSU, Brookings, SD, USA
| | - Jason G Kerkvliet
- BioSNTR, SDSU, Brookings, SD, USA
- Department of Chemistry and Biochemistry, SDSU, Brookings, SD, USA
| | - Joel A Swanson
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Steve Smith
- Nanoscience and Nanoengineering, South Dakota School of Mines and Technology (South Dakota Mines), Rapid City, SD, USA
- BioSNTR, South Dakota Mines, Rapid City, SD, USA
| | - Adam D Hoppe
- BioSNTR, SDSU, Brookings, SD, USA
- Department of Chemistry and Biochemistry, SDSU, Brookings, SD, USA
| | - Robert B Anderson
- Nanoscience and Nanoengineering, South Dakota School of Mines and Technology (South Dakota Mines), Rapid City, SD, USA.
- BioSNTR, South Dakota Mines, Rapid City, SD, USA.
| | - Natalie W Thiex
- Department of Biology and Microbiology, South Dakota State University (SDSU), Brookings, SD, USA.
- BioSNTR, SDSU, Brookings, SD, USA.
| | - Brandon L Scott
- Nanoscience and Nanoengineering, South Dakota School of Mines and Technology (South Dakota Mines), Rapid City, SD, USA.
- BioSNTR, South Dakota Mines, Rapid City, SD, USA.
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9
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Quinn SE, Huang L, Kerkvliet JG, Swanson JA, Smith S, Hoppe AD, Anderson RB, Thiex NW, Scott BL. The structural dynamics of macropinosome formation and PI3-kinase-mediated sealing revealed by lattice light sheet microscopy. Nat Commun 2021; 12:4838. [PMID: 34376698 PMCID: PMC8355319 DOI: 10.1038/s41467-021-25187-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 07/22/2021] [Indexed: 12/11/2022] Open
Abstract
Macropinosomes are formed by shaping actin-rich plasma membrane ruffles into large intracellular organelles in a phosphatidylinositol 3-kinase (PI3K)-coordinated manner. Here, we utilize lattice lightsheet microscopy and image visualization methods to map the three-dimensional structure and dynamics of macropinosome formation relative to PI3K activity. We show that multiple ruffling morphologies produce macropinosomes and that the majority form through collisions of adjacent PI3K-rich ruffles. By combining multiple volumetric representations of the plasma membrane structure and PI3K products, we show that PI3K activity begins early throughout the entire ruffle volume and continues to increase until peak activity concentrates at the base of the ruffle after the macropinosome closes. Additionally, areas of the plasma membrane rich in ruffling had increased PI3K activity and produced many macropinosomes of various sizes. Pharmacologic inhibition of PI3K activity had little effect on the rate and morphology of membrane ruffling, demonstrating that early production of 3'-phosphoinositides within ruffles plays a minor role in regulating their morphology. However, 3'-phosphoinositides are critical for the fusogenic activity that seals ruffles into macropinosomes. Taken together, these data indicate that local PI3K activity is amplified in ruffles and serves as a priming mechanism for closure and sealing of ruffles into macropinosomes.
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Affiliation(s)
- Shayne E Quinn
- Nanoscience and Nanoengineering, South Dakota School of Mines and Technology (South Dakota Mines), Rapid City, SD, USA
- BioSNTR, South Dakota Mines, Rapid City, SD, USA
| | - Lu Huang
- Department of Biology and Microbiology, South Dakota State University (SDSU), Brookings, SD, USA
- BioSNTR, SDSU, Brookings, SD, USA
| | - Jason G Kerkvliet
- BioSNTR, SDSU, Brookings, SD, USA
- Department of Chemistry and Biochemistry, SDSU, Brookings, SD, USA
| | - Joel A Swanson
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Steve Smith
- Nanoscience and Nanoengineering, South Dakota School of Mines and Technology (South Dakota Mines), Rapid City, SD, USA
- BioSNTR, South Dakota Mines, Rapid City, SD, USA
| | - Adam D Hoppe
- BioSNTR, SDSU, Brookings, SD, USA
- Department of Chemistry and Biochemistry, SDSU, Brookings, SD, USA
| | - Robert B Anderson
- Nanoscience and Nanoengineering, South Dakota School of Mines and Technology (South Dakota Mines), Rapid City, SD, USA.
- BioSNTR, South Dakota Mines, Rapid City, SD, USA.
| | - Natalie W Thiex
- Department of Biology and Microbiology, South Dakota State University (SDSU), Brookings, SD, USA.
- BioSNTR, SDSU, Brookings, SD, USA.
| | - Brandon L Scott
- Nanoscience and Nanoengineering, South Dakota School of Mines and Technology (South Dakota Mines), Rapid City, SD, USA.
- BioSNTR, South Dakota Mines, Rapid City, SD, USA.
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10
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Neises JZ, Hossain MS, Sultana R, Wanniarachchi KN, Wollman JW, Nelson E, Specker BL, Hoppe AD, Lawson SR, Thiex NW. Seroprevalence of SARS-CoV-2 antibodies among rural healthcare workers. J Med Virol 2021; 93:6611-6618. [PMID: 34289148 PMCID: PMC8426917 DOI: 10.1002/jmv.27224] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 07/17/2021] [Indexed: 11/19/2022]
Abstract
The objective of this longitudinal cohort study was to determine the seroprevalence of antibodies to severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2) in healthcare workers employed at healthcare settings in three rural counties in eastern South Dakota and western Minnesota from May 13, 2020, through December 22, 2020. Three blood draws were performed at five clinical sites and tested for the presence of antibodies against the SARS‐CoV‐2. Serum samples were tested for the presence of antibodies using a fluorescent microsphere immunoassay (FMIA), neutralization of SARS‐CoV‐2 spike‐pseudotyped particles (SARS‐CoV‐2pp) assay, and serum virus neutralization (SVN) assay. The seroprevalence was determined to be 1/336 (0.29%) for samples collected from 5/13/20 to 7/13/20, 5/260 (1.92%) for samples collected from 8/13/20 to 9/25/20, and 35/235 (14.89%) for samples collected from 10/16/20 to 12/22/20. Eight of the 35 (22.8%) seropositive individuals identified in the final draw did not report a previous diagnosis with COVID‐19. There was a high correlation (>90%) between the FMIA and virus neutralization assays. Each clinical site's seroprevalence was higher than the cumulative incidence for the general public in the respective county as reported by state public health agencies. As of December 2020, there was a high percentage (85%) of seronegative individuals in the study population.
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Affiliation(s)
- Jordan Z Neises
- Department of Biology and Microbiology, South Dakota State University, Brookings, South Dakota, USA
| | - Md Saddam Hossain
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, South Dakota, USA
| | - Rifat Sultana
- Department of Biology and Microbiology, South Dakota State University, Brookings, South Dakota, USA
| | - Kevin N Wanniarachchi
- Department of Biology and Microbiology, South Dakota State University, Brookings, South Dakota, USA
| | - Jared W Wollman
- Department of Biology and Microbiology, South Dakota State University, Brookings, South Dakota, USA
| | - Eric Nelson
- Department of Veterinary and Biomedical Sciences, South Dakota State University, Brookings, South Dakota, USA
| | - Bonny L Specker
- EA Martin Program in Human Nutrition, South Dakota State University, Brookings, South Dakota, USA
| | - Adam D Hoppe
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, South Dakota, USA
| | - Steven R Lawson
- Department of Veterinary and Biomedical Sciences, South Dakota State University, Brookings, South Dakota, USA
| | - Natalie W Thiex
- Department of Biology and Microbiology, South Dakota State University, Brookings, South Dakota, USA
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11
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Bailey EM, Choudhury A, Vuppula H, Ortiz DF, Schaeck J, Manning AM, Bosques CJ, Hoppe AD. Engineered IgG1-Fc Molecules Define Valency Control of Cell Surface Fcγ Receptor Inhibition and Activation in Endosomes. Front Immunol 2021; 11:617767. [PMID: 33679705 PMCID: PMC7928370 DOI: 10.3389/fimmu.2020.617767] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 12/24/2020] [Indexed: 12/27/2022] Open
Abstract
The inhibition of Fcγ receptors (FcγR) is an attractive strategy for treating diseases driven by IgG immune complexes (IC). Previously, we demonstrated that an engineered tri-valent arrangement of IgG1 Fc domains (SIF1) potently inhibited FcγR activation by IC, whereas a penta-valent Fc molecule (PentX) activated FcγR, potentially mimicking ICs and leading to Syk phosphorylation. Thus, a precise balance exists between the number of engaged FcγRs for inhibition versus activation. Here, we demonstrate that Fc valency differentially controls FcγR activation and inhibition within distinct subcellular compartments. Large Fc multimer clusters consisting of 5-50 Fc domains predominately recruited Syk-mScarlet to patches on the plasma membrane, whereas PentX exclusively recruited Syk-mScarlet to endosomes in human monocytic cell line (THP-1 cells). In contrast, SIF1, similar to monomeric Fc, spent longer periods docked to FcγRs on the plasma membrane and did not accumulate and recruit Syk-mScarlet within large endosomes. Single particle tracking (SPT) of fluorescent engineered Fc molecules and Syk-mScarlet at the plasma membrane imaged by total internal reflection fluorescence microscopy (SPT-TIRF), revealed that Syk-mScarlet sampled the plasma membrane was not recruited to FcγR docked with any of the engineered Fc molecules at the plasma membrane. Furthermore, the motions of FcγRs docked with recombinant Fc (rFc), SIF1 or PentX, displayed similar motions with D ~ 0.15 μm2/s, indicating that SIF1 and PentX did not induce reorganization or microclustering of FcγRs beyond the ligating valency. Multicolor SPT-TIRF and brightness analysis of docked rFc, SIF1 and PentX also indicated that FcγRs were not pre-assembled into clusters. Taken together, activation on the plasma membrane requires assembly of more than 5 FcγRs. Unlike rFc or SIF1, PentX accumulated Syk-mScarlet on endosomes indicating that the threshold for FcγR activation on endosomes is lower than on the plasma membrane. We conclude that the inhibitory effects of SIF1 are mediated by stabilizing a ligated and inactive FcγR on the plasma membrane. Thus, FcγR inhibition can be achieved by low valency ligation with SIF1 that behaves similarly to FcγR docked with monomeric IgG.
