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Miner MV, Rauch I. Why put yourself on a pedestal? The pathogenic role of the A/E pedestal. Infect Immun 2024; 92:e0048923. [PMID: 38591884 PMCID: PMC11384751 DOI: 10.1128/iai.00489-23] [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] [Indexed: 04/10/2024] Open
Abstract
Certain Escherichia coli (E. coli) strains are attaching and effacing (A/E) lesion pathogens that primarily infect intestinal epithelial cells. They cause actin restructuring and polymerization within the host cell to create an actin-rich protrusion below the site of adherence, termed the pedestal. Although there is clarity on the pathways initiating pedestal formation, the underlying purpose(s) of the pedestal remains ambiguous. The conservation of pedestal-forming activity across multiple pathogens and redundancy in formation pathways indicate a pathogenic advantage. However, few decisive conclusions have been drawn, given that the results vary between model systems. Some research argues that the pedestal increases the colonization capability of the bacterium. These studies utilize A/E pathogens specifically deficient in pedestal formation to evaluate adhesion and intestinal colonization following infection. There have been many proposed mechanisms for the colonization benefit conferred by the pedestal. One suggested benefit is that the pedestal allows for direct cytosolic anchoring through incorporation of the established host cortical actin, causing a stable link between the pathogen and cell structure. The pedestal may confer enhanced motility, as enteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli (EHEC) are better able to migrate on the surface of host cells and infect neighboring cells in the presence of the pedestal. Additionally, some research suggests that the pedestal improves effector delivery. This review will investigate the purpose of pedestal formation using evidence from recent literature and will critically evaluate the methodology and model systems. Most importantly, we will contextualize the proposed functions to reconcile potential synergistic effects.
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Affiliation(s)
- M. V. Miner
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, USA
| | - I. Rauch
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, USA
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Olatona OA, Choudhury SR, Kresman R, Heckman CA. Candidate proteins interacting with cytoskeleton in cells from the basal airway epithelium in vitro. Front Mol Biosci 2024; 11:1423503. [PMID: 39139811 PMCID: PMC11319710 DOI: 10.3389/fmolb.2024.1423503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Accepted: 06/24/2024] [Indexed: 08/15/2024] Open
Abstract
Introduction: The cytoskeleton consists of actin, microtubules, septins, and intermediate filaments and, in most cells, is anchored to an extracellular matrix. Each cell has a unique arrangement of this network and readjusts it from time to time. To investigate the regulation of these reorganizations, we identified interactors from extracts of four cultured lines representing basal cells from the airway epithelium. Methods: After immunoprecipitation with an antibody against keratin 17, samples were processed by liquid chromatography and tandem mass spectrometry. Samples not undergoing antibody-mediated capture were processed in parallel. Results: The main keratins of basal cells, namely, Krt14 (type I) and Krt5 (type II), constituted 67% of the total keratin recovered. Several other intermediate filament proteins, nestin, lamin-B1, and prelamin A/C, were present but not enriched upon immunoprecipitation. Although the class of armadillo-repeat proteins was represented by beta-catenin1 and plakoglobin, other desmosome plaque constituents were absent. Large cytolinkers were represented by the spectraplakin, microtubule-actin cross-linking factor (Macf1), which was enriched by immunoprecipitation, and the plakin, plectin, which was not enriched. Subunits of actin filaments and microtubules, along with numerous proteins associated with them, were recovered in both immunoprecipitated samples and those lacking the capture step. Coefficients of determination were computed based on abundance. The actin-associated proteins, alpha-spectrin and brain-specific angiogenesis inhibitor (Baiaip2l), were modestly correlated with keratin abundance but highly correlated with one another and with the keratin-binding protein, annexin A2. This interaction network resembled the pedestal formed by pathogenic Escherichia coli. Microtubule-associated proteins, dynamin 1-like protein and cytoplasmic dynein 1 heavy chain (Dync1h1), were enriched by immunoprecipitation, suggesting association with keratins, whereas kinesin-1 heavy chain and microtubule-associated protein retinitis pigmentosa 1 (EB1), were not enriched. Dync1h1 abundance was negatively correlated with that of all the septins, suggesting resemblance to a known antagonistic septin-dynein 1 relationship on microtubules. Conclusion: The cell lines showed remarkable uniformity with respect to the candidates interacting with cytoskeleton. The alpha-spectrin-Baiap2l network may link actin filaments to keratin precursor particles. A smaller interaction network centered on Dync1h1 was negatively correlated with all spectrin-Baiap2l constituents, suggesting that it and its binding partners are excluded from the pedestal-like domain.
