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Antona A, Leo G, Favero F, Varalda M, Venetucci J, Faletti S, Todaro M, Mazzucco E, Soligo E, Saglietti C, Stassi G, Manfredi M, Pelicci G, Corà D, Valente G, Capello D. Targeting lysine-specific demethylase 1 (KDM1A/LSD1) impairs colorectal cancer tumorigenesis by affecting cancer cells stemness, motility, and differentiation. Cell Death Discov 2023; 9:201. [PMID: 37385999 DOI: 10.1038/s41420-023-01502-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 05/12/2023] [Accepted: 06/19/2023] [Indexed: 07/01/2023] Open
Abstract
Among all cancers, colorectal cancer (CRC) is the 3rd most common and the 2nd leading cause of death worldwide. New therapeutic strategies are required to target cancer stem cells (CSCs), a subset of tumor cells highly resistant to present-day therapy and responsible for tumor relapse. CSCs display dynamic genetic and epigenetic alterations that allow quick adaptations to perturbations. Lysine-specific histone demethylase 1A (KDM1A also known as LSD1), a FAD-dependent H3K4me1/2 and H3K9me1/2 demethylase, was found to be upregulated in several tumors and associated with a poor prognosis due to its ability to maintain CSCs staminal features. Here, we explored the potential role of KDM1A targeting in CRC by characterizing the effect of KDM1A silencing in differentiated and CRC stem cells (CRC-SCs). In CRC samples, KDM1A overexpression was associated with a worse prognosis, confirming its role as an independent negative prognostic factor of CRC. Consistently, biological assays such as methylcellulose colony formation, invasion, and migration assays demonstrated a significantly decreased self-renewal potential, as well as migration and invasion potential upon KDM1A silencing. Our untargeted multi-omics approach (transcriptomic and proteomic) revealed the association of KDM1A silencing with CRC-SCs cytoskeletal and metabolism remodeling towards a differentiated phenotype, supporting the role of KDM1A in CRC cells stemness maintenance. Also, KDM1A silencing resulted in up-regulation of miR-506-3p, previously reported to play a tumor-suppressive role in CRC. Lastly, loss of KDM1A markedly reduced 53BP1 DNA repair foci, implying the involvement of KDM1A in the DNA damage response. Overall, our results indicate that KDM1A impacts CRC progression in several non-overlapping ways, and therefore it represents a promising epigenetic target to prevent tumor relapse.
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Affiliation(s)
- Annamaria Antona
- Department of Translational Medicine, Centre of Excellence in Aging Sciences, Università del Piemonte Orientale, Via Solaroli 17, 28100, Novara, Italy.
| | - Giovanni Leo
- Department of Translational Medicine, Centre of Excellence in Aging Sciences, Università del Piemonte Orientale, Via Solaroli 17, 28100, Novara, Italy
| | - Francesco Favero
- Department of Translational Medicine, Centre of Excellence in Aging Sciences, Università del Piemonte Orientale, Via Solaroli 17, 28100, Novara, Italy
- Center for Translational Research on Autoimmune and Allergic Diseases, Department of Translational Medicine, Università del Piemonte Orientale, Corso Trieste 15/A, 28100, Novara, Italy
| | - Marco Varalda
- Department of Translational Medicine, Centre of Excellence in Aging Sciences, Università del Piemonte Orientale, Via Solaroli 17, 28100, Novara, Italy
| | - Jacopo Venetucci
- Department of Translational Medicine, Centre of Excellence in Aging Sciences, Università del Piemonte Orientale, Via Solaroli 17, 28100, Novara, Italy
| | - Stefania Faletti
- Department of Experimental Oncology, IRCCS, European Institute of Oncology, Via Adamello 16, 20139, Milano, Italy
| | - Matilde Todaro
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties (PROMISE), University of Palermo, Piazza delle Cliniche 2, 90127, Palermo, Italy
| | - Eleonora Mazzucco
- Department of Translational Medicine, Centre of Excellence in Aging Sciences, Università del Piemonte Orientale, Via Solaroli 17, 28100, Novara, Italy
| | - Enrica Soligo
- Pathology Unit, Ospedale Sant'Andrea, Corso Mario Abbiate 21, 13100, Vercelli, Italy
| | - Chiara Saglietti
- Department of Translational Medicine, Centre of Excellence in Aging Sciences, Università del Piemonte Orientale, Via Solaroli 17, 28100, Novara, Italy
| | - Giorgio Stassi
- Department of Surgical, Oncological and Stomatological Sciences, Università di Palermo, Via del Vespro 131, 90127, Palermo, Italy
| | - Marcello Manfredi
- Department of Translational Medicine, Centre of Excellence in Aging Sciences, Università del Piemonte Orientale, Via Solaroli 17, 28100, Novara, Italy
- Center for Translational Research on Autoimmune and Allergic Diseases, Department of Translational Medicine, Università del Piemonte Orientale, Corso Trieste 15/A, 28100, Novara, Italy
| | - Giuliana Pelicci
- Department of Translational Medicine, Centre of Excellence in Aging Sciences, Università del Piemonte Orientale, Via Solaroli 17, 28100, Novara, Italy
- Department of Experimental Oncology, IRCCS, European Institute of Oncology, Via Adamello 16, 20139, Milano, Italy
| | - Davide Corà
- Department of Translational Medicine, Centre of Excellence in Aging Sciences, Università del Piemonte Orientale, Via Solaroli 17, 28100, Novara, Italy
- Center for Translational Research on Autoimmune and Allergic Diseases, Department of Translational Medicine, Università del Piemonte Orientale, Corso Trieste 15/A, 28100, Novara, Italy
| | - Guido Valente
- Department of Translational Medicine, Centre of Excellence in Aging Sciences, Università del Piemonte Orientale, Via Solaroli 17, 28100, Novara, Italy
- Pathology Unit, Ospedale Sant'Andrea, Corso Mario Abbiate 21, 13100, Vercelli, Italy
| | - Daniela Capello
- Department of Translational Medicine, Centre of Excellence in Aging Sciences, Università del Piemonte Orientale, Via Solaroli 17, 28100, Novara, Italy
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Cherkashin AP, Rogachevskaja OA, Khokhlov AA, Kabanova NV, Bystrova MF, Kolesnikov SS. Contribution of TRPC3-mediated Ca 2+ entry to taste transduction. Pflugers Arch 2023:10.1007/s00424-023-02834-8. [PMID: 37369785 DOI: 10.1007/s00424-023-02834-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 05/19/2023] [Accepted: 06/22/2023] [Indexed: 06/29/2023]
Abstract
The current concept of taste transduction implicates the TASR/PLCβ2/IP3R3/TRPM5 axis in mediating chemo-electrical coupling in taste cells of the type II. While generation of IP3 has been verified as an obligatory step, DAG appears to be a byproduct of PIP2 cleavage by PLCβ2. Here, we provide evidence that DAG-signaling could play a significant and not yet recognized role in taste transduction. In particular, we found that DAG-gated channels are functional in type II cells but not in type I and type III cells. The DAG-gated current presumably constitutes a fraction of the generator current triggered by taste stimulation in type II cells. Bitter stimuli and DAG analogs produced Ca2+ transients in type II cells, which were greatly decreased at low bath Ca2+, indicating their dependence on Ca2+ influx. Among DAG-gated channels, transcripts solely for TRPC3 were detected in the taste tissue, thus implicating this channel in mediating DAG-regulated Ca2+ entry. Release of the afferent neurotransmitter ATP from CV papillae was monitored online by using the luciferin/luciferase method and Ussing-like chamber. It was shown that ATP secretion initiated by bitter stimuli and DAG analogs strongly depended on mucosal Ca2+. Based on the overall findings, we speculate that in taste transduction, IP3-driven Ca2+ release is transient and mainly responsible for rapid activation of Ca2+-gated TRPM5 channels, thus forming the initial phase of receptor potential. DAG-regulated Ca2+ entry through apically situated TRPC3 channels extends the primary Ca2+ signal and preserves TRPM5 activity, providing a needful prolongation of the receptor potential.
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Affiliation(s)
- Alexander P Cherkashin
- Institute of Cell Biophysics, Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, 3 Institutskaya Street, Pushchino, Moscow Region, 142290, Russia
| | - Olga A Rogachevskaja
- Institute of Cell Biophysics, Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, 3 Institutskaya Street, Pushchino, Moscow Region, 142290, Russia
| | - Alexander A Khokhlov
- Institute of Cell Biophysics, Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, 3 Institutskaya Street, Pushchino, Moscow Region, 142290, Russia
| | - Natalia V Kabanova
- Institute of Cell Biophysics, Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, 3 Institutskaya Street, Pushchino, Moscow Region, 142290, Russia
| | - Marina F Bystrova
- Institute of Cell Biophysics, Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, 3 Institutskaya Street, Pushchino, Moscow Region, 142290, Russia
| | - Stanislav S Kolesnikov
- Institute of Cell Biophysics, Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, 3 Institutskaya Street, Pushchino, Moscow Region, 142290, Russia.
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Sharkova M, Chow E, Erickson T, Hocking JC. The morphological and functional diversity of apical microvilli. J Anat 2023; 242:327-353. [PMID: 36281951 PMCID: PMC9919547 DOI: 10.1111/joa.13781] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 10/03/2022] [Accepted: 10/05/2022] [Indexed: 11/30/2022] Open
Abstract
Sensory neurons use specialized apical processes to perceive external stimuli and monitor internal body conditions. The apical apparatus can include cilia, microvilli, or both, and is adapted for the functions of the particular cell type. Photoreceptors detect light through a large, modified cilium (outer segment), that is supported by a surrounding ring of microvilli-like calyceal processes (CPs). Although first reported 150 years ago, CPs remain poorly understood. As a basis for future study, we therefore conducted a review of existing literature about sensory cell microvilli, which can act either as the primary sensory detector or as support for a cilia-based detector. While all microvilli are finger-like cellular protrusions with an actin core, the processes vary across cell types in size, number, arrangement, dynamics, and function. We summarize the current state of knowledge about CPs and the characteristics of the microvilli found on inner ear hair cells (stereocilia) and cerebral spinal fluid-contacting neurons, with comparisons to the brush border of the intestinal and renal epithelia. The structure, stability, and dynamics of the actin core are regulated by a complement of actin-binding proteins, which includes both common components and unique features when compared across cell types. Further, microvilli are often supported by lateral links, a glycocalyx, and a defined extracellular matrix, each adapted to the function and environment of the cell. Our comparison of microvillar features will inform further research into how CPs support photoreceptor function, and also provide a general basis for investigations into the structure and functions of apical microvilli found on sensory neurons.