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Affiliation(s)
- Elizabeth M Bailey
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD, United States.,BioSystems Networks and Translational Research, South Dakota State University, Brookings, SD, United States
| | | | - Harika Vuppula
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD, United States.,BioSystems Networks and Translational Research, South Dakota State University, Brookings, SD, United States
| | | | - John Schaeck
- Momenta Pharmaceuticals, Cambridge, MA, United States
| | | | | | - Adam D Hoppe
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD, United States.,BioSystems Networks and Translational Research, South Dakota State University, Brookings, SD, United States
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12
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Yang J, Ma A, Hoppe AD, Wang C, Li Y, Zhang C, Wang Y, Liu B, Ma Q. Prediction of regulatory motifs from human Chip-sequencing data using a deep learning framework. Nucleic Acids Res 2019; 47:7809-7824. [PMID: 31372637 PMCID: PMC6735894 DOI: 10.1093/nar/gkz672] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 07/23/2019] [Indexed: 11/24/2022] Open
Abstract
The identification of transcription factor binding sites and cis-regulatory motifs is a frontier whereupon the rules governing protein–DNA binding are being revealed. Here, we developed a new method (DEep Sequence and Shape mOtif or DESSO) for cis-regulatory motif prediction using deep neural networks and the binomial distribution model. DESSO outperformed existing tools, including DeepBind, in predicting motifs in 690 human ENCODE ChIP-sequencing datasets. Furthermore, the deep-learning framework of DESSO expanded motif discovery beyond the state-of-the-art by allowing the identification of known and new protein–protein–DNA tethering interactions in human transcription factors (TFs). Specifically, 61 putative tethering interactions were identified among the 100 TFs expressed in the K562 cell line. In this work, the power of DESSO was further expanded by integrating the detection of DNA shape features. We found that shape information has strong predictive power for TF–DNA binding and provides new putative shape motif information for human TFs. Thus, DESSO improves in the identification and structural analysis of TF binding sites, by integrating the complexities of DNA binding into a deep-learning framework.
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Affiliation(s)
- Jinyu Yang
- Department of Biomedical Informatics, College of Medicine, The Ohio State University, Columbus, OH 43210, USA.,Department of Computer Science and Engineering, The University of Texas at Arlington, Arlington, TX 76010, USA
| | - Anjun Ma
- Department of Biomedical Informatics, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Adam D Hoppe
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD 57007, USA.,BioSNTR, Brookings, SD 57007, USA
| | - Cankun Wang
- Department of Biomedical Informatics, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Yang Li
- School of Mathematics, Shandong University, Jinan 250100, China
| | - Chi Zhang
- Department of Medical and Molecular Genetics, School of Medicine, Indiana University, Indianapolis, IN 46202, USA
| | - Yan Wang
- School of Artificial Intelligence, Jilin University, Changchun 130012, China
| | - Bingqiang Liu
- School of Mathematics, Shandong University, Jinan 250100, China
| | - Qin Ma
- Department of Biomedical Informatics, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
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13
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Lin T, Scott BL, Hoppe AD, Chakravarty S. FRETting about the affinity of bimolecular protein-protein interactions. Protein Sci 2019; 27:1850-1856. [PMID: 30052312 DOI: 10.1002/pro.3482] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 07/05/2018] [Accepted: 07/12/2018] [Indexed: 01/19/2023]
Abstract
Fluorescence resonance energy transfer (FRET) is a powerful tool to study macromolecular interactions such as protein-protein interactions (PPIs). Fluorescent protein (FP) fusions enable FRET-based PPI analysis of signaling pathways and molecular structure in living cells. Despite FRET's importance in PPI studies, FRET has seen limited use in quantifying the affinities of PPIs in living cells. Here, we have explored the relationship between FRET efficiency and PPI affinity over a wide range when expressed from a single plasmid system in Escherichia coli. Using live-cell microscopy and a set of 20 pairs of small interacting proteins, belonging to different structural folds and interaction affinities, we demonstrate that FRET efficiency can reliably measure the dissociation constant (KD ) over a range of mM to nM. A 10-fold increase in the interaction affinity results in 0.05 unit increase in FRET efficiency, providing sufficient resolution to quantify large affinity differences (> 10-fold) using live-cell FRET. This approach provides a rapid and simple strategy for assessment of PPI affinities over a wide range and will have utility for high-throughput analysis of protein interactions.
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Affiliation(s)
- Tao Lin
- Chemistry and Biochemistry, South Dakota State University, Brookings, South Dakota, 57007
| | - Brandon L Scott
- Chemistry and Biochemistry, South Dakota State University, Brookings, South Dakota, 57007
| | - Adam D Hoppe
- Chemistry and Biochemistry, South Dakota State University, Brookings, South Dakota, 57007.,BioSNTR, Brookings, South Dakota, 57007
| | - Suvobrata Chakravarty
- Chemistry and Biochemistry, South Dakota State University, Brookings, South Dakota, 57007.,BioSNTR, Brookings, South Dakota, 57007
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14
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Anderson RH, Kerkvliet JG, Otta JJ, Ross AD, Leiferman PC, Hoppe AD, Francis KR. Generation of a CLTA reporter human induced pluripotent stem cell line, CRMi001-A-1, using the CRISPR/Cas9 system to monitor endogenous clathrin trafficking. Stem Cell Res 2018; 33:95-99. [PMID: 30340091 PMCID: PMC6383648 DOI: 10.1016/j.scr.2018.10.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 09/18/2018] [Accepted: 10/01/2018] [Indexed: 11/29/2022] Open
Abstract
The most highly studied endocytic pathway, clathrin-dependent endocytosis, mediates a wide range of fundamental processes including nutrient internalization, receptor recycling, and signal transduction. In order to model tissue specific and developmental aspects of this process, CRISPR/Cas9 genomic editing was utilized to fluorescently label the C-terminus of clathrin light chain A (CLTA) within the phenotypically normal, parental CRMi001-A human induced pluripotent stem cell line. Successfully edited cells were isolated by fluorescently activated cell sorting, remained karyotypically normal, and maintained their differentiation potential. This cell line facilitates imaging of endogenous clathrin trafficking within varied cell types.
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Affiliation(s)
- Ruthellen H Anderson
- Sanford School of Medicine, University of South Dakota, Sioux Falls, SD, USA; Cellular Therapies and Stem Cell Biology Group, Sanford Research, Sioux Falls, SD, USA
| | - Jason G Kerkvliet
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD, USA; BioSystems Networks and Translational Research Center, Brookings, SD, USA
| | - Jaelin J Otta
- Sanford School of Medicine, University of South Dakota, Sioux Falls, SD, USA
| | - Alan D Ross
- Sanford Medical Genetics Laboratory, Cytogenetics Division, Sanford Hospital, Sioux Falls, SD, USA
| | - Patricia C Leiferman
- Sanford School of Medicine, University of South Dakota, Sioux Falls, SD, USA; Sanford Medical Genetics Laboratory, Cytogenetics Division, Sanford Hospital, Sioux Falls, SD, USA
| | - Adam D Hoppe
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD, USA; BioSystems Networks and Translational Research Center, Brookings, SD, USA
| | - Kevin R Francis
- Sanford School of Medicine, University of South Dakota, Sioux Falls, SD, USA; Cellular Therapies and Stem Cell Biology Group, Sanford Research, Sioux Falls, SD, USA.