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Affiliation(s)
- Olusola A. Olatona
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH, United States
| | - Sayantan R. Choudhury
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH, United States
| | - Ray Kresman
- Department of Computer Science, Bowling Green State University, Bowling Green, OH, United States
| | - Carol A. Heckman
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH, United States
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Medrano E, Merselis DG, Bellantuono AJ, Rodriguez-Lanetty M. Proteomic Basis of Symbiosis: A Heterologous Partner Fails to Duplicate Homologous Colonization in a Novel Cnidarian- Symbiodiniaceae Mutualism. Front Microbiol 2019; 10:1153. [PMID: 31214134 PMCID: PMC6554683 DOI: 10.3389/fmicb.2019.01153] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 05/06/2019] [Indexed: 12/29/2022] Open
Abstract
Reef corals and sea anemones form symbioses with unicellular symbiotic dinoflagellates. The molecular circumventions that underlie the successful intracellular colonization of hosts by symbionts are still largely unknown. We conducted proteomic analyses to determine molecular differences of Exaiptasia pallida anemones colonized by physiologically different symbiont species, in comparison with symbiont-free (aposymbiotic) anemones. We compared one homologous species, Symbiodinium linucheae, that is natively associated with the clonal Exaiptasia strain (CC7) to another heterologous species, Durusdinium trenchii, a thermally tolerant species that colonizes numerous coral species. This approach allowed the discovery of a core set of host genes that are differentially regulated as a function of symbiosis regardless of symbiont species. The findings revealed that symbiont colonization at higher densities requires circumvention of the host cellular immunological response, enhancement of ammonium regulation, and suppression of phagocytosis after a host cell in colonized. Furthermore, the heterologous symbionts failed to duplicate the same level of homologous colonization within the host, evidenced by substantially lower symbiont densities. This reduced colonization of D. trenchii correlated with its inability to circumvent key host systems including autophagy-suppressing modulators, cytoskeletal alteration, and isomerase activity. The larger capability of host molecular circumvention by homologous symbionts could be the result of a longer evolutionary history of host/symbiont interactions, which translates into a more finely tuned symbiosis. These findings are of great importance within the context of the response of reef corals to climate change since it has been suggested that coral may acclimatize to ocean warming by changing their dominant symbiont species.
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Mei C, Wang H, Liao Q, Wang L, Cheng G, Wang H, Zhao C, Zhao S, Song J, Guang X, Liu GE, Li A, Wu X, Wang C, Fang X, Zhao X, Smith SB, Yang W, Tian W, Gui L, Zhang Y, Hill RA, Jiang Z, Xin Y, Jia C, Sun X, Wang S, Yang H, Wang J, Zhu W, Zan L. Genetic Architecture and Selection of Chinese Cattle Revealed by Whole Genome Resequencing. Mol Biol Evol 2017; 35:688-699. [PMID: 29294071 DOI: 10.1093/molbev/msx322] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The bovine genetic resources in China are diverse, but their value and potential are yet to be discovered. To determine the genetic diversity and population structure of Chinese cattle, we analyzed the whole genomes of 46 cattle from six phenotypically and geographically representative Chinese cattle breeds, together with 18 Red Angus cattle genomes, 11 Japanese black cattle genomes and taurine and indicine genomes available from previous studies. Our results showed that Chinese cattle originated from hybridization between Bos taurus and Bos indicus. Moreover, we found that the level of genetic variation in Chinese cattle depends upon the degree of indicine content. We also discovered many potential selective sweep regions associated with domestication related to breed-specific characteristics, with selective sweep regions including genes associated with coat color (ERCC2, MC1R, ZBTB17, and MAP2K1), dairy traits (NCAPG, MAPK7, FST, ITFG1, SETMAR, PAG1, CSN3, and RPL37A), and meat production/quality traits (such as BBS2, R3HDM1, IGFBP2, IGFBP5, MYH9, MYH4, and MC5R). These findings substantially expand the catalogue of genetic variants in cattle and reveal new insights into the evolutionary history and domestication traits of Chinese cattle.