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Affiliation(s)
- Maria Sharkova
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Erica Chow
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Timothy Erickson
- Department of Biology, University of New Brunswick, Fredericton, New Brunswick, Canada
| | - Jennifer C Hocking
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.,Division of Anatomy, Department of Surgery, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.,Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.,Women and Children's Health Research Institute, University of Alberta, Edmonton, Alberta, Canada
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Felipe-López A, Hansmeier N, Danzer C, Hensel M. Manipulation of microvillar proteins during Salmonella enterica invasion results in brush border effacement and actin remodeling. Front Cell Infect Microbiol 2023; 13:1137062. [PMID: 36936760 PMCID: PMC10018140 DOI: 10.3389/fcimb.2023.1137062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 02/10/2023] [Indexed: 03/06/2023] Open
Abstract
Enterocyte invasion by the gastrointestinal pathogen Salmonella enterica is accompanied by loss of brush border and massive remodeling of the actin cytoskeleton, leading to microvilli effacement and formation of membrane ruffles. These manipulations are mediated by effector proteins translocated by the Salmonella Pathogenicity Island 1-encoded type III secretion system (SPI1-T3SS). To unravel the mechanisms of microvilli effacement and contribution of SPI1-T3SS effector proteins, the dynamics of host-pathogen interactions was analyzed using live cell imaging (LCI) of polarized epithelial cells (PEC) expressing LifeAct-GFP. PEC were infected with S. enterica wild-type and mutant strains with defined defects in SPI1-T3SS effector proteins, and pharmacological inhibition of actin assembly were applied. We identified that microvilli effacement involves two distinct mechanisms: i) F-actin depolymerization mediated by villin and ii), the consumption of cytoplasmic G-actin by formation of membrane ruffles. By analyzing the contribution of individual SPI1-T3SS effector proteins, we demonstrate that SopE dominantly triggers microvilli effacement and formation of membrane ruffles. Furthermore, SopE via Rac1 indirectly manipulates villin, which culminates in F-actin depolymerization. Collectively, these results indicate that SopE has dual functions during F-actin remodeling in PEC. While SopE-Rac1 triggers F-actin polymerization and ruffle formation, activation of PLCγ and villin by SopE depolymerizes F-actin in PEC. These results demonstrate the key role of SopE in destruction of the intestinal barrier during intestinal infection by Salmonella.
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Affiliation(s)
| | | | - Claudia Danzer
- Mikrobiologisches Institut, Universitätsklinikum Erlangen, Erlangen, Germany
| | - Michael Hensel
- Abt. Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
- *Correspondence: Michael Hensel,
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5
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Engevik MA, Engevik AC. Myosins and membrane trafficking in intestinal brush border assembly. Curr Opin Cell Biol 2022; 77:102117. [PMID: 35870341 DOI: 10.1016/j.ceb.2022.102117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Revised: 06/15/2022] [Accepted: 06/23/2022] [Indexed: 11/29/2022]
Abstract
Myosins are a class of motors that participate in a wide variety of cellular functions including organelle transport, cell adhesion, endocytosis and exocytosis, movement of RNA, and cell motility. Among the emerging roles for myosins is regulation of the assembly, morphology, and function of actin protrusions such as microvilli. The intestine harbors an elaborate apical membrane composed of highly organized microvilli. Microvilli assembly and function are intricately tied to several myosins including Myosin 1a, non-muscle Myosin 2c, Myosin 5b, Myosin 6, and Myosin 7b. Here, we review the research progress made in our understanding of myosin mediated apical assembly.
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Affiliation(s)
- Melinda A Engevik
- Department of Regenerative Medicine & Cell Biology, Medical University of South Carolina
| | - Amy C Engevik
- Department of Regenerative Medicine & Cell Biology, Medical University of South Carolina.
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6
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Uthaiah CA, Beeraka NM, Rajalakshmi R, Ramya CM, Madhunapantula SV. Role of Neural Stem Cells and Vitamin D Receptor (VDR)-Mediated Cellular Signaling in the Mitigation of Neurological Diseases. Mol Neurobiol 2022; 59:4065-4105. [PMID: 35476289 DOI: 10.1007/s12035-022-02837-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 04/09/2022] [Indexed: 12/19/2022]
Abstract
Specific stem cell-based therapies for treating Alzheimer's disease, Parkinson's disease, and schizophrenia are gaining importance in recent years. Accumulating data is providing further support by demonstrating the efficacy of neural stem cells in enhancing the neurogenesis in the aging brain. In addition to stem cells, recent studies have shown the efficacy of supplementing vitamin D in promoting neurogenesis and neuronal survival. Studies have also demonstrated the presence of mutational variants and single-nucleotide polymorphisms of the vitamin D receptor (VDR) in neurological disorders; however, implications of these mutations in the pathophysiology and response to drug treatment are yet to be explored. Hence, in this article, we have reviewed recent reports pertaining to the role of neural stem cells and VDR-mediated cellular signaling cascades that are involved in enhancing the neurogenesis through Wnt/β-catenin and Sonic Hedgehog pathways. This review benefits neurobiologists and pharmaceutical industry experts to develop stem cell-based and vitamin D-based therapies to better treat the patients suffering from neurological diseases.
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Affiliation(s)
- Chinnappa A Uthaiah
- Center of Excellence in Molecular Biology and Regenerative Medicine (CEMR, DST-FIST Supported Center), Department of Biochemistry (DST-FIST Supported Department), JSS Medical College, JSS Academy of Higher Education & Research (JSS AHER), Mysuru, 570015, Karnataka, India
| | - Narasimha M Beeraka
- Center of Excellence in Molecular Biology and Regenerative Medicine (CEMR, DST-FIST Supported Center), Department of Biochemistry (DST-FIST Supported Department), JSS Medical College, JSS Academy of Higher Education & Research (JSS AHER), Mysuru, 570015, Karnataka, India
| | - R Rajalakshmi
- Department of Physiology, JSS Medical College, JSS Academy of Higher Education & Research (JSS AHER), Mysuru, 570015, Karnataka, India
| | - C M Ramya
- Department of Physiology, JSS Medical College, JSS Academy of Higher Education & Research (JSS AHER), Mysuru, 570015, Karnataka, India
| | - SubbaRao V Madhunapantula
- Center of Excellence in Molecular Biology and Regenerative Medicine (CEMR, DST-FIST Supported Center), Department of Biochemistry (DST-FIST Supported Department), JSS Medical College, JSS Academy of Higher Education & Research (JSS AHER), Mysuru, 570015, Karnataka, India.
- Special Interest Group in Cancer Biology and Cancer Stem Cells (SIG-CBCSC), JSS Academy of Higher Education & Research (JSS AHER), Mysuru, 570015, Karnataka, India.
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7
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Rämö RA, Honkanen J, Nybom I, Gunnarsson JS. Biological Effects of Activated Carbon on Benthic Macroinvertebrates are Determined by Particle Size and Ingestibility of Activated Carbon. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2021; 40:3465-3477. [PMID: 34748656 DOI: 10.1002/etc.5231] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 09/07/2021] [Accepted: 10/14/2021] [Indexed: 06/13/2023]
Abstract
The application of activated carbon (AC) to the surface of contaminated sediments is a promising technology for sediment remediation in situ. Amendment with AC has proved to be effective in reducing bioavailability and sediment-to-water release of hydrophobic organic contaminants. However, AC may cause positive or negative biological responses in benthic organisms. The causes of these effects, which include changes in growth, reproduction, and mortality, are unclear but are thought to be related to the size of AC particles. The present study investigated biological response to AC ranging from ingestible powdered AC to noningestible granular AC in two benthic deposit feeders: the polychaete Marenzelleria spp. and the clam Limecola balthica (syn. Macoma balthica). In the polychaete, exposure to powdered AC (ingestible) reduced both dry weight and carbon assimilation, whereas exposure to granular AC (noningestible) increased both dry weight and carbon assimilation. Responses in the clam were similar but less pronounced, indicating that response levels are species-specific and may vary within a benthic community. In addition, worms exposed to the finest ingestible AC particles had reduced gut microvilli length and reduced gut lumen, indicating starvation. These results strongly suggest that biological responses to AC depend on particle ingestibility, whereby exposure to ingestible particles may cause starvation through reduced bioavailability of food coingested with AC or due to rejection of AC-treated sediment as a food source. Environ Toxicol Chem 2021;40:3465-3477. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
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Affiliation(s)
- Robert A Rämö
- Department of Ecology, Environment, and Plant Sciences, Stockholm University, Stockholm, Sweden
| | - Johanna Honkanen
- Department of Ecology, Environment, and Plant Sciences, Stockholm University, Stockholm, Sweden
| | - Inna Nybom
- Department of Environmental Science, Stockholm University, Stockholm, Sweden
| | - Jonas S Gunnarsson
- Department of Ecology, Environment, and Plant Sciences, Stockholm University, Stockholm, Sweden
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CrvA and CrvB form a curvature-inducing module sufficient to induce cell-shape complexity in Gram-negative bacteria. Nat Microbiol 2021; 6:910-920. [PMID: 34183815 PMCID: PMC8764749 DOI: 10.1038/s41564-021-00924-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 05/21/2021] [Indexed: 01/03/2023]
Abstract
Bacterial species have diverse cell shapes that enable motility, colonization, and virulence. The cell wall defines bacterial shape and is primarily built by two cytoskeleton-guided synthesis machines, the elongasome and the divisome. However, the mechanisms producing complex shapes, like the curved-rod shape of Vibrio cholerae, are incompletely defined. Previous studies have reported that species-specific regulation of cytoskeleton-guided machines enables formation of complex bacterial shapes such as cell curvature and cellular appendages. In contrast, we report that CrvA and CrvB are sufficient to induce complex cell shape autonomously of the cytoskeleton in V. cholerae. The autonomy of the CrvAB module also enables it to induce curvature in the Gram-negative species Escherichia coli, Pseudomonas aeruginosa, Caulobacter crescentus, and Agrobacterium tumefaciens. Using inducible gene expression, quantitative microscopy, and biochemistry we show that CrvA and CrvB circumvent the need for patterning via cytoskeletal elements by regulating each other to form an asymmetrically-localized, periplasmic structure that directly binds to the cell wall. The assembly and disassembly of this periplasmic structure enables dynamic changes in cell shape. Bioinformatics indicate that CrvA and CrvB may have diverged from a single ancestral hybrid protein. Using fusion experiments in V. cholerae, we find that a synthetic CrvA/B hybrid protein is sufficient to induce curvature on its own, but that expression of two distinct proteins, CrvA and CrvB, promotes more rapid curvature induction. We conclude that morphological complexity can arise independently of cell shape specification by the core cytoskeleton-guided synthesis machines.