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15
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Cypher LR, Bielecki TA, Adepegba O, Huang L, An W, Iseka F, Luan H, Tom E, Storck MD, Hoppe AD, Band V, Band H. CSF-1 receptor signalling is governed by pre-requisite EHD1 mediated receptor display on the macrophage cell surface. Cell Signal 2016; 28:1325-1335. [PMID: 27224507 DOI: 10.1016/j.cellsig.2016.05.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 05/13/2016] [Accepted: 05/16/2016] [Indexed: 12/23/2022]
Abstract
Colony stimulating factor-1 receptor (CSF-1R), a receptor tyrosine kinase (RTK), is the master regulator of macrophage biology. CSF-1 can bind CSF-1R resulting in receptor activation and signalling essential for macrophage functions such as proliferation, differentiation, survival, polarization, phagocytosis, cytokine secretion, and motility. CSF-1R activation can only occur after the receptor is presented on the macrophage cell surface. This process is reliant upon the underlying macrophage receptor trafficking machinery. However, the mechanistic details governing this process are incompletely understood. C-terminal Eps15 Homology Domain-containing (EHD) proteins have recently emerged as key regulators of receptor trafficking but have not yet been studied in the context of macrophage CSF-1R signalling. In this manuscript, we utilize primary bone-marrow derived macrophages (BMDMs) to reveal a novel function of EHD1 as a regulator of CSF-1R abundance on the cell surface. We report that EHD1-knockout (EHD1-KO) macrophages cell surface and total CSF-1R levels are significantly decreased. The decline in CSF-1R levels corresponds with reduced downstream macrophage functions such as cell proliferation, migration, and spreading. In EHD1-KO macrophages, transport of newly synthesized CSF-1R to the macrophage cell surface was reduced and was associated with the shunting of the receptor to the lysosome, which resulted in receptor degradation. These findings reveal a novel and functionally important role for EHD1 in governing CSF-1R signalling via regulation of anterograde transport of CSF-1R to the macrophage cell surface.
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Affiliation(s)
- Luke R Cypher
- Eppley Cancer Institute for Research in Cancer & Allied Diseases, University of Nebraska Medical Center, Omaha, NE, United States
| | - Timothy Alan Bielecki
- Eppley Cancer Institute for Research in Cancer & Allied Diseases, University of Nebraska Medical Center, Omaha, NE, United States
| | | | - Lu Huang
- Department of Chemistry and Biochemistry, BioSNTR, South Dakota State University, Brookings, SD, United States
| | - Wei An
- Department of Genetics, Cell Biology, & Anatomy, University of Nebraska Medical Center, Omaha, NE, United States
| | - Fany Iseka
- Department of Genetics, Cell Biology, & Anatomy, University of Nebraska Medical Center, Omaha, NE, United States
| | | | - Eric Tom
- Department of Biochemistry & Molecular Biology, University of Nebraska Medical Center, Omaha, NE, United States
| | - Matthew D Storck
- Eppley Cancer Institute for Research in Cancer & Allied Diseases, University of Nebraska Medical Center, Omaha, NE, United States
| | - Adam D Hoppe
- Department of Chemistry and Biochemistry, BioSNTR, South Dakota State University, Brookings, SD, United States
| | - Vimla Band
- Eppley Cancer Institute for Research in Cancer & Allied Diseases, University of Nebraska Medical Center, Omaha, NE, United States; Department of Genetics, Cell Biology, & Anatomy, University of Nebraska Medical Center, Omaha, NE, United States
| | - Hamid Band
- Eppley Cancer Institute for Research in Cancer & Allied Diseases, University of Nebraska Medical Center, Omaha, NE, United States; Department of Genetics, Cell Biology, & Anatomy, University of Nebraska Medical Center, Omaha, NE, United States.
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16
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Scott BL, Hoppe AD. Three-Dimensional Reconstruction of Three-Way FRET Microscopy Improves Imaging of Multiple Protein-Protein Interactions. PLoS One 2016; 11:e0152401. [PMID: 27023704 PMCID: PMC4811573 DOI: 10.1371/journal.pone.0152401] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 03/14/2016] [Indexed: 11/19/2022] Open
Abstract
Fluorescence resonance energy transfer (FRET) microscopy is a powerful tool for imaging the interactions between fluorescently tagged proteins in two-dimensions. For FRET microscopy to reach its full potential, it must be able to image more than one pair of interacting molecules and image degradation from out-of-focus light must be reduced. Here we extend our previous work on the application of maximum likelihood methods to the 3-dimensional reconstruction of 3-way FRET interactions within cells. We validated the new method (3D-3Way FRET) by simulation and fluorescent protein test constructs expressed in cells. In addition, we improved the computational methods to create a 2-log reduction in computation time over our previous method (3DFSR). We applied 3D-3Way FRET to image the 3D subcellular distributions of HIV Gag assembly. Gag fused to three different FPs (CFP, YFP, and RFP), assembled into viral-like particles and created punctate FRET signals that become visible on the cell surface when 3D-3Way FRET was applied to the data. Control experiments in which YFP-Gag, RFP-Gag and free CFP were expressed, demonstrated localized FRET between YFP and RFP at sites of viral assembly that were not associated with CFP. 3D-3Way FRET provides the first approach for quantifying multiple FRET interactions while improving the 3D resolution of FRET microscopy data without introducing bias into the reconstructed estimates. This method should allow improvement of widefield, confocal and superresolution FRET microscopy data.
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Affiliation(s)
- Brandon L. Scott
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, South Dakota, United States of America
- BioSNTR, South Dakota State University, Brookings, South Dakota, United States of America
| | - Adam D. Hoppe
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, South Dakota, United States of America
- BioSNTR, South Dakota State University, Brookings, South Dakota, United States of America
- * E-mail:
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17
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Lin J, Kurilova S, Scott BL, Bosworth E, Iverson BE, Bailey EM, Hoppe AD. TIRF imaging of Fc gamma receptor microclusters dynamics and signaling on macrophages during frustrated phagocytosis. BMC Immunol 2016; 17:5. [PMID: 26970734 PMCID: PMC4789268 DOI: 10.1186/s12865-016-0143-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 03/03/2016] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Recent evidence indicates that in addition to the T-cell receptor, microclustering is an important mechanism for the activation of the B-cell receptor and the mast cell Fcε-receptor. In macrophages and neutrophils, particles opsonized with immunoglobulin G (IgG) antibodies activate the phagocytic Fcγ-receptor (FcγR) leading to rearrangements of the actin cytoskeleton. The purpose of this study was to establish a system for high-resolution imaging of FcγR microclustering dynamics and the recruitment of the downstream signaling machinery to these microclusters. METHODS We developed a supported lipid bilayer platform with incorporated antibodies on its surface to study the formation and maturation of FcγR signaling complexes in macrophages. Time-lapse multicolor total internal reflection microscopy was used to capture the formation of FcγR-IgG microclusters and their assembly into signaling complexes on the plasma membrane of murine bone marrow derived macrophages. RESULTS Upon antibody binding, macrophages formed FcγR-IgG complexes at the leading edge of advancing pseudopods. These complexes then moved toward the center of the cell to form a structure reminiscent of the supramolecular complex observed in the T-cell/antigen presenting cell immune synapse. Colocalization of signaling protein Syk with nascent clusters of antibodies indicated that phosphorylated receptor complexes underwent maturation as they trafficked toward the center of the cell. Additionally, imaging of fluorescent BtkPH domains indicated that 3'-phosphoinositides propagated laterally away from the FcγR microclusters. CONCLUSION We demonstrate that surface-associated but mobile IgG induces the formation of FcγR microclusters at the pseudopod leading edge. These clusters recruit Syk and drive the production of diffusing PI(3,4,5)P3 that is coordinated with lamellar actin polymerization. Upon reaching maximal extension, FcγR microclusters depart from the leading edge and are transported to the center of the cellular contact region to form a synapse-like structure, analogous to the process observed for T-cell receptors.
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Affiliation(s)
- Jia Lin
- Department of Chemistry and Biochemistry, Avera Health and Science Center 131, South Dakota State University, Brookings, SD, 57007, USA.,Department of Pathology, University of New Mexico Health Sciences Center, University of New Mexico, MSC 08-4640, Albuquerque, New Mexico, 87131, USA
| | - Svetlana Kurilova
- Department of Chemistry and Biochemistry, Avera Health and Science Center 131, South Dakota State University, Brookings, SD, 57007, USA.,BioSNTR, South Dakota State University, Brookings, SD, 57007, USA
| | - Brandon L Scott
- Department of Chemistry and Biochemistry, Avera Health and Science Center 131, South Dakota State University, Brookings, SD, 57007, USA.,BioSNTR, South Dakota State University, Brookings, SD, 57007, USA
| | - Elizabeth Bosworth
- Department of Chemistry and Biochemistry, Avera Health and Science Center 131, South Dakota State University, Brookings, SD, 57007, USA
| | - Bradley E Iverson
- Department of Chemistry and Biochemistry, Avera Health and Science Center 131, South Dakota State University, Brookings, SD, 57007, USA
| | - Elizabeth M Bailey
- Department of Chemistry and Biochemistry, Avera Health and Science Center 131, South Dakota State University, Brookings, SD, 57007, USA.,BioSNTR, South Dakota State University, Brookings, SD, 57007, USA
| | - Adam D Hoppe
- Department of Chemistry and Biochemistry, Avera Health and Science Center 131, South Dakota State University, Brookings, SD, 57007, USA. .,BioSNTR, South Dakota State University, Brookings, SD, 57007, USA.
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18
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Hoppe AD, Low-Nam S, Scott BL, Kerkvliet JG. Imaging Sub-Diffraction Membrane Curvature Dynamics during Clathrin Mediated Endocytosis. Biophys J 2015. [DOI: 10.1016/j.bpj.2014.11.199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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19
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Lou J, Low-Nam ST, Kerkvliet JG, Hoppe AD. Delivery of CSF-1R to the lumen of macropinosomes promotes its destruction in macrophages. J Cell Sci 2014; 127:5228-39. [PMID: 25335894 DOI: 10.1242/jcs.154393] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Activation of the macrophage colony stimulating factor-1 receptor (CSF-1R) by CSF-1 stimulates pronounced macropinocytosis and drives proliferation of macrophages. Although the role of macropinocytosis in CSF-1R signaling remains unknown, we show here that, despite internalizing large quantities of plasma membrane, macropinosomes contribute little to the internalization of the CSF-1-CSF-1R complex. Rather, internalization of the CSF-1R in small endocytic vesicles that are sensitive to clathrin disruption, outcompetes macropinosomes for CSF-1R endocytosis. Following internalization, small vesicles carrying the CSF-1R underwent homotypic fusion and then trafficked to newly formed macropinosomes bearing Rab5. As these macropinosomes matured, acquiring Rab7, the CSF-1R was transported into their lumen and degraded. Inhibition of macropinocytosis delayed receptor degradation despite no disruption to CSF-1R endocytosis. These data indicate that CSF-1-stimulated macropinosomes are sites of multivesicular body formation and accelerate CSF-1R degradation. Furthermore, we demonstrate that macropinocytosis and cell growth have a matching dose dependence on CSF-1, suggesting that macropinosomes might be a central mechanism coupling CSF-1R signaling and macrophage growth.
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Affiliation(s)
- Jieqiong Lou
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, 57007 SD, USA
| | - Shalini T Low-Nam
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, 57007 SD, USA
| | - Jason G Kerkvliet
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, 57007 SD, USA
| | - Adam D Hoppe
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, 57007 SD, USA
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20
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Sheng Z, Ran Z, Wang D, Hoppe AD, Simonson R, Chakravarty S, Hause BM, Li F. Genomic and evolutionary characterization of a novel influenza-C-like virus from swine. Arch Virol 2014; 159:249-55. [PMID: 23942954 PMCID: PMC5714291 DOI: 10.1007/s00705-013-1815-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 06/30/2013] [Indexed: 10/26/2022]
Abstract
We recently described the isolation of a novel influenza virus from swine exhibiting respiratory disease in the United States that is distantly related to human influenza C virus. Based on genetic, biochemical and morphological analysis, the virus was provisionally classified as C/swine/Oklahoma/1334/2011 (C/OK). To further understand the genetics and evolution of this novel pathogen, we performed a comprehensive analysis of its sequence and phylogeny. The results demonstrated that C/OK and human influenza C viruses share a conserved array of predicted functional domains in the viral RNA genome replication and viral entry machinery but vary at key functional sites. Furthermore, our evolutionary analysis showed that homologous genes of C/OK and human influenza C viruses diverged from each other an estimated several hundred to several thousand years ago. Taken together, the findings described in this study support and extend our previous observations that C/OK is a genetically and evolutionarily distinct influenza virus in the family Orthomyxoviridae.
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Affiliation(s)
- Zizhang Sheng
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD, 57007, USA
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21
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Hoppe AD, Scott BL, Welliver TP, Straight SW, Swanson JA. N-way FRET microscopy of multiple protein-protein interactions in live cells. PLoS One 2013; 8:e64760. [PMID: 23762252 PMCID: PMC3675202 DOI: 10.1371/journal.pone.0064760] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 04/17/2013] [Indexed: 11/19/2022] Open
Abstract
Fluorescence Resonance Energy Transfer (FRET) microscopy has emerged as a powerful tool to visualize nanoscale protein-protein interactions while capturing their microscale organization and millisecond dynamics. Recently, FRET microscopy was extended to imaging of multiple donor-acceptor pairs, thereby enabling visualization of multiple biochemical events within a single living cell. These methods require numerous equations that must be defined on a case-by-case basis. Here, we present a universal multispectral microscopy method (N-Way FRET) to enable quantitative imaging for any number of interacting and non-interacting FRET pairs. This approach redefines linear unmixing to incorporate the excitation and emission couplings created by FRET, which cannot be accounted for in conventional linear unmixing. Experiments on a three-fluorophore system using blue, yellow and red fluorescent proteins validate the method in living cells. In addition, we propose a simple linear algebra scheme for error propagation from input data to estimate the uncertainty in the computed FRET images. We demonstrate the strength of this approach by monitoring the oligomerization of three FP-tagged HIV Gag proteins whose tight association in the viral capsid is readily observed. Replacement of one FP-Gag molecule with a lipid raft-targeted FP allowed direct observation of Gag oligomerization with no association between FP-Gag and raft-targeted FP. The N-Way FRET method provides a new toolbox for capturing multiple molecular processes with high spatial and temporal resolution in living cells.
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Affiliation(s)
- Adam D Hoppe
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, South Dakota, United States of America.
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22
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Lin J, Hoppe AD. Uniform total internal reflection fluorescence illumination enables live cell fluorescence resonance energy transfer microscopy. Microsc Microanal 2013; 19:350-9. [PMID: 23472941 DOI: 10.1017/s1431927612014420] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Fluorescence resonance energy transfer (FRET) microscopy is a powerful technique to quantify dynamic protein-protein interactions in live cells. Total internal reflection fluorescence (TIRF) microscopy can selectively excite molecules within about 150 nm of the glass-cell interface. Recently, these two approaches were combined to enable high-resolution FRET imaging on the adherent surface of living cells. Here, we show that interference fringing of the coherent laser excitation used in TIRF creates lateral heterogeneities that impair quantitative TIRF-FRET measurements. We overcome this limitation by using a two-dimensional scan head to rotate laser beams for donor and acceptor excitation around the back focal plane of a high numerical aperture objective. By setting different radii for the circles traced out by each laser in the back focal plane, the penetration depth was corrected for different wavelengths. These modifications quell spatial variations in illumination and permit calibration for quantitative TIRF-FRET microscopy. The capability of TIRF-FRET was demonstrated by imaging assembled cyan and yellow fluorescent protein-tagged HIV-Gag molecules in single virions on the surfaces of living cells. These interactions are shown to be distinct from crowding of HIV-Gag in lipid rafts.
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Affiliation(s)
- Jia Lin
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD 57007, USA
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23
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Hause BM, Ducatez M, Collin EA, Ran Z, Liu R, Sheng Z, Armien A, Kaplan B, Chakravarty S, Hoppe AD, Webby RJ, Simonson RR, Li F. Isolation of a novel swine influenza virus from Oklahoma in 2011 which is distantly related to human influenza C viruses. PLoS Pathog 2013; 9:e1003176. [PMID: 23408893 PMCID: PMC3567177 DOI: 10.1371/journal.ppat.1003176] [Citation(s) in RCA: 233] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 12/19/2012] [Indexed: 12/22/2022] Open
Abstract
Of the Orthomyxoviridae family of viruses, only influenza A viruses are thought to exist as multiple subtypes and has non-human maintenance hosts. In April 2011, nasal swabs were collected for virus isolation from pigs exhibiting influenza-like illness. Subsequent electron microscopic, biochemical, and genetic studies identified an orthomyxovirus with seven RNA segments exhibiting approximately 50% overall amino acid identity to human influenza C virus. Based on its genetic organizational similarities to influenza C viruses this virus has been provisionally designated C/Oklahoma/1334/2011 (C/OK). Phylogenetic analysis of the predicted viral proteins found that the divergence between C/OK and human influenza C viruses was similar to that observed between influenza A and B viruses. No cross reactivity was observed between C/OK and human influenza C viruses using hemagglutination inhibition (HI) assays. Additionally, screening of pig and human serum samples found that 9.5% and 1.3%, respectively, of individuals had measurable HI antibody titers to C/OK virus. C/OK virus was able to infect both ferrets and pigs and transmit to naive animals by direct contact. Cell culture studies showed that C/OK virus displayed a broader cellular tropism than a human influenza C virus. The observed difference in cellular tropism was further supported by structural analysis showing that hemagglutinin esterase (HE) proteins between two viruses have conserved enzymatic but divergent receptor-binding sites. These results suggest that C/OK virus represents a new subtype of influenza C viruses that currently circulates in pigs that has not been recognized previously. The presence of multiple subtypes of co-circulating influenza C viruses raises the possibility of reassortment and antigenic shift as mechanisms of influenza C virus evolution.