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A human model of Batten disease shows role of CLN3 in phagocytosis at the photoreceptor-RPE interface. Commun Biol 2021; 4:161. [PMID: 33547385 PMCID: PMC7864947 DOI: 10.1038/s42003-021-01682-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 11/25/2020] [Indexed: 02/07/2023] Open
Abstract
Mutations in CLN3 lead to photoreceptor cell loss in CLN3 disease, a lysosomal storage disorder characterized by childhood-onset vision loss, neurological impairment, and premature death. However, how CLN3 mutations cause photoreceptor cell death is not known. Here, we show that CLN3 is required for phagocytosis of photoreceptor outer segment (POS) by retinal pigment epithelium (RPE) cells, a cellular process essential for photoreceptor survival. Specifically, a proportion of CLN3 in human, mouse, and iPSC-RPE cells localized to RPE microvilli, the site of POS phagocytosis. Furthermore, patient-derived CLN3 disease iPSC-RPE cells showed decreased RPE microvilli density and reduced POS binding and ingestion. Notably, POS phagocytosis defect in CLN3 disease iPSC-RPE cells could be rescued by wild-type CLN3 gene supplementation. Altogether, these results illustrate a novel role of CLN3 in regulating POS phagocytosis and suggest a contribution of primary RPE dysfunction for photoreceptor cell loss in CLN3 disease that can be targeted by gene therapy.
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Mucin-2 knockout is a model of intercellular junction defects, mitochondrial damage and ATP depletion in the intestinal epithelium. Sci Rep 2020; 10:21135. [PMID: 33273633 PMCID: PMC7713437 DOI: 10.1038/s41598-020-78141-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 11/18/2020] [Indexed: 12/11/2022] Open
Abstract
The disruption of the protective intestinal barrier—the ‘leaky gut’—is a common complication of the inflammatory bowel disease. There is limited data on the mechanisms of the intestinal barrier disruption upon low-grade inflammation characteristic of patients with inflammatory bowel disease in clinical remission. Thus, animal models that recapitulate the complexity of chronic intestinal inflammation in vivo are of particular interest. In this study, we used Mucin-2 (Muc2) knockout mice predisposed to colitis to study intestinal barrier upon chronic inflammation. We used 4-kDa FITC-Dextran assay and transmission electron microscopy to demonstrate the increased intestinal permeability and morphological defects in intercellular junctions in Muc2 knockout mice. Confocal microscopy revealed the disruption of the apical F-actin cytoskeleton and delocalization of tight junction protein Claudin-3 from the membrane. We further demonstrate mitochondrial damage, impaired oxygen consumption and the reduction of the intestinal ATP content in Muc2 knockout mice. Finally, we show that chemically induced mitochondrial uncoupling in the wild type mice mimics the intestinal barrier disruption in vivo and causes partial loss of F-actin and membrane localization of Claudin-3. We propose that mitochondrial damage and metabolic shifts during chronic inflammation contribute to the leaky gut syndrome in Muc2 knockout animal model of colitis.
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Mi R, Rabbi MH, Sun Y, Li X, Ma S, Wen Z, Meng N, Li Y, Du X, Li S. Enhanced protein phosphorylation in Apostichopus japonicus intestine triggered by tussah immunoreactive substances might be involved in the regulation of immune-related signaling pathways. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2020; 37:100757. [PMID: 33197859 DOI: 10.1016/j.cbd.2020.100757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 10/25/2020] [Accepted: 10/29/2020] [Indexed: 11/28/2022]
Abstract
The sea cucumber Apostichopus japonicus is an economically important species owing to its high nutritive and medicinal value. In order to avoid the pollution resulting from the overuse of antibiotics in A. japonicus aquaculture, various immunostimulants have been used as an alternative to improve the efficiency of A. japonicus farming. Our previous proteomic investigation has shown that several proteins participating in the immune-related physiology of A. japonicus were differentially expressed in the intestinal tissue in response to tussah immunoreactive substances (TIS). This study further explored the immunostimulation mechanism of TIS in A. japonicus. Phosphoproteomics technology was used to investigate the effect of TIS on protein phosphorylation in the intestine of A. japonicus following feeding with a TIS-supplemented diet. A total of 213 unique phosphoproteins were detected from 225 unique phosphopeptides. KEGG pathway analysis showed that majority of the phosphoproteins are involved in endocytosis, carbon metabolism and spliceosome functional group. Sixteen of the phosphoproteins exhibited differential phosphorylation in response to TIS and 12 of these were found to associate with biological functions. Of these 12 phosphoproteins, eight exhibited enhanced phosphorylation while four displayed reduced phosphorylation. These 12 proteins were further analyzed and all were found to play a role in regulating some aspects of the immune system and the growth of sea cucumbers, especially in phagocytosis, energy metabolism and disease resistance. The findings of this study could therefore shed new light on the immune pathways of sea cucumber that are affected by TIS. This could help us to better understand the underlying mechanism linked to the immunoenhancement of A. japonicus in response to TIS, one that is associated with the change in protein phosphorylation.
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Affiliation(s)
- Rui Mi
- Liaoning Ocean and Fisheries Science Research Institute, Liaoning Academy of Agricultural Sciences, Dalian 116024, PR China
| | - Md Hasim Rabbi
- College of Fisheries and Life Science, Dalian Ocean University, Dalian 116024, PR China
| | - Yongxin Sun
- Liaoning Ocean and Fisheries Science Research Institute, Liaoning Academy of Agricultural Sciences, Dalian 116024, PR China.
| | - Xuejun Li
- Liaoning Ocean and Fisheries Science Research Institute, Liaoning Academy of Agricultural Sciences, Dalian 116024, PR China
| | - Shuhui Ma
- Liaoning Ocean and Fisheries Science Research Institute, Liaoning Academy of Agricultural Sciences, Dalian 116024, PR China
| | - Zhixin Wen
- Liaoning Ocean and Fisheries Science Research Institute, Liaoning Academy of Agricultural Sciences, Dalian 116024, PR China
| | - Nan Meng
- Liaoning Ocean and Fisheries Science Research Institute, Liaoning Academy of Agricultural Sciences, Dalian 116024, PR China
| | - Yajie Li
- Liaoning Ocean and Fisheries Science Research Institute, Liaoning Academy of Agricultural Sciences, Dalian 116024, PR China
| | - Xingfan Du
- Liaoning Ocean and Fisheries Science Research Institute, Liaoning Academy of Agricultural Sciences, Dalian 116024, PR China
| | - Shuying Li
- Liaoning Ocean and Fisheries Science Research Institute, Liaoning Academy of Agricultural Sciences, Dalian 116024, PR China
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12
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Mandal M, Ghosh B, Rajput M, Chatterjee J. Impact of intercellular connectivity on epithelial mesenchymal transition plasticity. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118784. [DOI: 10.1016/j.bbamcr.2020.118784] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 06/14/2020] [Accepted: 06/18/2020] [Indexed: 12/14/2022]
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13
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Sharma S, Kumaran GK, Hanukoglu I. High-resolution imaging of the actin cytoskeleton and epithelial sodium channel, CFTR, and aquaporin-9 localization in the vas deferens. Mol Reprod Dev 2020; 87:305-319. [PMID: 31950584 DOI: 10.1002/mrd.23317] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 01/05/2020] [Indexed: 12/30/2022]
Abstract
Vas deferens is a conduit for sperm and fluid from the epididymis to the urethra. The duct is surrounded by a thick smooth muscle layer. To map the actin cytoskeleton of the duct and its epithelium, we reacted sections of the proximal and distal regions with fluorescent phalloidin. Confocal microscopic imaging showed that the cylinder-shaped epithelium of the proximal region has a thick apical border of actin filaments that form microvilli. The epithelium of the distal region is covered with tall stereocilia (13-18 µm) that extend from the apical border into the lumen. In both regions, the lateral and basal cell borders showed a thin lining of actin cytoskeleton. The vas deferens epithelium contains various channels to regulate the fluid composition in the lumen. We mapped the localization of the epithelial sodium channel (ENaC), aquaporin-9 (AQP9), and cystic fibrosis transmembrane conductance regulator (CFTR) in the rat and mouse vas deferens. ENaC and AQP9 immunofluorescence were localized on the luminal surface and stereocilia and also in the basal and smooth muscle layers. CFTR immunofluorescence appeared only on the luminal surface and in smooth muscle layers. The localization of all three channels on the apical surface of the columnar epithelial cells provides clear evidence that these channels are involved concurrently in the regulation of fluid and electrolyte balance in the lumen of the vas deferens. ENaC allows the flow of Na+ ions from the lumen into the cytoplasm, and the osmotic gradient generated provides the driving force for the passive flow of water through AQP channels.
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Affiliation(s)
- Sachin Sharma
- Laboratory of Cell Biology, Ariel University, Ariel, Israel
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14
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Kumaran GK, Hanukoglu I. Identification and classification of epithelial cells in nephron segments by actin cytoskeleton patterns. FEBS J 2019; 287:1176-1194. [PMID: 31605441 PMCID: PMC7384063 DOI: 10.1111/febs.15088] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 09/11/2019] [Accepted: 10/09/2019] [Indexed: 12/11/2022]
Abstract
The basic functional unit in a kidney is the nephron, which is a long and morphologically segmented tubule. The nephron begins with a cluster of capillaries called glomerulus through which the blood is filtered into the Bowman's space. The filtrate flows through the nephron segments. During this flow, electrolytes and solutes are reabsorbed by channels and transport systems into the capillaries wrapped around the nephron. Many questions related to renal function focus on identifying the sites of expression of these systems. In this study, we mapped whole kidney sections by confocal microscopic imaging of fluorescent phalloidin, which binds to actin filaments. In tile scans (composed of hundreds of images) of these sections, the cortex and the medullary regions (outer and inner stripes of the outer medulla, and inner medulla) could be easily identified by their cytoskeletal patterns. At a higher resolution, we identified distinct features of the actin cytoskeleton in the apical, basal, and lateral borders of the cells. These features could be used to identify segments of a nephron (the proximal tubule, thin and thick segments of Henle's loop, and distal tubule), the collecting duct system, the papillary ducts in the papilla, and the urothelium that covers the pelvis. To verify our findings, we used additional markers, including aquaporin isoforms, cytokeratin 8‐18, and WGA lectin. This study highlights the power of high‐resolution confocal microscopy for identifying specific cell types using the simple probe of F‐actin‐binding phalloidin.
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15
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Markovic MA, Brubaker PL. The roles of glucagon-like peptide-2 and the intestinal epithelial insulin-like growth factor-1 receptor in regulating microvillus length. Sci Rep 2019; 9:13010. [PMID: 31506583 PMCID: PMC6737075 DOI: 10.1038/s41598-019-49510-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 08/27/2019] [Indexed: 12/25/2022] Open
Abstract
Microvilli are tiny projections on the apical end of enterocytes, aiding in the digestion and absorption of nutrients. One of their key features is uniform length, but how this is regulated is poorly understood. Glucagon-like peptide-2 (GLP-2) has been shown to increase microvillus length but, the requirement of its downstream mediator, the intestinal epithelial insulin-like growth factor-1 receptor (IE-IGF-1R), and the microvillus proteins acted upon by GLP-2, remain unknown. Using IE-IGF-1R knockout (KO) mice, treated with either long-acting human (h) (GLY2)GLP-2 or vehicle for 11d, it was found that the h(GLY2)GLP-2-induced increase in microvillus length required the IE-IGF-1R. Furthermore, IE-IGF-1R KO alone resulted in a significant decrease in microvillus length. Examination of the brush border membrane proteome as well as of whole jejunal mucosa demonstrated that villin was increased with h(GLY2)GLP-2 treatment in an IE-IGF-1R-dependent manner. Under both basal conditions and with h(GLY2)GLP-2 treatment of the IE-IGF-1R KO mice, changes in villin, IRTKS-1, harmonin, β-actin, and myosin-1a did not explain the decrease in microvillus length, in either the brush border or jejunal mucosa of KO animals. Collectively, these studies define a new role for the IE-IGF-1R within the microvillus, in both the signaling cascade induced by GLP-2, as well as endogenously.
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Affiliation(s)
- Melanie A Markovic
- Department of Physiology Rm 3366 Medical Sciences Building, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Patricia L Brubaker
- Department of Physiology Rm 3366 Medical Sciences Building, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada. .,Department of Medicine Rm 3366 Medical Sciences Building, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
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16
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Huang W, Isoherranen N. Development of a Dynamic Physiologically Based Mechanistic Kidney Model to Predict Renal Clearance. CPT-PHARMACOMETRICS & SYSTEMS PHARMACOLOGY 2018; 7:593-602. [PMID: 30043446 PMCID: PMC6157663 DOI: 10.1002/psp4.12321] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 05/31/2018] [Indexed: 11/10/2022]
Abstract
Renal clearance is usually predicted via empirical approaches including quantitative structure activity relationship and allometric scaling. Recently, mechanistic prediction approaches using in silico kidney models have been proposed. However, empirical scaling factors are typically used to adjust for either passive diffusion or active secretion, to acceptably predict renal clearances. The goal of this study was to establish a renal clearance simulation tool that allows prediction of renal clearance (filtration and pH-dependent passive reabsorption) from in vitro permeability data. A 35-compartment physiologically based mechanistic kidney model was developed based on human physiology. The model was verified using 46 test compounds, including neutrals, acids, bases, and zwitterions. The feasibility of incorporating active secretion and pH-dependent bidirectional passive diffusion into the model was demonstrated using para-aminohippuric acid (PAH), cimetidine, memantine, and salicylic acid. The developed model enables simulation of renal clearance from in vitro permeability data, with predicted renal clearance within twofold of observed for 87% of the test drugs.
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Affiliation(s)
- Weize Huang
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, Washington, USA
| | - Nina Isoherranen
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, Washington, USA
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17
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Inflammation induced ER stress affects absorptive intestinal epithelial cells function and integrity. Int Immunopharmacol 2018; 55:336-344. [DOI: 10.1016/j.intimp.2017.12.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Revised: 12/11/2017] [Accepted: 12/12/2017] [Indexed: 02/07/2023]
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18
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Franz J, Grünebaum J, Schäfer M, Mulac D, Rehfeldt F, Langer K, Kramer A, Riethmüller C. Rhombic organization of microvilli domains found in a cell model of the human intestine. PLoS One 2018; 13:e0189970. [PMID: 29320535 PMCID: PMC5761853 DOI: 10.1371/journal.pone.0189970] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 12/05/2017] [Indexed: 01/22/2023] Open
Abstract
Symmetry is rarely found on cellular surfaces. An exception is the brush border of microvilli, which are essential for the proper function of transport epithelia. In a healthy intestine, they appear densely packed as a 2D-hexagonal lattice. For in vitro testing of intestinal transport the cell line Caco-2 has been established. As reported by electron microscopy, their microvilli arrange primarily in clusters developing secondly into a 2D-hexagonal lattice. Here, atomic force microscopy (AFM) was employed under aqueous buffer conditions on Caco-2 cells, which were cultivated on permeable filter membranes for optimum differentiation. For analysis, the exact position of each microvillus was detected by computer vision; subsequent Fourier transformation yielded the type of 2D-lattice. It was confirmed, that Caco-2 cells can build a hexagonal lattice of microvilli and form clusters. Moreover, a second type of arrangement was discovered, namely a rhombic lattice, which appeared at sub-maximal densities of microvilli with (29 ± 4) microvilli / μm2. Altogether, the findings indicate the existence of a yet undescribed pattern in cellular organization.
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Affiliation(s)
- Jonas Franz
- Faculty of Physics, Georg-August-Universität, Göttingen, Germany
- Max Planck Institute for Dynamics and Self-Organization, Theoretical Neurophysics, Göttingen, Germany
| | - Jonas Grünebaum
- Institute for Pharmaceutical Technology and Biopharmacy, University of Münster, Münster, Germany
| | - Marcus Schäfer
- nanoAnalytics GmbH, Centre for Nanotechnology, Münster, Germany
| | - Dennis Mulac
- Institute for Pharmaceutical Technology and Biopharmacy, University of Münster, Münster, Germany
| | - Florian Rehfeldt
- Third Institute of Physics—Biophysics, Georg-August-Universität, Göttingen, Germany
| | - Klaus Langer
- Institute for Pharmaceutical Technology and Biopharmacy, University of Münster, Münster, Germany
| | - Armin Kramer
- Serend-ip GmbH, Centre for Nanotechnology, Münster, Germany
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19
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Abstract
The actin cytoskeleton-a collection of actin filaments with their accessory and regulatory proteins-is the primary force-generating machinery in the cell. It can produce pushing (protrusive) forces through coordinated polymerization of multiple actin filaments or pulling (contractile) forces through sliding actin filaments along bipolar filaments of myosin II. Both force types are particularly important for whole-cell migration, but they also define and change the cell shape and mechanical properties of the cell surface, drive the intracellular motility and morphogenesis of membrane organelles, and allow cells to form adhesions with each other and with the extracellular matrix.
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Affiliation(s)
- Tatyana Svitkina
- Department of Biology, University of Pennsylvania, 221 Leidy Labs, Philadelphia, Pennsylvania 19104
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20
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Curto VF, Marchiori B, Hama A, Pappa AM, Ferro MP, Braendlein M, Rivnay J, Fiocchi M, Malliaras GG, Ramuz M, Owens RM. Organic transistor platform with integrated microfluidics for in-line multi-parametric in vitro cell monitoring. MICROSYSTEMS & NANOENGINEERING 2017; 3:17028. [PMID: 31057869 PMCID: PMC6445009 DOI: 10.1038/micronano.2017.28] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 03/31/2017] [Accepted: 04/10/2017] [Indexed: 05/02/2023]
Abstract
Future drug discovery and toxicology testing could benefit significantly from more predictive and multi-parametric readouts from in vitro models. Despite the recent advances in the field of microfluidics, and more recently organ-on-a-chip technology, there is still a high demand for real-time monitoring systems that can be readily embedded with microfluidics. In addition, multi-parametric monitoring is essential to improve the predictive quality of the data used to inform clinical studies that follow. Here we present a microfluidic platform integrated with in-line electronic sensors based on the organic electrochemical transistor. Our goals are two-fold, first to generate a platform to host cells in a more physiologically relevant environment (using physiologically relevant fluid shear stress (FSS)) and second to show efficient integration of multiple different methods for assessing cell morphology, differentiation, and integrity. These include optical imaging, impedance monitoring, metabolite sensing, and a wound-healing assay. We illustrate the versatility of this multi-parametric monitoring in giving us increased confidence to validate the improved differentiation of cells toward a physiological profile under FSS, thus yielding more accurate data when used to assess the effect of drugs or toxins. Overall, this platform will enable high-content screening for in vitro drug discovery and toxicology testing and bridges the existing gap in the integration of in-line sensors in microfluidic devices.
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Affiliation(s)
- Vincenzo F. Curto
- Department of Bioelectronics, Ecole Nationale Supérieure des Mines, CMP-EMSE, MOC, 880 Avenue de Mimet, Gardanne 13541, France
| | - Bastien Marchiori
- Department of Bioelectronics, Ecole Nationale Supérieure des Mines, CMP-EMSE, MOC, 880 Avenue de Mimet, Gardanne 13541, France
- Flexible Electronics Department, Ecole Nationale Supérieure des Mines CMP-EMSE, MOC, 880 Avenue de Mimet, Gardanne 13541, France
| | - Adel Hama
- Department of Bioelectronics, Ecole Nationale Supérieure des Mines, CMP-EMSE, MOC, 880 Avenue de Mimet, Gardanne 13541, France
| | - Anna-Maria Pappa
- Department of Bioelectronics, Ecole Nationale Supérieure des Mines, CMP-EMSE, MOC, 880 Avenue de Mimet, Gardanne 13541, France
| | - Magali P. Ferro
- Department of Bioelectronics, Ecole Nationale Supérieure des Mines, CMP-EMSE, MOC, 880 Avenue de Mimet, Gardanne 13541, France
| | - Marcel Braendlein
- Department of Bioelectronics, Ecole Nationale Supérieure des Mines, CMP-EMSE, MOC, 880 Avenue de Mimet, Gardanne 13541, France
| | - Jonathan Rivnay
- Department of Bioelectronics, Ecole Nationale Supérieure des Mines, CMP-EMSE, MOC, 880 Avenue de Mimet, Gardanne 13541, France
| | - Michel Fiocchi
- Department of Bioelectronics, Ecole Nationale Supérieure des Mines, CMP-EMSE, MOC, 880 Avenue de Mimet, Gardanne 13541, France
| | - George G. Malliaras
- Department of Bioelectronics, Ecole Nationale Supérieure des Mines, CMP-EMSE, MOC, 880 Avenue de Mimet, Gardanne 13541, France
| | - Marc Ramuz
- Flexible Electronics Department, Ecole Nationale Supérieure des Mines CMP-EMSE, MOC, 880 Avenue de Mimet, Gardanne 13541, France
| | - Róisín M. Owens
- Department of Bioelectronics, Ecole Nationale Supérieure des Mines, CMP-EMSE, MOC, 880 Avenue de Mimet, Gardanne 13541, France
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21
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Sato O, Komatsu S, Sakai T, Tsukasaki Y, Tanaka R, Mizutani T, Watanabe TM, Ikebe R, Ikebe M. Human myosin VIIa is a very slow processive motor protein on various cellular actin structures. J Biol Chem 2017; 292:10950-10960. [PMID: 28507101 DOI: 10.1074/jbc.m116.765966] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 05/11/2017] [Indexed: 11/06/2022] Open
Abstract
Human myosin VIIa (MYO7A) is an actin-linked motor protein associated with human Usher syndrome (USH) type 1B, which causes human congenital hearing and visual loss. Although it has been thought that the role of human myosin VIIa is critical for USH1 protein tethering with actin and transportation along actin bundles in inner-ear hair cells, myosin VIIa's motor function remains unclear. Here, we studied the motor function of the tail-truncated human myosin VIIa dimer (HM7AΔTail/LZ) at the single-molecule level. We found that the HM7AΔTail/LZ moves processively on single actin filaments with a step size of 35 nm. Dwell-time distribution analysis indicated an average waiting time of 3.4 s, yielding ∼0.3 s-1 for the mechanical turnover rate; hence, the velocity of HM7AΔTail/LZ was extremely slow, at 11 nm·s-1 We also examined HM7AΔTail/LZ movement on various actin structures in demembranated cells. HM7AΔTail/LZ showed unidirectional movement on actin structures at cell edges, such as lamellipodia and filopodia. However, HM7AΔTail/LZ frequently missed steps on actin tracks and exhibited bidirectional movement at stress fibers, which was not observed with tail-truncated myosin Va. These results suggest that the movement of the human myosin VIIa motor protein is more efficient on lamellipodial and filopodial actin tracks than on stress fibers, which are composed of actin filaments with different polarity, and that the actin structures influence the characteristics of cargo transportation by human myosin VIIa. In conclusion, myosin VIIa movement appears to be suitable for translocating USH1 proteins on stereocilia actin bundles in inner-ear hair cells.