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Affiliation(s)
- Ben M. Hause
- Newport Laboratories, Worthington, Minnesota, United States of America
- Department of Veterinary and Biomedical Sciences, South Dakota State University, Brookings, South Dakota, United States of America
| | - Mariette Ducatez
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, United States of America
| | - Emily A. Collin
- Newport Laboratories, Worthington, Minnesota, United States of America
| | - Zhiguang Ran
- Department of Veterinary and Biomedical Sciences, South Dakota State University, Brookings, South Dakota, United States of America
- Department of Biology and Microbiology, South Dakota State University, Brookings, South Dakota, United States of America
| | - Runxia Liu
- Department of Veterinary and Biomedical Sciences, South Dakota State University, Brookings, South Dakota, United States of America
- Department of Biology and Microbiology, South Dakota State University, Brookings, South Dakota, United States of America
| | - Zizhang Sheng
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, South Dakota, United States of America
| | - Anibal Armien
- Veterinary Diagnostic Laboratory, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Bryan Kaplan
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, United States of America
| | - Suvobrata Chakravarty
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, South Dakota, United States of America
| | - Adam D. Hoppe
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, South Dakota, United States of America
| | - Richard J. Webby
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, United States of America
| | - Randy R. Simonson
- Newport Laboratories, Worthington, Minnesota, United States of America
| | - Feng Li
- Department of Veterinary and Biomedical Sciences, South Dakota State University, Brookings, South Dakota, United States of America
- Department of Biology and Microbiology, South Dakota State University, Brookings, South Dakota, United States of America
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24
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Low-Nam ST, Kerkvliet JG, Cheng AT, Drubin DG, Hoppe AD. Polarized-Tirf-Based Monitoring of Sub-Resolution Membrane Curvature Dynamics during Clathrin-Mediated Endocytosis. Biophys J 2013. [DOI: 10.1016/j.bpj.2012.11.3424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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25
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Baruah M, Huntimer ED, Ahmed MS, Hoppe AD, Halaweish FT. Selective BODIPY® based fluorescent chemosensor for imaging Pb2+ ion in living cells. Tetrahedron Lett 2012. [DOI: 10.1016/j.tetlet.2012.05.092] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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26
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Hoppe AD, Kerkvliet J, Lin J. Imaging Subresolution Membrane Curvature in Living Cells by Back Focal Plane Positioning Polarized Total Internal Reflection Microscopy (TIRFM). Biophys J 2012. [DOI: 10.1016/j.bpj.2011.11.3939] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022] Open
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27
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Abstract
Fluorescence resonance energy transfer (FRET) imaging can measure the spatial and temporal distributions of activated Rho GTPases within living cells. This information is essential for understanding how signaling networks influence Rho-GTPase switching and for elucidating the mechanisms of Rho GTPase control of the cytoskeleton. This chapter describes FRET microscopy methods to image the distribution of GTP-bound Rac and Cdc42 during the well-defined morphological transitions of phagocytosis by macrophages. Specifically, we describe the use of FRET microscopy to detect the binding of genetically encoded fluorescent protein fusions to Rac1 or Cdc42 with a fluorescent protein fusion to a p21-binding domain (PBD) that recognizes their GTP-bound states. We focus on quantifying the kinetics and activation levels of Rac and Cdc42 during Fc receptor-mediated phagocytosis by macrophages. This process is a Rac1, Cdc42, and actin-dependent process, by which macrophages engulf particles ranging in size from 0.5 to 20 μm and is an ideal model system for studying the spatial and temporal control of these GTPases. Quantitative FRET analysis for measuring the fractions of activated GTPase to allow comparison between cells, independent of the relative expression levels of the fluorescent fusions is also discussed.
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Affiliation(s)
- Adam D Hoppe
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD, USA.
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28
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Brenner MH, Cai D, Nichols SR, Straight SW, Hoppe AD, Swanson JA, Ogilvie JP. Pulse-shaping multiphoton FRET microscopy. Proc SPIE Int Soc Opt Eng 2012; 8226:82260R. [PMID: 22737295 PMCID: PMC3380370 DOI: 10.1117/12.909225] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Fluorescence Resonance Energy Transfer (FRET) microscopy is a commonly-used technique to study problems in biophysics that range from uncovering cellular signaling pathways to detecting conformational changes in single biomolecules. Unfortunately, excitation and emission spectral overlap between the fluorophores create challenges in quantitative FRET studies. It has been shown previously that quantitative FRET stoichiometry can be performed by selective excitation of donor and acceptor fluorophores. Extending this approach to two-photon FRET applications is difficult when conventional femtosecond laser sources are used due to their limited bandwidth and slow tuning response time. Extremely broadband titanium:sapphire lasers enable the simultaneous excitation of both donor and acceptor for two-photon FRET, but do so without selectivity. Here we present a novel two-photon FRET microscopy technique that employs pulse-shaping to perform selective excitation of fluorophores in live cells and detect FRET between them. Pulse-shaping via multiphoton intrapulse interference can tailor the excitation pulses to achieve selective excitation. This technique overcomes the limitation of conventional femtosecond lasers to allow rapid switching between selective excitation of the donor and acceptor fluorophores. We apply the method to live cells expressing the fluorescent proteins mCerulean and mCherry, demonstrating selective excitation of fluorophores via pulse-shaping and the detection of two-photon FRET. This work paves the way for two-photon FRET stoichiometry.
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Affiliation(s)
- Meredith H. Brenner
- Applied Physics Program, University of Michigan, 450 Church Street, Ann Arbor, MI, USA 48109
| | - Dawen Cai
- Department of Physics, University of Michigan, 450 Church Street, Ann Arbor, MI, USA 48109
| | - Sarah R. Nichols
- Department of Physics, University of Michigan, 450 Church Street, Ann Arbor, MI, USA 48109
| | - Samuel W. Straight
- Center for Live Cell Imaging, University of Michigan Medical School, 1150 West Medical Center Drive, Ann Arbor, MI, USA 48109
- Department of Microbiology and Immunology, University of Michigan Medical School, 1150 West Medical Center Drive, Ann Arbor, MI, USA 48109
| | - Adam D. Hoppe
- Department of Chemistry and Biochemistry, South Dakota State University, Avera Health Science Center, Box 2202, Brookings, SD, USA 57007
| | - Joel A. Swanson
- Department of Microbiology and Immunology, University of Michigan Medical School, 1150 West Medical Center Drive, Ann Arbor, MI, USA 48109
| | - Jennifer P. Ogilvie
- Department of Physics, University of Michigan, 450 Church Street, Ann Arbor, MI, USA 48109
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Abstract
During Fcγ receptor (FcR)-mediated phagocytosis by macrophages, cytoplasm advances over IgG-coated particles by the sequential ligation of FcR in plasma membranes. If FcR signaling was strictly autonomous, then the signals generated during phagocytosis should be proportional to the number of ligated receptors. By measuring FcR-dependent responses to beads coated with various densities of IgG, this study identified nonlinear signaling that organizes an all or none response during particle ingestion. Phagocytosis of beads with IgG at low density either stalled after making small, actin-rich cups or proceeded to completion at the same rate as phagocytosis of high-density IgG beads. Signals were measured by quantifying the recruitment of YFP-labeled probes to phagocytic cup membranes. Although the magnitude of early signals correlated with IgG density, later signals showed an all or none response, which was regulated by the concentrations of 3' phosphoinositides in phagocytic cup membranes. Thus, 3' phosphoinositides, shown previously to be required for phagocytosis, function in a feedback regulatory mechanism affecting late but not early signals. This indicates a mechanism for the coordination of cell movements initiated by receptor signaling.
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Affiliation(s)
| | - Adam D. Hoppe
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109-5620; and
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD 57007-0896
| | - Joel A. Swanson
- Biophysics Program and
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109-5620; and
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30
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Sun X, Fontaine JM, Hoppe AD, Carra S, DeGuzman C, Martin JL, Simon S, Vicart P, Welsh MJ, Landry J, Benndorf R. Abnormal interaction of motor neuropathy-associated mutant HspB8 (Hsp22) forms with the RNA helicase Ddx20 (gemin3). Cell Stress Chaperones 2010; 15:567-82. [PMID: 20157854 PMCID: PMC3006614 DOI: 10.1007/s12192-010-0169-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Revised: 01/07/2010] [Accepted: 01/08/2010] [Indexed: 01/16/2023] Open
Abstract
A number of missense mutations in the two related small heat shock proteins HspB8 (Hsp22) and HspB1 (Hsp27) have been associated with the inherited motor neuron diseases (MND) distal hereditary motor neuropathy and Charcot-Marie-Tooth disease. HspB8 and HspB1 interact with each other, suggesting that these two etiologic factors may act through a common biochemical mechanism. However, their role in neuron biology and in MND is not understood. In a yeast two-hybrid screen, we identified the DEAD box protein Ddx20 (gemin3, DP103) as interacting partner of HspB8. Using co-immunoprecipitation, chemical cross-linking, and in vivo quantitative fluorescence resonance energy transfer, we confirmed this interaction. We also show that the two disease-associated mutant HspB8 forms have abnormally increased binding to Ddx20. Ddx20 itself binds to the survival-of-motor-neurons protein (SMN protein), and mutations in the SMN1 gene cause spinal muscular atrophy, another MND and one of the most prevalent genetic causes of infant mortality. Thus, these protein interaction data have linked the three etiologic factors HspB8, HspB1, and SMN protein, and mutations in any of their genes cause the various forms of MND. Ddx20 and SMN protein are involved in spliceosome assembly and pre-mRNA processing. RNase treatment affected the interaction of the mutant HspB8 with Ddx20 suggesting RNA involvement in this interaction and a potential role of HspB8 in ribonucleoprotein processing.
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Affiliation(s)
- Xiankui Sun
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109 USA
| | - Jean-Marc Fontaine
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109 USA
| | - Adam D. Hoppe
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109 USA
| | - Serena Carra
- Le Centre de recherche en cancérologie, l’Université Laval, L’Hôtel-Dieu de Québec, Laval, Québec Canada G1R 2J6
- Section for Radiation and Stress Cell Biology, Department of Cell Biology, University Medical Center Groningen, 9713 AV Groningen, The Netherlands
| | - Cheryl DeGuzman
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109 USA
| | - Jody L. Martin
- Department of Medicine, Cardiovascular Institute, Loyola University Medical Center, Maywood, IL 60153 USA
| | - Stephanie Simon
- Laboratory BFA, University Paris Diderot/CNRS, 75013 Paris, France
| | - Patrick Vicart
- Laboratory BFA, University Paris Diderot/CNRS, 75013 Paris, France
| | - Michael J. Welsh
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109 USA
| | - Jacques Landry
- Le Centre de recherche en cancérologie, l’Université Laval, L’Hôtel-Dieu de Québec, Laval, Québec Canada G1R 2J6
| | - Rainer Benndorf
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109 USA
- Department of Pediatrics, Ohio State University, Columbus, OH 43205 USA
- The Center for Clinical and Translational Research, The Research Institute at Nationwide Children’s Hospital, Research Building II, Room WA2109, 700 Children’s Drive, Columbus, OH 43205 USA
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31
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Beemiller P, Zhang Y, Mohan S, Levinsohn E, Gaeta I, Hoppe AD, Swanson JA. A Cdc42 activation cycle coordinated by PI 3-kinase during Fc receptor-mediated phagocytosis. Mol Biol Cell 2010; 21:470-80. [PMID: 19955216 PMCID: PMC2814791 DOI: 10.1091/mbc.e08-05-0494] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Revised: 11/09/2008] [Accepted: 11/19/2009] [Indexed: 11/15/2022] Open
Abstract
Fcgamma Receptor (FcR)-mediated phagocytosis by macrophages requires phosphatidylinositol 3-kinase (PI3K) and activation of the Rho-family GTPases Cdc42 and Rac1. Cdc42 is activated at the advancing edge of the phagocytic cup, where actin is concentrated, and is deactivated at the base of the cup. The timing of 3' phosphoinositide (3'PI) concentration changes in cup membranes suggests a role for 3'PIs in deactivation of Cdc42. This study examined the relationships between PI3K and the patterns of Rho-family GTPase signaling during phagosome formation. Inhibition of PI3K resulted in persistently active Cdc42 and Rac1, but not Rac2, in stalled phagocytic cups. Patterns of 3'PIs and Rho-family GTPase activities during phagocytosis of 5- and 2-mum-diameter microspheres indicated similar underlying mechanisms despite particle size-dependent sensitivities to PI3K inhibition. Expression of constitutively active Cdc42(G12V) increased 3'PI concentrations in plasma membranes and small phagosomes, indicating a role for Cdc42 in PI3K activation. Cdc42(G12V) inhibited phagocytosis at a later stage than inhibition by dominant negative Cdc42(N17). Together, these studies identified a Cdc42 activation cycle organized by PI3K, in which FcR-activated Cdc42 stimulates PI3K and actin polymerization, and the subsequent increase of 3'PIs in cup membranes inactivates Cdc42 to allow actin recycling necessary for phagosome formation.
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Affiliation(s)
| | - Youxin Zhang
- Biophysics Graduate Program, University of Michigan, Ann Arbor, MI 48109-1055
| | - Suresh Mohan
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109-5620; and
| | - Erik Levinsohn
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109-5620; and
| | - Isabella Gaeta
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109-5620; and
| | - Adam D. Hoppe
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109-5620; and
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD 57007-0896
| | - Joel A. Swanson
- *Cellular and Molecular Biology Graduate Program, and
- Biophysics Graduate Program, University of Michigan, Ann Arbor, MI 48109-1055
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109-5620; and
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32
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Mehta K, Hoppe AD, Kainkaryam R, Woolf PJ, Linderman JJ. A computational approach to inferring cellular protein-binding affinities from quantitative fluorescence resonance energy transfer imaging. Proteomics 2009; 9:5371-83. [PMID: 19834887 DOI: 10.1002/pmic.200800494] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2008] [Accepted: 09/01/2009] [Indexed: 12/22/2022]
Abstract
Fluorescence resonance energy transfer (FRET) microscopy can measure the spatial distribution of protein interactions inside live cells. Such experiments give rise to complex data sets with many images of single cells, motivating data reduction and abstraction. In particular, determination of the value of the equilibrium dissociation constant (K(d)) will provide a quantitative measure of protein-protein interactions, which is essential to reconstructing cellular signaling networks. Here, we investigate the feasibility of using quantitative FRET imaging of live cells to estimate the local value of K(d) for two interacting labeled molecules. An algorithm is developed to infer the values of K(d) using the intensity of individual voxels of 3-D FRET microscopy images. The performance of our algorithm is investigated using synthetic test data, both in the absence and in the presence of endogenous (unlabeled) proteins. The influence of optical blurring caused by the microscope (confocal or wide field) and detection noise on the accuracy of K(d) inference is studied. We show that deconvolution of images followed by analysis of intensity data at local level can improve the estimate of K(d). Finally, the performance of this algorithm using cellular data on the interaction between yellow fluorescent protein-Rac and cyan fluorescent protein-PBD in mammalian cells is shown.
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Affiliation(s)
- Khamir Mehta
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109-2136, USA
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33
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Yoshida S, Hoppe AD, Araki N, Swanson JA. Sequential signaling in plasma-membrane domains during macropinosome formation in macrophages. J Cell Sci 2009; 122:3250-61. [PMID: 19690049 PMCID: PMC2736863 DOI: 10.1242/jcs.053207] [Citation(s) in RCA: 126] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/21/2009] [Indexed: 12/17/2022] Open
Abstract
Macropinosomes are large endocytic vesicles that form in ruffling regions of plasma membrane. To analyze signal organization relative to ruffle closure into circular ruffles and cup closure into macropinosomes, this study used quantitative microscopy to measure 3' phosphoinositides and small-GTPase activities in a representative subset of forming macropinosomes. Macropinocytosis was stimulated by the addition of macrophage colony-stimulating factor (M-CSF) to macrophages expressing fluorescent reporter proteins. Ratiometric and fluorescence resonance energy transfer (FRET) microscopy determined that Rac1 activity and phosphatidylinositol (3,4,5)-trisphosphate [PtdIns(3,4,5)P(3)] levels increased transiently, peaking 26-30 seconds after ruffle closure. Three-dimensional reconstruction of cells labeled with the fluorescent dye FM4-64 showed that PtdIns(3,4,5)P(3) was restricted to open, circular cups in the plasma membrane. Quantitative fluorescence microscopic methods determined the timing of cup closure, which followed 40-100 seconds after Rac1 and PtdIns(3,4,5)P(3) deactivation and coincided with accumulation of phosphatidylinositol 3-phosphate and Rab5a. Thus, ruffle closure creates a circular domain of plasma membrane that localizes the activation and deactivation of Rac1 and phosphoinositide 3-kinase (PI3K), followed by recruitment of Rab5a and the contractile activities of cup closure.
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Affiliation(s)
- Sei Yoshida
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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34
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Abstract
Advances in microscopy and fluorescent probes provide new insight into the nanometer-scale biochemistry governing the interactions between eukaryotic cells and pathogens. When combined with mathematical modelling, these new technologies hold the promise of qualitative, quantitative and predictive descriptions of these pathways. Using the light microscope to study the spatial and temporal relationships between pathogens, host cells and their respective biochemical machinery requires an appreciation for how fluorescent probes and imaging devices function. This review summarizes how live cell fluorescence microscopy with common instruments can provide quantitative insight into the cellular and molecular functions of hosts and pathogens.
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Affiliation(s)
- Adam D Hoppe
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD 57007-0896, USA.