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Affiliation(s)
- Osamu Sato
- From the Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas 75708
| | - Satoshi Komatsu
- From the Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas 75708
| | - Tsuyoshi Sakai
- From the Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas 75708
| | - Yoshikazu Tsukasaki
- From the Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas 75708.,Department of Pharmacology, University of Illinois College of Medicine, Chicago, Illinois 60612
| | - Ryosuke Tanaka
- Graduate School of Information Science and Technology, Hokkaido University, Sapporo 060-0814, Japan
| | - Takeomi Mizutani
- Department of Advanced Transdisciplinary Sciences, Faculty of Advanced Life Science, Hokkaido University, Sapporo 060-0810, Japan, and
| | - Tomonobu M Watanabe
- Laboratory for Comprehensive Bioimaging, RIKEN Quantitative Biology Center, Suita, Osaka 565-0874, Japan
| | - Reiko Ikebe
- From the Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas 75708
| | - Mitsuo Ikebe
- From the Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas 75708,
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22
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Cakebread JA, Callaghan M, Broadhurst M, Harris P, Wheeler TT. Free secretory component from bovine milk aggregates enteropathogenic Escherichia coli and inhibits binding to intestinal cells. Int Dairy J 2017. [DOI: 10.1016/j.idairyj.2016.12.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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23
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Kang CK, Lin CS, Hu YC, Tsai SC, Lee TH. The expression of VILL protein is hypoosmotic-dependent in the lamellar gill ionocytes of Otocephala teleost fish, Chanos chanos. Comp Biochem Physiol A Mol Integr Physiol 2017; 203:59-68. [DOI: 10.1016/j.cbpa.2016.08.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 05/13/2016] [Accepted: 08/16/2016] [Indexed: 02/09/2023]
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24
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Fong‐ngern K, Vinaiphat A, Thongboonkerd V. Microvillar injury in renal tubular epithelial cells induced by calcium oxalate crystal and the protective role of epigallocatechin‐3‐gallate. FASEB J 2016; 31:120-131. [DOI: 10.1096/fj.201600543r] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 09/16/2016] [Indexed: 02/05/2023]
Affiliation(s)
- Kedsarin Fong‐ngern
- Medical Proteomics Unit, Office for Research and DevelopmentFaculty of Medicine, Siriraj Hospital Bangkok Thailand
- Center for Research in Complex Systems ScienceMahidol University Bangkok Thailand
| | - Arada Vinaiphat
- Medical Proteomics Unit, Office for Research and DevelopmentFaculty of Medicine, Siriraj Hospital Bangkok Thailand
- Center for Research in Complex Systems ScienceMahidol University Bangkok Thailand
| | - Visith Thongboonkerd
- Medical Proteomics Unit, Office for Research and DevelopmentFaculty of Medicine, Siriraj Hospital Bangkok Thailand
- Center for Research in Complex Systems ScienceMahidol University Bangkok Thailand
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25
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Xu X, Wang X, Todd EM, Jaeger ER, Vella JL, Mooren OL, Feng Y, Hu J, Cooper JA, Morley SC, Huang YH. Mst1 Kinase Regulates the Actin-Bundling Protein L-Plastin To Promote T Cell Migration. THE JOURNAL OF IMMUNOLOGY 2016; 197:1683-91. [PMID: 27465533 DOI: 10.4049/jimmunol.1600874] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 06/27/2016] [Indexed: 12/31/2022]
Abstract
Exploring the mechanisms controlling lymphocyte trafficking is essential for understanding the function of the immune system and the pathophysiology of immunodeficiencies. The mammalian Ste20-like kinase 1 (Mst1) has been identified as a critical signaling mediator of T cell migration, and loss of Mst1 results in immunodeficiency disease. Although Mst1 is known to support T cell migration through induction of cell polarization and lamellipodial formation, the downstream effectors of Mst1 are incompletely defined. Mice deficient for the actin-bundling protein L-plastin (LPL) have phenotypes similar to mice lacking Mst1, including decreased T cell polarization, lamellipodial formation, and cell migration. We therefore asked whether LPL functions downstream of Mst1. The regulatory N-terminal domain of LPL contains a consensus Mst1 phosphorylation site at Thr(89) We found that Mst1 can phosphorylate LPL in vitro and that Mst1 can interact with LPL in cells. Removal of the Mst1 phosphorylation site by mutating Thr(89) to Ala impaired localization of LPL to the actin-rich lamellipodia of T cells. Expression of the T89A LPL mutant failed to restore migration of LPL-deficient T cells in vitro. Furthermore, expression of T89A LPL in LPL-deficient hematopoietic cells, using bone marrow chimeras, failed to rescue the phenotype of decreased thymic egress. These results identify LPL as a key effector of Mst1 and establish a novel mechanism linking a signaling intermediate to an actin-binding protein critical to T cell migration.
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Affiliation(s)
- Xiaolu Xu
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110
| | - Xinxin Wang
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110
| | - Elizabeth M Todd
- Division of Infectious Diseases, Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110
| | - Emily R Jaeger
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110
| | - Jennifer L Vella
- Department of Microbiology and Immunology, The Geisel School of Medicine at Dartmouth, Lebanon, NH 03756
| | - Olivia L Mooren
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110; Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110; and
| | - Yunfeng Feng
- Department of Pathology, The Geisel School of Medicine at Dartmouth, Lebanon, NH 03756
| | - Jiancheng Hu
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110
| | - John A Cooper
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110; Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110; and
| | - Sharon Celeste Morley
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110; Division of Infectious Diseases, Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110;
| | - Yina H Huang
- Department of Microbiology and Immunology, The Geisel School of Medicine at Dartmouth, Lebanon, NH 03756; Department of Pathology, The Geisel School of Medicine at Dartmouth, Lebanon, NH 03756
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26
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Peña JF, Alié A, Richter DJ, Wang L, Funayama N, Nichols SA. Conserved expression of vertebrate microvillar gene homologs in choanocytes of freshwater sponges. EvoDevo 2016; 7:13. [PMID: 27413529 PMCID: PMC4942974 DOI: 10.1186/s13227-016-0050-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Accepted: 06/28/2016] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND The microvillus is a versatile organelle that serves important functions in disparate animal cell types. However, from a molecular perspective, the microvillus has been well studied in only a few, predominantly vertebrate, contexts. Little is known about how differences in microvillar structure contribute to differences in function, and how these differences evolved. We sequenced the transcriptome of the freshwater sponge, Ephydatia muelleri, and examined the expression of vertebrate microvillar gene homologs in choanocytes-the only microvilli-bearing cell type present in sponges. Sponges offer a distant phylogenetic comparison with vertebrates, and choanocytes are central to discussions about early animal evolution due to their similarity with choanoflagellates, the single-celled sister lineage of modern animals. RESULTS We found that, from a genomic perspective, sponges have conserved homologs of most vertebrate microvillar genes, most of which are expressed in choanocytes, and many of which exhibit choanocyte-specific or choanocyte-enriched expression. Possible exceptions include the cadherins that form intermicrovillar links in the enterocyte brush border and hair cell stereocilia of vertebrates and cnidarians. No obvious orthologs of these proteins were detected in sponges, but at least four candidate cadherins were identified as choanocyte-enriched and might serve this function. In contrast to the evidence for conserved microvillar structure in sponges and vertebrates, we found that choanoflagellates and ctenophores lack homologs of many fundamental microvillar genes, suggesting that microvillar structure may diverge significantly in these lineages, warranting further study. CONCLUSIONS The available evidence suggests that microvilli evolved early in the prehistory of modern animals and have been repurposed to serve myriad functions in different cellular contexts. Detailed understanding of the sequence by which different microvilli-bearing cell/tissue types diversified will require further study of microvillar composition and development in disparate cell types and lineages. Of particular interest are the microvilli of choanoflagellates, ctenophores, and sponges, which collectively bracket the earliest events in animal evolution.
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Affiliation(s)
- Jesús F. Peña
- />Department of Biological Sciences, University of Denver, F.W. Olin Hall, Room 102, 2190 E. Iliff Ave., Denver, CO 80208 USA
| | - Alexandre Alié
- />Laboratoire de Biologie du Développement de Villefranche-sur-mer, CNRS, Sorbonne Universités, UPMC Univ Paris 06, Observatoire Océanographique, 06230 Villefranche-sur-mer, France
- />Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, 606-8502 Japan
| | - Daniel J. Richter
- />Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3200 USA
- />UMR 7144, CNRS and Sorbonne Universités Université Pierre et Marie Curie (UPMC) Paris 06, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France
| | - Lingyu Wang
- />Department of Biology, University of Miami, 208 Cox Science Center, 1301 Memorial Drive, Coral Gables, FL 33124 USA
| | - Noriko Funayama
- />Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, 606-8502 Japan
| | - Scott A. Nichols
- />Department of Biological Sciences, University of Denver, F.W. Olin Hall, Room 102, 2190 E. Iliff Ave., Denver, CO 80208 USA
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Courjaret R, Hodeify R, Hubrack S, Ibrahim A, Dib M, Daas S, Machaca K. The Ca2+-activated Cl- channel Ano1 controls microvilli length and membrane surface area in the oocyte. J Cell Sci 2016; 129:2548-58. [PMID: 27173493 DOI: 10.1242/jcs.188367] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 05/02/2016] [Indexed: 12/12/2022] Open
Abstract
Ca(2+)-activated Cl(-) channels (CaCCs) play important physiological functions in epithelia and other tissues. In frog oocytes the CaCC Ano1 regulates resting membrane potential and the block to polyspermy. Here, we show that Ano1 expression increases the oocyte surface, revealing a novel function for Ano1 in regulating cell morphology. Confocal imaging shows that Ano1 increases microvilli length, which requires ERM-protein-dependent linkage to the cytoskeleton. A dominant-negative form of the ERM protein moesin precludes the Ano1-dependent increase in membrane area. Furthermore, both full-length and the truncated dominant-negative forms of moesin co-localize with Ano1 to the microvilli, and the two proteins co-immunoprecipitate. The Ano1-moesin interaction limits Ano1 lateral membrane mobility and contributes to microvilli scaffolding, therefore stabilizing larger membrane structures. Collectively, these results reveal a newly identified role for Ano1 in shaping the plasma membrane during oogenesis, with broad implications for the regulation of microvilli in epithelia.