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35
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Hoppe AD, Shorte SL, Swanson JA, Heintzmann R. Three-dimensional FRET reconstruction microscopy for analysis of dynamic molecular interactions in live cells. Biophys J 2008; 95:400-18. [PMID: 18339754 PMCID: PMC2426648 DOI: 10.1529/biophysj.107.125385] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2007] [Accepted: 02/22/2008] [Indexed: 11/18/2022] Open
Abstract
Analysis of cellular pathways requires concentration measurements of dynamically interacting molecules within the three-dimensional (3D) space of single living cells. Förster resonance energy transfer (FRET) microscopy from widefield, from confocal, and potentially from superresolution microscopes can access this information; however, these measurements are distorted by the inherent 3D blurring of optical imaging, spectral overlap of fluorophores, and detection noise. We propose a mathematical model of these processes and demonstrate, through simulation, how these distortions limit the dynamic range and sensitivity of conventional FRET microscopy. Using this model, we devise and validate a new approach (called 3D-FRET stoichiometry reconstruction, 3DFSR) for reconstructing 3D distributions of bound and free fluorescent molecules. Previous attempts to reconstruct 3D-FRET data relied on sequential spectral unmixing and deconvolution, a process that corrupts the detection statistics. We demonstrate that 3DFSR is superior to these approaches since it simultaneously models spectral mixing, optical blurring, and detection noise. To achieve the full potential of this technique, we developed an instrument capable of acquiring 3D-FRET data rapidly and sensitively from single living cells. Compared with conventional FRET microscopy, our 3D-FRET reconstruction technique and new instrumentation provides orders of magnitude gains in both sensitivity and accuracy wherein sustained high-resolution four-dimensional (x,y,z,t) imaging of molecular interactions inside living cells was achieved. These results verify previous observations that Cdc42 signaling is localized to the advancing margins of forming phagosomes in macrophages.
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Affiliation(s)
- Adam D Hoppe
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
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36
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Fuller RS, Abazeed ME, Hoppe AD, Zhang X, Kumar A. Gga/Clathrin‐Dependent Transport from the TGN to the Late Endosome/Prevacuolar Compartment. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.628.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - Adam D. Hoppe
- Biological Chemistry
- Microbiology & ImmunologyUniversity of Michigan Medical SchoolAnn ArborMI
| | - Xuefeng Zhang
- MolecularCellular and Developmental BiologyUniversity of MichiganAnn ArborMI
- Life Sciences Institute
| | - Anuj Kumar
- MolecularCellular and Developmental BiologyUniversity of MichiganAnn ArborMI
- Life Sciences Institute
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37
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Abstract
Macroautophagy involves lysosomal/vacuolar elimination of long-lived proteins and entire organelles from the cytosol. The process begins with formation of a double-membrane vesicle that sequesters bulk cytoplasm, or a specific cargo destined for lysosomal/vacuolar delivery. The completed vesicle fuses with the lysosome/vacuole limiting membrane, releasing its content into the organelle lumen for subsequent degradation and recycling of the resulting macromolecules. A majority of the autophagy-related (Atg) proteins are required at the step of vesicle formation. The integral membrane protein Atg9 cycles between certain intracellular compartments and the vesicle nucleation site, presumably to supply membranes necessary for macroautophagic vesicle formation. In this study we have tracked the movement of Atg9 over time in living cells by using real-time fluorescence microscopy. Our results reveal that an actin-related protein, Arp2, briefly colocalizes with Atg9 and directly regulates the dynamics of Atg9 movement. We propose that proteins of the Arp2/3 complex regulate Atg9 transport for specific types of autophagy.
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Affiliation(s)
- Iryna Monastyrska
- Life Sciences Institute and Departments of Molecular, Cellular, University of Michigan, Ann Arbor, MI 48109, USA
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38
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Abstract
Three mutations (R120G, Q151X, and 464delCT) in the small heat shock protein alphaB-crystallin cause inherited myofibrillar myopathy. In an effort to elucidate the molecular basis for the associated myopathy, we have determined the following for these mutant alphaB-crystallin proteins: (i) the formation of aggregates in transfected cells; (ii) the partition into different subcellular fractions; (iii) the phosphorylation status; and (iv) the ability to interact with themselves, with wild-typealphaB-crystallin, and with other small heat shock proteins that are abundant in muscles. We found that all three alphaB-crystallin mutants have an increased tendency to form cytoplasmic aggregates in transfected cells and significantly increased levels of phosphorylation when compared with the wild-type protein. Although wild-type alphaB-crystallin partitioned essentially into the cytosol and membranes/organelles fractions, mutant alphaB-crystallin proteins partitioned additionally into the nuclear and cytoskeletal fractions. By using various protein interaction assays, including quantitative fluorescence resonance energy transfer measurements in live cells, we found abnormal interactions of the various alphaB-crystallin mutants with wild-type alphaB-crystallin, with themselves, and with the other small heat shock proteins Hsp20, Hsp22, and possibly with Hsp27. The collected data suggest that eachalphaB-crystallin mutant has a unique pattern of abnormal interaction properties. These distinct properties of the alphaB-crystallin mutants identified are likely to contribute to a better understanding of the gradual manifestation and clinical heterogeneity of the associated myopathy in patients.
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Affiliation(s)
- Stephanie Simon
- EA300 Stress et Pathologies du Cytosquelette, Université Paris 7, UFR de Biochimie, Paris, France
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39
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Seveau S, Tham TN, Payrastre B, Hoppe AD, Swanson JA, Cossart P. A FRET analysis to unravel the role of cholesterol in Rac1 and PI 3-kinase activation in the InlB/Met signalling pathway. Cell Microbiol 2007; 9:790-803. [PMID: 17140407 DOI: 10.1111/j.1462-5822.2006.00832.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The signalling pathway for the hepatocyte growth factor receptor, Met/HGF-R, is hijacked by the bacterial surface protein InlB to induce Listeria monocytogenes entry into non-phagocytic cells. We previously showed that Listeria invades host cells by interacting with specialized microdomains of the host plasma membrane called lipid rafts. In this study, we analysed in living cells signalling events that are crucial for Listeria entry using a fluorescence resonance energy transfer-based microscopic method. Phosphoinositide (PI) 3-kinase activity and Rac1 signalling induced by Listeria interacting with epithelial cells were monitored as well as signalling induced by soluble InlB and the Met natural ligand HGF. We found that InlB and HGF induced similar kinetics of PI 3-kinase and Rac1 activation. PI 3-kinase activation was upstream and independent of Rac1 activation. Cholesterol-depletion experiments were performed to address the role of lipid rafts in Met signalling. The amount of 3'-phosphoinositides produced by PI 3-kinase was not affected by cholesterol depletion, while their membrane dynamic was cholesterol-dependent. Rac1 activation, downstream from PI 3-kinase, was cholesterol-dependent suggesting that the spatial distribution of 3'-phosphoinositides within membrane microdomains is critical for Rac1 activation and consequently for F-actin assembly at bacterial entry site.
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Affiliation(s)
- Stéphanie Seveau
- Institute Pasteur, Unité des Interactions Bactéries-Cellules, Paris, France
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40
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Cai D, Hoppe AD, Swanson JA, Verhey KJ. Kinesin-1 structural organization and conformational changes revealed by FRET stoichiometry in live cells. J Cell Biol 2007; 176:51-63. [PMID: 17200416 PMCID: PMC2063625 DOI: 10.1083/jcb.200605097] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2006] [Accepted: 12/01/2006] [Indexed: 11/22/2022] Open
Abstract
Kinesin motor proteins drive the transport of cellular cargoes along microtubule tracks. How motor protein activity is controlled in cells is unresolved, but it is likely coupled to changes in protein conformation and cargo association. By applying the quantitative method fluorescence resonance energy transfer (FRET) stoichiometry to fluorescent protein (FP)-labeled kinesin heavy chain (KHC) and kinesin light chain (KLC) subunits in live cells, we studied the overall structural organization and conformation of Kinesin-1 in the active and inactive states. Inactive Kinesin-1 molecules are folded and autoinhibited such that the KHC tail blocks the initial interaction of the KHC motor with the microtubule. In addition, in the inactive state, the KHC motor domains are pushed apart by the KLC subunit. Thus, FRET stoichiometry reveals conformational changes of a protein complex in live cells. For Kinesin-1, activation requires a global conformational change that separates the KHC motor and tail domains and a local conformational change that moves the KHC motor domains closer together.
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Affiliation(s)
- Dawen Cai
- Biophysics Research Division, University of Michigan, Ann Arbor, MI 48109, USA
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Fontaine JM, Sun X, Hoppe AD, Simon S, Vicart P, Welsh MJ, Benndorf R. Abnormal small heat shock protein interactions involving neuropathy‐associated HSP22 (HSPB8) mutants. FASEB J 2006; 20:2168-70. [PMID: 16935933 DOI: 10.1096/fj.06-5911fje] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Two mutations (K141E, K141N) in the small heat shock protein (sHSP) HSP22 (HSPB8) are associated with the inherited peripheral motor neuron disorders distal hereditary motor neuropathy type II and axonal Charcot-Marie-Tooth disease type 2L. HSP22 is known to form homodimers, heterodimers with other sHSPs, and larger oligomers. In an effort to elucidate the cellular basis for these diseases, we have determined the ability of mutant HSP22 to interact with itself, with wild-type HSP22, and with other sHSPs that are abundant in neurons. Using the yeast two-hybrid method, quantitative fluorescence resonance energy transfer in live cells, and cross-linking, we found aberrantly increased interactions of mutant HSP22 forms with themselves, with wild-type HSP22, and with the other sHSPs, alphaB-crystallin, and HSP27. Interaction with HSP20 was not affected by the mutations. The data suggest that each mutant form of HSP22 has a characteristic pattern of abnormal interaction properties. A mutation (S135F) in HSP27 that is also associated with these disorders showed increased interaction with wild-type HSP22 also, suggesting linkage of these two etiologic factors, HSP22 and HSP27, into one common pathway. Increased interactions involving mutant sHSPs may be the molecular basis for their increased tendency to form cytoplasmic protein aggregates, and for the occurrence of the associated neuropathies.