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Affiliation(s)
- Raphael Courjaret
- Department of Physiology and Biophysics, Weill Cornell Medical College in Qatar, Education City - Qatar Foundation, Luqta Street, PO Box 24144, Doha 24144, Qatar
| | - Rawad Hodeify
- Department of Physiology and Biophysics, Weill Cornell Medical College in Qatar, Education City - Qatar Foundation, Luqta Street, PO Box 24144, Doha 24144, Qatar
| | - Satanay Hubrack
- Department of Physiology and Biophysics, Weill Cornell Medical College in Qatar, Education City - Qatar Foundation, Luqta Street, PO Box 24144, Doha 24144, Qatar
| | - Awab Ibrahim
- Department of Physiology and Biophysics, Weill Cornell Medical College in Qatar, Education City - Qatar Foundation, Luqta Street, PO Box 24144, Doha 24144, Qatar
| | - Maya Dib
- Department of Physiology and Biophysics, Weill Cornell Medical College in Qatar, Education City - Qatar Foundation, Luqta Street, PO Box 24144, Doha 24144, Qatar
| | - Sahar Daas
- Department of Physiology and Biophysics, Weill Cornell Medical College in Qatar, Education City - Qatar Foundation, Luqta Street, PO Box 24144, Doha 24144, Qatar
| | - Khaled Machaca
- Department of Physiology and Biophysics, Weill Cornell Medical College in Qatar, Education City - Qatar Foundation, Luqta Street, PO Box 24144, Doha 24144, Qatar
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Nossol C, Barta-Böszörményi A, Kahlert S, Zuschratter W, Faber-Zuschratter H, Reinhardt N, Ponsuksili S, Wimmers K, Diesing AK, Rothkötter HJ. Comparing Two Intestinal Porcine Epithelial Cell Lines (IPECs): Morphological Differentiation, Function and Metabolism. PLoS One 2015; 10:e0132323. [PMID: 26147118 PMCID: PMC4493080 DOI: 10.1371/journal.pone.0132323] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 06/12/2015] [Indexed: 11/23/2022] Open
Abstract
The pig shows genetical and physiological resemblance to human, which predestines it as an experimental animal model especially for mucosal physiology. Therefore, the intestinal epithelial cell lines 1 and J2 (IPEC-1, IPEC-J2) - spontaneously immortalised cell lines from the porcine intestine - are important tools for studying intestinal function. A microarray (GeneChip Porcine Genome Array) was performed to compare the genome wide gene expression of IPECs. Different significantly up-regulated pathways were identified, like “lysosome”, “pathways in cancer”, “regulation of actin cytoskeleton” and “oxidative phosphorylation” in IPEC-J2 in comparison to IPEC-1. On the other hand, “spliceosome”, “ribosome”, “RNA-degradation” and “tight junction” are significantly down-regulated pathways in IPEC-J2 in comparison to IPEC-1. Examined pathways were followed up by functional analyses. ATP-, oxygen, glucose and lactate-measurement provide evidence for up-regulation of oxidative phosphorylation in IPEC-J2. These cells seem to be more active in their metabolism than IPEC-1 cells due to a significant higher ATP-content as well as a higher O2- and glucose-consumption. The down-regulated pathway “ribosome” was followed up by measurement of RNA- and protein content. In summary, IPEC-J2 is a morphologically and functionally more differentiated cell line in comparison to IPEC-1. In addition, IPEC-J2 cells are a preferential tool for in vitro studies with the focus on metabolism.
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Affiliation(s)
- Constanze Nossol
- Institute of Anatomy, Otto-von-Guericke University Magdeburg, 39120, Magdeburg, Germany
- * E-mail:
| | | | - Stefan Kahlert
- Institute of Anatomy, Otto-von-Guericke University Magdeburg, 39120, Magdeburg, Germany
| | | | | | - Nicole Reinhardt
- Institute of Anatomy, Otto-von-Guericke University Magdeburg, 39120, Magdeburg, Germany
| | - Siriluk Ponsuksili
- Leibniz Institute of Farm Animal Biology (FBN) Dummerstorf, 18196, Dummerstorf, Germany
| | - Klaus Wimmers
- Leibniz Institute of Farm Animal Biology (FBN) Dummerstorf, 18196, Dummerstorf, Germany
| | - Anne-Kathrin Diesing
- Institute of Anatomy, Otto-von-Guericke University Magdeburg, 39120, Magdeburg, Germany
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Brown JW, Bullitt E, Sriswasdi S, Harper S, Speicher DW, McKnight CJ. The Physiological Molecular Shape of Spectrin: A Compact Supercoil Resembling a Chinese Finger Trap. PLoS Comput Biol 2015; 11:e1004302. [PMID: 26067675 PMCID: PMC4466138 DOI: 10.1371/journal.pcbi.1004302] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 04/27/2015] [Indexed: 01/29/2023] Open
Abstract
The primary, secondary, and tertiary structures of spectrin are reasonably well defined, but the structural basis for the known dramatic molecular shape change, whereby the molecular length can increase three-fold, is not understood. In this study, we combine previously reported biochemical and high-resolution crystallographic data with structural mass spectroscopy and electron microscopic data to derive a detailed, experimentally-supported quaternary structure of the spectrin heterotetramer. In addition to explaining spectrin’s physiological resting length of ~55-65 nm, our model provides a mechanism by which spectrin is able to undergo a seamless three-fold extension while remaining a linear filament, an experimentally observed property. According to the proposed model, spectrin’s quaternary structure and mechanism of extension is similar to a Chinese Finger Trap: at shorter molecular lengths spectrin is a hollow cylinder that extends by increasing the pitch of each spectrin repeat, which decreases the internal diameter. We validated our model with electron microscopy, which demonstrated that, as predicted, spectrin is hollow at its biological resting length of ~55-65 nm. The model is further supported by zero-length chemical crosslink data indicative of an approximately 90 degree bend between adjacent spectrin repeats. The domain-domain interactions in our model are entirely consistent with those present in the prototypical linear antiparallel heterotetramer as well as recently reported inter-strand chemical crosslinks. The model is consistent with all known physical properties of spectrin, and upon full extension our Chinese Finger Trap Model reduces to the ~180-200 nm molecular model currently in common use. Spectrins are cytoskeletal and scaffolding proteins ubiquitously expressed in essentially all cell-types. Despite unequivocal evidence for a short physiological length of ~55–65 nm at rest, spectrin is typically represented as an extended ~200 nm molecule that is implied based on crystallographic structures of a number of tandem repeats. Here, we incorporate previously reported biochemical and crystallographic data with structural mass spectroscopy and electron microscopic data to derive a detailed, experimentally-supported quaternary structure of the physiological compact form of spectrin. In addition to explaining spectrin’s physiological resting length (~55–65 nm), our model provides a mechanism by which spectrin can undergo a seamless three-fold extension, which is an experimentally observed property that is responsible for restoration of cell shape after mechanical deformation.
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Affiliation(s)
- Jeffrey W. Brown
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, Massachusetts, United States of America
- Internal Medicine Residency Program, University of Pittsburgh Medical Center, UPMC Montefiore Hospital, Pittsburgh, Pennsylvania, United States of America
| | - Esther Bullitt
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Sira Sriswasdi
- Center for Systems and Computational Biology, and Molecular and Cellular Oncogenesis Program, the Wistar Institute, Philadelphia, Pennsylvania, United States of America
- Genomics and Computational Biology Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Sandra Harper
- Center for Systems and Computational Biology, and Molecular and Cellular Oncogenesis Program, the Wistar Institute, Philadelphia, Pennsylvania, United States of America
| | - David W. Speicher
- Center for Systems and Computational Biology, and Molecular and Cellular Oncogenesis Program, the Wistar Institute, Philadelphia, Pennsylvania, United States of America
- Genomics and Computational Biology Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - C. James McKnight
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail:
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Abstract
Epithelial cells from diverse tissues, including the enterocytes that line the intestinal tract, remodel their apical surface during differentiation to form a brush border: an array of actin-supported membrane protrusions known as microvilli that increases the functional capacity of the tissue. Although our understanding of how epithelial cells assemble, stabilize, and organize apical microvilli is still developing, investigations of the biochemical and physical underpinnings of these processes suggest that cells coordinate cytoskeletal remodeling, membrane-cytoskeleton cross-linking, and extracellular adhesion to shape the apical brush border domain.
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Affiliation(s)
- Scott W Crawley
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232
| | - Mark S Mooseker
- Department of Molecular, Cellular and Developmental Biology, Department of Cell Biology, and Department of Pathology, Yale University, New Haven, CT 06520 Department of Molecular, Cellular and Developmental Biology, Department of Cell Biology, and Department of Pathology, Yale University, New Haven, CT 06520 Department of Molecular, Cellular and Developmental Biology, Department of Cell Biology, and Department of Pathology, Yale University, New Haven, CT 06520
| | - Matthew J Tyska
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232
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Abstract
The FGFR pathway triggers a wide range of key biological responses. Among others, the Breathless (Btl, Drosophila FGFR1) receptor cascade promotes cell migration during embryonic tracheal system development. However, how the actin cytoskeleton responds to Btl pathway activation to induce cell migration has remained largely unclear. Our recent results shed light into this issue by unveiling a link between the actin-bundling protein Singed (Sn) and the Btl pathway. We showed that the Btl pathway regulates sn, which leads to the stabilization of the actin bundles required for filopodia formation and actin cytoskeleton rearrangement. This regulation contributes to tracheal migration, tracheal branch fusion and tracheal cell elongation. Parallel actin bundles (PABs) are usually cross-linked by more than one actin-bundling protein. Accordingly, we have also shown that sn synergistically interacts with forked (f), another actin crosslinker. In this Extra View we extend f analysis and hypothesize how both actin-bundling proteins may act together to regulate the PABs during tracheal embryonic development. Although both proteins are required for similar tracheal events, we suggest that Sn is essential for actin bundle initiation and stiffening, while F is required for the lengthening and further stabilization of the PABs.
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Affiliation(s)
- Pilar Okenve-Ramos
- a Institut de Biologia Molecular de Barcelona-CSIC ; Baldiri Reixac ; Barcelona , Spain
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Medaka villin 1-like protein (VILL) is associated with the formation of microvilli induced by decreasing salinities in the absorptive ionocytes. Front Zool 2014; 11:2. [PMID: 24410933 PMCID: PMC3896669 DOI: 10.1186/1742-9994-11-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 12/30/2013] [Indexed: 11/19/2022] Open
Abstract
Introduction Villin 1 is an actin-regulatory protein involved in the formation of microvilli of mammalian enterocytes. The microvilli, finger-like protrusions, are more abundant on the apical surfaces of gill ionocytes in various freshwater (FW) teleosts than in seawater (SW) fishes. However, the plasticity in the mechanisms of microvillus formation in the gill ionocytes are poorly understood, and the actin-regulatory proteins involved in the formation of microvilli have not been identified in fishes. The present study used the euryhaline medaka (Oryzias dancena) as a model to explore the role of a homolog of villin 1 in the actin-organization of cellular morphologies induced by decreasing salinities. Results By ultrastructural observation, there are numerous actin filaments organized on the apical cortex of ion-absorptive ionocytes in the FW-acclimated medaka. From gills of the euryhaline medaka, we have identified the VILL sequence. The phylogenetic tree and functional domains suggest that VILL is the homolog of villin 1 in fishes. Immunofluorescence using a specific antibody revealed that VILL was specifically localized to the apical region of gill ionocytes along with microvilli in the FW medaka, but not in SW fish. The expression levels of Odvill mRNA and VILL protein were higher in the gills of the FW individuals than in the SW group and were induced when fish were transferred from SW to FW. A morpholino oligonucleotide for VILL knockdown eliminated the apical protrusions of ionocytes and pavement cells in the trunk epithelia of embryos. Conclusions From a novel aspect of cytoskeletal functions, our findings highlighted the important role of VILL protein in the ionoregulation of aquatic vertebrates in response to different osmotic challenges. This study is the first to show that the expression of VILL is associated with the formation of microvilli in the absorptive ionocytes of a euryhaline fish. Loss-of-function experiments showed that the distribution of VILL may represent the molecular link between the cytoskeletal organization and cellular morphology of the absorptive ionocytes during hypoosmotic adaptation in aquatic vertebrates.
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Engineered Nanoparticles Induced Brush Border Disruption in a Human Model of the Intestinal Epithelium. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 811:55-72. [DOI: 10.1007/978-94-017-8739-0_4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Aristaeus de Asis M, Pires M, Lyon K, Vogl AW. A network of spectrin and plectin surrounds the actin cuffs of apical tubulobulbar complexes in the rat. SPERMATOGENESIS 2013; 3:e25733. [PMID: 24381803 PMCID: PMC3861171 DOI: 10.4161/spmg.25733] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 07/10/2013] [Accepted: 07/11/2013] [Indexed: 11/19/2022]
Abstract
Tubulobulbar complexes (TBCs) are actin-related endocytic structures that internalize intercellular junctions in the seminiferous epithelium. The structures consist of elongate tubular projections of the attached plasma membranes of two adjacent cells that project into Sertoli cells. This double membrane core is cuffed by a dentritic actin network and is capped at its end by a clathrin-coated pit. Here we explore the possibility that elements of the spectrin cytoskeleton are associated with clusters of tubulobulbar complexes that develop at adhesion junctions between late spermatids and Sertoli cells at the apex of the epithelium, and extend what is known about the distribution of plectin at the sites. Cryo-sections of perfusion-fixed testes and apical processes of Sertoli cells mechanically dissociated from perfusion-fixed testes were probed for spectrin, EPB41, and actin and analyzed using conventional fluorescence microscopy and confocal microscopy. Data sets from confocal microscopy were analyzed further in three-dimensional reconstructions using computer software. Additional apical Sertoli cell processes were probed for plectin and analyzed using conventional fluorescence microscopy. Antibodies generated against elements of the spectrin cytoskeleton react with material around and between the actin cuffs of tubulobulbar complexes, but appear excluded from the actin cuffs themselves. A similar staining pattern occurs with a probe for plectin. Immunoelectron microscopy confirmed the staining patterns observed by fluourescence microscopy. Based on our results, we suggest that a network of spectrin and plectin forms a scaffold around tubulobulbar complexes that may provide support for the actin network that cuffs each complex and also link adjacent complexes together.
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Affiliation(s)
| | - Manuel Pires
- Faculte des Sciences Fondamentales et Appliquees; Universite de Poitiers; Poitiers, France
| | - Kevin Lyon
- Department of Cellular and Physiological Sciences; Faculty of Medicine; University of British Columbia; BC Canada
| | - A Wayne Vogl
- Department of Cellular and Physiological Sciences; Faculty of Medicine; University of British Columbia; BC Canada
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Yang J, Singh V, Cha B, Chen TE, Sarker R, Murtazina R, Jin S, Zachos NC, Patterson GH, Tse CM, Kovbasnjuk O, Li X, Donowitz M. NHERF2 protein mobility rate is determined by a unique C-terminal domain that is also necessary for its regulation of NHE3 protein in OK cells. J Biol Chem 2013; 288:16960-16974. [PMID: 23612977 DOI: 10.1074/jbc.m113.470799] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Na(+)/H(+) exchanger regulatory factor (NHERF) proteins are a family of PSD-95/Discs-large/ZO-1 (PDZ)-scaffolding proteins, three of which (NHERFs 1-3) are localized to the brush border in kidney and intestinal epithelial cells. All NHERF proteins are involved in anchoring membrane proteins that contain PDZ recognition motifs to form multiprotein signaling complexes. In contrast to their predicted immobility, NHERF1, NHERF2, and NHERF3 were all shown by fluorescence recovery after photobleaching/confocal microscopy to be surprisingly mobile in the microvilli of the renal proximal tubule OK cell line. Their diffusion coefficients, although different among the three, were all of the same magnitude as that of the transmembrane proteins, suggesting they are all anchored in the microvilli but to different extents. NHERF3 moves faster than NHERF1, and NHERF2 moves the slowest. Several chimeras and mutants of NHERF1 and NHERF2 were made to determine which part of NHERF2 confers the slower mobility rate. Surprisingly, the slower mobility rate of NHERF2 was determined by a unique C-terminal domain, which includes a nonconserved region along with the ezrin, radixin, moesin (ERM) binding domain. Also, this C-terminal domain of NHERF2 determined its greater detergent insolubility and was necessary for the formation of larger multiprotein NHERF2 complexes. In addition, this NHERF2 domain was functionally significant in NHE3 regulation, being necessary for stimulation by lysophosphatidic acid of activity and increased mobility of NHE3, as well as necessary for inhibition of NHE3 activity by calcium ionophore 4-Br-A23187. Thus, multiple functions of NHERF2 require involvement of an additional domain in this protein.
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Affiliation(s)
- Jianbo Yang
- Department of Medicine, Division of Gastroenterology, Baltimore, Maryland 21205
| | - Varsha Singh
- Department of Medicine, Division of Gastroenterology, Baltimore, Maryland 21205
| | - Boyoung Cha
- Department of Medicine, Division of Gastroenterology, Baltimore, Maryland 21205
| | - Tian-E Chen
- Department of Medicine, Division of Gastroenterology, Baltimore, Maryland 21205
| | - Rafiquel Sarker
- Department of Medicine, Division of Gastroenterology, Baltimore, Maryland 21205
| | - Rakhilya Murtazina
- Department of Medicine, Division of Gastroenterology, Baltimore, Maryland 21205
| | - Shi Jin
- Department of Medicine, Division of Gastroenterology, Baltimore, Maryland 21205
| | - Nicholas C Zachos
- Department of Medicine, Division of Gastroenterology, Baltimore, Maryland 21205
| | - George H Patterson
- Biophotonics Section, National Institute of Biomedical Imaging and Bioengineering, NIH, Bethesda, Maryland 20892
| | - C Ming Tse
- Department of Medicine, Division of Gastroenterology, Baltimore, Maryland 21205
| | - Olga Kovbasnjuk
- Department of Medicine, Division of Gastroenterology, Baltimore, Maryland 21205
| | - Xuhang Li
- Department of Medicine, Division of Gastroenterology, Baltimore, Maryland 21205
| | - Mark Donowitz
- Department of Medicine, Division of Gastroenterology, Baltimore, Maryland 21205; Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
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Chlamydia trachomatis Tarp harbors distinct G and F actin binding domains that bundle actin filaments. J Bacteriol 2012. [PMID: 23204471 DOI: 10.1128/jb.01768-12] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
All species of Chlamydia undergo a unique developmental cycle that transitions between extracellular and intracellular environments and requires the capacity to invade new cells for dissemination. A chlamydial protein called Tarp has been shown to nucleate actin in vitro and is implicated in bacterial entry into human cells. Colocalization studies of ectopically expressed enhanced green fluorescent protein (EGFP)-Tarp indicate that actin filament recruitment is restricted to the C-terminal half of the effector protein. Actin filaments are presumably associated with Tarp via an actin binding alpha helix that is also required for actin nucleation in vitro, but this has not been investigated. Tarp orthologs from C. pneumoniae, C. muridarum, and C. caviae harbor between 1 and 4 actin binding domains located in the C-terminal half of the protein, but C. trachomatis serovar L2 has only one characterized domain. In this work, we examined the effects of domain-specific mutations on actin filament colocalization with EGFP-Tarp. We now demonstrate that actin filament colocalization with Tarp is dependent on two novel F-actin binding domains that endow the Tarp effector with actin-bundling activity. Furthermore, Tarp-mediated actin bundling did not require actin nucleation, as the ability to bundle actin filaments was observed in mutant Tarp proteins deficient in actin nucleation. These data shed molecular insight on the complex cytoskeletal rearrangements required for C. trachomatis entry into host cells.