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Affiliation(s)
- Jean-Marc Fontaine
- Department of Cell and Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Pl., Ann Arbor, MI 48109-2200, USA
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42
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Beemiller P, Hoppe AD, Swanson JA. A phosphatidylinositol-3-kinase-dependent signal transition regulates ARF1 and ARF6 during Fcgamma receptor-mediated phagocytosis. PLoS Biol 2006; 4:e162. [PMID: 16669702 PMCID: PMC1457017 DOI: 10.1371/journal.pbio.0040162] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2005] [Accepted: 03/17/2006] [Indexed: 01/20/2023] Open
Abstract
Fcgamma receptor (FcgammaR)-mediated phagocytosis of IgG-coated particles is regulated by 3'-phosphoinositides (3'PIs) and several classes of small GTPases, including ARF6 from the ADP Ribosylation Factor subfamily. The insensitivity of phagocytosis to brefeldin A (BFA), an inhibitor of certain ARF guanine nucleotide exchange factors (GEFs), previously indicated that ARF1 did not participate in phagocytosis. In this study, we show that ARF1 was activated during FcgammaR-mediated phagocytosis and that blocking normal ARF1 cycling inhibited phagosome closure. We examined the distributions and activation patterns of ARF6 and ARF1 during FcgammaR-mediated phagocytosis using fluorescence resonance energy transfer (FRET) stoichiometric microscopy of macrophages expressing CFP- or YFP-chimeras of ARF1, ARF6, and a GTP-ARF-binding protein domain. Both GTPases were activated by BFA-insensitive factors at sites of phagocytosis. ARF6 activation was restricted to the leading edge of the phagocytic cup, while ARF1 activation was delayed and delocalized over the phagosome. Phagocytic cups formed after inhibition of PI 3-kinase (PI-3K) contained persistently activated ARF6 and minimally activated ARF1. This indicates that a PI-3K-dependent signal transition defines the sequence of ARF GTPase activation during phagocytosis and that ARF6 and ARF1 coordinate different functions at the forming phagosome.
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Affiliation(s)
- Peter Beemiller
- 1Cellular and Molecular Biology Graduate Program, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Adam D Hoppe
- 2Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Joel A Swanson
- 1Cellular and Molecular Biology Graduate Program, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- 2Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
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Shaughnessy LM, Hoppe AD, Christensen KA, Swanson JA. Membrane perforations inhibit lysosome fusion by altering pH and calcium in Listeria monocytogenes vacuoles. Cell Microbiol 2006; 8:781-92. [PMID: 16611227 PMCID: PMC1435990 DOI: 10.1111/j.1462-5822.2005.00665.x] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Listeria monocytogenes (Lm) evade microbicidal defences inside macrophages by secreting a pore-forming cytolysin listeriolysin O (LLO), which allows Lm to escape vacuoles. LLO also inhibits Lm vacuole fusion with lysosomes, which indicates LLO alters vacuole chemistry prior to release of Lm into cytoplasm. Using fluorescent probes to measure membrane permeability, calcium and pH, we identified small membrane perforations in vacuoles containing wild-type but not LLO-deficient (hly-) Lm. The small membrane perforations released small fluorescent molecules and persisted for several minutes before expanding to allow exchange of larger fluorescent molecules. Macropinosomes and hly- Lm vacuoles acidified and increased their calcium content ([Ca2+]vac) within minutes of formation; however, the small perforations made by LLO-expressing bacteria increased vacuolar pH and decreased [Ca2+]vac shortly after infection. Experimental increases in vacuolar pH inhibited Lm vacuole fusion with lysosomes. The timing of perforation indicated that LLO-dependent delays of Lm vacuole maturation result from disruption of ion gradients across vacuolar membranes.
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Affiliation(s)
- Lee M. Shaughnessy
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109-0620, USA
| | - Adam D. Hoppe
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109-0620, USA
| | | | - Joel A. Swanson
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109-0620, USA
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Abstract
Current methods for fluorescence resonance energy transfer (FRET) microscopy of living cells involve taking a series of images with alternating excitation colors in separate camera exposures. Here we present a new FRET method based on polarization that requires only one camera exposure and thereby offers the possibility for better time resolution of dynamic associations among subcellular components. Polarized FRET (p-FRET) uses a simultaneous combination of excitation wavelengths from two orthogonally polarized sources, along with an emission channel tri-image splitter outfitted with appropriate polarizers, to concurrently excite and collect fluorescence from free donors, free acceptors, and FRET pairs. Based upon the throughput in each emission channel as premeasured on pure samples of each of the three species, decoupling of an unknown sample's three polarized fluorescence images can be performed to calculate the pixel-by-pixel concentrations of donor, acceptor, and FRET pairs. The theory of this approach is presented here, and its feasibility is experimentally confirmed by measurements on mixtures of cyan fluorescent protein (CFP), citrine ((Cit) a yellow fluorescent protein variant), and linked fusion proteins (CFP-L16-Cit, CFP-L7-Cit, CFP-L54-Cit) in living cells. The effects of shot noise, acceptor polarization, and FRET efficiency on the statistical accuracy of p-FRET experimental results are investigated by a noise-simulation program.
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Affiliation(s)
- Alexa L Mattheyses
- Biophysics Research Division, Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan 48109, USA.
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Abstract
Phagocytosis by macrophages can be initiated by Fcgamma receptors (FcR) in membranes that bind to Fc regions of immunoglobulin G (IgG). Activated FcR transduce signals to cytoplasm, which regulate the internalization of IgG-coated particles into plasma membrane-derived vacuoles, phagosomes. Particles internalized by phagocytosis are much larger than FcR, which prompts questions of if and how the receptors are coordinated with each other. FcR-mediated signal transduction entails recruitment of proteins from cytoplasm to the receptor, largely via protein phosphorylation. These FcR signaling complexes then activate proteins that regulate actin, myosin, membrane fusion, and the production of reactive oxygen intermediates. Recent fluorescence microscopic studies of phagocytosis in macrophages indicate that signaling by FcR occurs as a sequence of distinct stages, evident in the spatial and temporal patterns of phosphoinositides, protein kinase C, and Rho-family GTPase activation on forming phagosomes. The coordination of these stages may be regulated by lipids or lipid-anchored proteins, which diffuse away from FcR complexes. Lateral diffusion of FcR-derived signals could integrate FcR-dependent responses over large areas of membrane in the forming phagosome.
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Affiliation(s)
- Joel A Swanson
- University of Michigan Medical School, 1335 Catherine Street, Med Sci II, Rm. 5608, Ann Arbor, MI 48109-0620, USA.
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Hoppe AD, Swanson JA. Cdc42, Rac1, and Rac2 display distinct patterns of activation during phagocytosis. Mol Biol Cell 2004; 15:3509-19. [PMID: 15169870 PMCID: PMC491814 DOI: 10.1091/mbc.e03-11-0847] [Citation(s) in RCA: 273] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2003] [Revised: 05/03/2004] [Accepted: 05/04/2004] [Indexed: 01/09/2023] Open
Abstract
The small G proteins Cdc42, Rac1, and Rac2 regulate the rearrangements of actin and membrane necessary for Fcgamma receptor-mediated phagocytosis by macrophages. Activated, GTP-bound Cdc42, Rac1, and Rac2 bind to the p21-binding domain (PBD) of PAK1, and this interaction provided a basis for microscopic methods to localize activation of these G proteins inside cells. Fluorescence resonance energy transfer-based stoichiometry of fluorescent chimeras of actin, PBD, Cdc42, Rac1, and Rac2 was used to quantify G protein activation relative to actin movements during phagocytosis of IgG-opsonized erythrocytes. The activation dynamics of endogenous G proteins, localized using yellow fluorescent protein-labeled PBD, was restricted to phagocytic cups, with a prominent spike of activation over an actin-poor region at the base of the cup. Refinements of fluorescence resonance energy transfer stoichiometry allowed calculation of the fractions of activated GTPases in forming phagosomes. Cdc42 activation was restricted to the leading margin of the cell, whereas Rac1 was active throughout the phagocytic cup. During phagosome closure, activation of Rac1 and Rac2 increased uniformly and transiently in the actin-poor region of phagosomal membrane. These distinct roles for Cdc42, Rac1, and Rac2 in the component activities of phagocytosis indicate mechanisms by which their differential regulation coordinates rearrangements of actin and membranes.
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Affiliation(s)
- Adam D Hoppe
- Department of Microbiology and Immunology and the Biophysics Research Division, University of Michigan Medical School, Ann Arbor, Michigan 48109-0620, USA
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47
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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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