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Enterohaemorrhagic Escherichia coli requires the spectrin cytoskeleton for efficient attachment and pedestal formation on host cells. Microb Pathog 2012; 52:149-56. [DOI: 10.1016/j.micpath.2011.12.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 12/01/2011] [Accepted: 12/03/2011] [Indexed: 12/12/2022]
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Stevenson RP, Veltman D, Machesky LM. Actin-bundling proteins in cancer progression at a glance. J Cell Sci 2012; 125:1073-9. [PMID: 22492983 DOI: 10.1242/jcs.093799] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- Richard P Stevenson
- The Beatson Institute for Cancer Research, Garscube Estate, Switchback Rd, Bearsden, Glasgow G61 1BD, UK
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Soplop NH, Cheng YS, Kramer SG. Roundabout is required in the visceral mesoderm for proper microvillus length in the hindgut epithelium. Dev Dyn 2012; 241:759-69. [PMID: 22334475 DOI: 10.1002/dvdy.23749] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/16/2012] [Indexed: 11/11/2022] Open
Abstract
INTRODUCTION In this study we examined Roundabout signaling in the Drosophila embryonic hindgut. RESULTS Slit and its receptors Roundabout (Robo) and Roundabout 2 (Robo2) localize to discrete regions in the hindgut epithelium and surrounding visceral mesoderm. Loss of robo, robo2 or slit did not disrupt overall hindgut patterning. However, slit and robo mutants showed a decrease in microvillus length on the boundary cells of the hindgut epithelium. Rescue and overexpression analysis revealed that robo is specifically required in the visceral mesoderm for correct microvillus length in the underlying hindgut epithelium. Expression of robo in the visceral mesoderm of robo mutant embryos restored normal microvillus length, while overexpression of robo resulted in an increase in microvillus length. Microvillus length was also increased in robo2 mutants suggesting that robo2 may antagonize robo function in the hindgut. CONCLUSION Together, these results establish a novel, dose-dependent role for Robo in regulating microvilli growth and provide in vivo evidence for the role of the visceral mesoderm in controlling morphological changes in the underlying intestinal epithelium.
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Affiliation(s)
- Nadine H Soplop
- Department of Pathology and Laboratory Medicine, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, New Jersey 08854-8020, USA
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Plastin family of actin-bundling proteins: its functions in leukocytes, neurons, intestines, and cancer. Int J Cell Biol 2012; 2012:213492. [PMID: 22262972 PMCID: PMC3259490 DOI: 10.1155/2012/213492] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 09/29/2011] [Accepted: 10/04/2011] [Indexed: 11/25/2022] Open
Abstract
Sophisticated regulation of the actin cytoskeleton by a variety of actin-binding proteins is essential for eukaryotic cells to perform their diverse functions. The plastin (also know, as fimbrin) protein family belongs to actin-bundling proteins, and the protein family is evolutionarily conserved and expressed in yeast, plant, and animal cells. Plastins are characterized by EF-hand Ca2+-binding domains and actin-binding domains and can cross-link actin filaments into higher-order assemblies like bundles. Three isoforms have been identified in mammals. T-plastin is expressed in cells from solid tissues, such as neurons in the brain. I-plastin expression is restricted to intestine and kidney; the isoform plays a vital role in the function of absorptive epithelia in these organs. L-plastin is expressed in hematopoietic cell lineages and in many types of cancer cells; the isoform is thus considered to be a useful biomarker for cancer.
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Revenu C, Ubelmann F, Hurbain I, El-Marjou F, Dingli F, Loew D, Delacour D, Gilet J, Brot-Laroche E, Rivero F, Louvard D, Robine S. A new role for the architecture of microvillar actin bundles in apical retention of membrane proteins. Mol Biol Cell 2011; 23:324-36. [PMID: 22114352 PMCID: PMC3258176 DOI: 10.1091/mbc.e11-09-0765] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The bundled architecture of actin filaments is not needed for intestinal microvillar morphogenesis, as shown in knockout mice devoid of microvillar actin-bundling proteins. This architecture is essential for the apical anchorage of digestive proteins, probably via the recruitment of key players in apical retention, such as myosin-1a, and, as a result, for intestinal physiology. Actin-bundling proteins are identified as key players in the morphogenesis of thin membrane protrusions. Until now, functional redundancy among the actin-bundling proteins villin, espin, and plastin-1 has prevented definitive conclusions regarding their role in intestinal microvilli. We report that triple knockout mice lacking these microvillar actin-bundling proteins suffer from growth delay but surprisingly still develop microvilli. However, the microvillar actin filaments are sparse and lack the characteristic organization of bundles. This correlates with a highly inefficient apical retention of enzymes and transporters that accumulate in subapical endocytic compartments. Myosin-1a, a motor involved in the anchorage of membrane proteins in microvilli, is also mislocalized. These findings illustrate, in vivo, a precise role for local actin filament architecture in the stabilization of apical cargoes into microvilli. Hence, the function of actin-bundling proteins is not to enable microvillar protrusion, as has been assumed, but to confer the appropriate actin organization for the apical retention of proteins essential for normal intestinal physiology.
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Affiliation(s)
- Céline Revenu
- Unité Mixte de Recherche 144, Centre National de la Recherche Scientifique, Institut Curie, 75248 Paris, Cedex 05, France.
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Lai Y, Riley K, Cai A, Leong JM, Herman IM. Calpain mediates epithelial cell microvillar effacement by enterohemorrhagic Escherichia coli. Front Microbiol 2011; 2:222. [PMID: 22073041 PMCID: PMC3210503 DOI: 10.3389/fmicb.2011.00222] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 10/20/2011] [Indexed: 11/13/2022] Open
Abstract
A member of the attaching and effacing (AE) family of pathogens, enterohemorrhagic Escherichia coli (EHEC) induces dramatic changes to the intestinal cell cytoskeleton, including effacement of microvilli. Effacement by the related pathogen enteropathogenic E. coli (EPEC) requires the activity of the Ca+2-dependent host protease, calpain, which participates in a variety of cellular processes, including cell adhesion and motility. We found that EHEC infection results in an increase in epithelial (CaCo-2a) cell calpain activity and that EHEC-induced microvillar effacement was blocked by ectopic expression of calpastatin, an endogenous calpain inhibitor, or by pretreatment of intestinal cells with a cell-penetrating version of calpastatin. In addition, ezrin, a known calpain substrate that links the plasma membrane to axial actin filaments in microvilli, was cleaved in a calpain-dependent manner during EHEC infection and lost from its normal locale within microvilli. Calpain may be a central conduit through which EHEC and other AE pathogens induce enterocyte cytoskeletal remodeling and exert their pathogenic effects.
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Affiliation(s)
- Yushuan Lai
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School Worcester, MA, USA
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Khurana S, George SP. The role of actin bundling proteins in the assembly of filopodia in epithelial cells. Cell Adh Migr 2011; 5:409-20. [PMID: 21975550 PMCID: PMC3218608 DOI: 10.4161/cam.5.5.17644] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Accepted: 08/05/2011] [Indexed: 01/22/2023] Open
Abstract
The goal of this review is to highlight how emerging new models of filopodia assembly, which include tissue specific actin-bundling proteins, could provide more comprehensive representations of filopodia assembly that would describe more adequately and effectively the complexity and plasticity of epithelial cells. This review also describes how the true diversity of actin bundling proteins must be considered to predict the far-reaching significance and versatile functions of filopodia in epithelial cells.
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Affiliation(s)
- Seema Khurana
- Department of Biology and Biochemistry, University of Houston, Houston, TX, USA.
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Lanzano L, Lei T, Okamura K, Giral H, Caldas Y, Masihzadeh O, Gratton E, Levi M, Blaine J. Differential modulation of the molecular dynamics of the type IIa and IIc sodium phosphate cotransporters by parathyroid hormone. Am J Physiol Cell Physiol 2011; 301:C850-61. [PMID: 21593452 DOI: 10.1152/ajpcell.00412.2010] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The kidney is a key regulator of phosphate homeostasis. There are two predominant renal sodium phosphate cotransporters, NaPi2a and NaPi2c. Both are regulated by parathyroid hormone (PTH), which decreases the abundance of the NaPi cotransporters in the apical membrane of renal proximal tubule cells. The time course of PTH-induced removal of the two cotransporters from the apical membrane, however, is markedly different for NaPi2a compared with NaPi2c. In animals and in cell culture, PTH treatment results in almost complete removal of NaPi2a from the brush border (BB) within 1 h whereas for NaPi2c this process in not complete until 4 to 8 h after PTH treatment. The reason for this is poorly understood. We have previously shown that the unconventional myosin motor myosin VI is required for PTH-induced removal of NaPi2a from the proximal tubule BB. Here we demonstrate that myosin VI is also necessary for PTH-induced removal of NaPi2c from the apical membrane. In addition, we show that, while at baseline the two cotransporters have similar diffusion coefficients within the membrane, after PTH addition the diffusion coefficient for NaPi2a initially exceeds that for NaPi2c. Thus NaPi2c appears to remain "tethered" in the apical membrane for longer periods of time after PTH treatment, accounting, at least in part, for the difference in response times to PTH of NaPi2a versus NaPi2c.
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Affiliation(s)
- Luca Lanzano
- Laboratory for Fluorescence Dynamics, University of California, Irvine, USA
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Ruetz T, Cornick S, Guttman JA. The spectrin cytoskeleton is crucial for adherent and invasive bacterial pathogenesis. PLoS One 2011; 6:e19940. [PMID: 21603579 PMCID: PMC3095645 DOI: 10.1371/journal.pone.0019940] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Accepted: 04/18/2011] [Indexed: 11/18/2022] Open
Abstract
Various enteric bacterial pathogens target the host cell cytoskeletal machinery as a crucial event in their pathogenesis. Despite thorough studies detailing strategies microbes use to exploit these components of the host cell, the role of the spectrin-based cytoskeleton has been largely overlooked. Here we show that the spectrin cytoskeleton is a host system that is hijacked by adherent (Entropathogenic Escherichia coli [EPEC]), invasive triggering (Salmonella enterica serovar Typhimurium [S. Typhimurium]) and invasive zippering (Listeria monocytogenes) bacteria. We demonstrate that spectrin cytoskeletal proteins are recruited to EPEC pedestals, S. Typhimurium membrane ruffles and Salmonella containing vacuoles (SCVs), as well as sites of invasion and comet tail initiation by L. monocytogenes. Spectrin was often seen co-localizing with actin filaments at the cell periphery, however a disconnect between the actin and spectrin cytoskeletons was also observed. During infections with S. Typhimurium ΔsipA, actin-rich membrane ruffles at characteristic sites of bacterial invasion often occurred in the absence of spectrin cytoskeletal proteins. Additionally, early in the formation of L. monocytogenes comet tails, spectrin cytoskeletal elements were recruited to the surface of the internalized bacteria independent of actin filaments. Further studies revealed the presence of the spectrin cytoskeleton during SCV and Listeria comet tail formation, highlighting novel cytoplasmic roles for the spectrin cytoskeleton. SiRNA targeted against spectrin and the spectrin-associated proteins severely diminished EPEC pedestal formation as well as S. Typhimurium and L. monocytogenes invasion. Ultimately, these findings identify the spectrin cytoskeleton as a ubiquitous target of enteric bacterial pathogens and indicate that this cytoskeletal system is critical for these infections to progress.
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Affiliation(s)
- Tyson Ruetz
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Steve Cornick
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Julian Andrew Guttman
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
- * E-mail:
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