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Affiliation(s)
- Chugang Mei
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Hongcheng Wang
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Qijun Liao
- BGI Genomics, BGI-Shenzhen, Shenzhen, China
| | | | - Gong Cheng
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Hongbao Wang
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Chunping Zhao
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | | | - Jiuzhou Song
- Department of Animal and Avian Sciences, University of Maryland, Maryland, USA
| | | | - George E Liu
- Animal Genomics and Improvement Laboratory, USDA-ARS, Maryland, USA
| | - Anning Li
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Xueli Wu
- BGI Genomics, BGI-Shenzhen, Shenzhen, China
| | | | | | - Xin Zhao
- College of Animal Science and Technology, Northwest A&F University, Yangling, China.,Department of Animal Science, McGill University, Montreal, Canada
| | - Stephen B Smith
- Department of Animal Science, Texas A&M University, Texas, USA
| | - Wucai Yang
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Wanqiang Tian
- Yangling Vocational & Technical College, Yangling, China
| | - Linsheng Gui
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Yingying Zhang
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Rodney A Hill
- School of Biomedical Sciences, Charles Sturt University, New South Wales, Australia
| | - Zhongliang Jiang
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Yaping Xin
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Cunling Jia
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Xiuzhu Sun
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Shuhui Wang
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Huanming Yang
- BGI-Shenzhen, Shenzhen, China.,James D. Watson Institute of Genome Sciences, Hangzhou, China
| | - Jian Wang
- BGI-Shenzhen, Shenzhen, China.,James D. Watson Institute of Genome Sciences, Hangzhou, China
| | | | - Linsen Zan
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
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The Locus of Enterocyte Effacement and Associated Virulence Factors of Enterohemorrhagic Escherichia coli. Microbiol Spectr 2016; 2:EHEC-0007-2013. [PMID: 26104209 DOI: 10.1128/microbiolspec.ehec-0007-2013] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A subset of Shiga toxin-producing Escherichia coli strains, termed enterohemorrhagic E. coli (EHEC), is defined in part by the ability to produce attaching and effacing (A/E) lesions on intestinal epithelia. Such lesions are characterized by intimate bacterial attachment to the apical surface of enterocytes, cytoskeletal rearrangements beneath adherent bacteria, and destruction of proximal microvilli. A/E lesion formation requires the locus of enterocyte effacement (LEE), which encodes a Type III secretion system that injects bacterial proteins into host cells. The translocated proteins, termed effectors, subvert a plethora of cellular pathways to the benefit of the pathogen, for example, by recruiting cytoskeletal proteins, disrupting epithelial barrier integrity, and interfering with the induction of inflammation, phagocytosis, and apoptosis. The LEE and selected effectors play pivotal roles in intestinal persistence and virulence of EHEC, and it is becoming clear that effectors may act in redundant, synergistic, and antagonistic ways during infection. Vaccines that target the function of the Type III secretion system limit colonization of reservoir hosts by EHEC and may thus aid control of zoonotic infections. Here we review the features and functions of the LEE-encoded Type III secretion system and associated effectors of E. coli O157:H7 and other Shiga toxin-producing E. coli strains.
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He S, Hou X, Xu X, Wan C, Yin P, Liu X, Chen Y, Shu B, Liu F, Xu J. Quantitative proteomic analysis reveals heat stress-induced injury in rat small intestine via activation of the MAPK and NF-κB signaling pathways. MOLECULAR BIOSYSTEMS 2015; 11:826-34. [DOI: 10.1039/c4mb00495g] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We employed comparative proteomics to reveal a heat stress-induced injury mechanism in rat small intestine.
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7
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Vorwerk S, Krieger V, Deiwick J, Hensel M, Hansmeier N. Proteomes of host cell membranes modified by intracellular activities of Salmonella enterica. Mol Cell Proteomics 2014; 14:81-92. [PMID: 25348832 DOI: 10.1074/mcp.m114.041145] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Intracellular pathogens need to establish a growth-stimulating host niche for survival and replication. A unique feature of the gastrointestinal pathogen Salmonella enterica serovar Typhimurium is the creation of extensive membrane networks within its host. An understanding of the origin and function of these membranes is crucial for the development of new treatment strategies. However, the characterization of this compartment is very challenging, and only fragmentary knowledge of its composition and biogenesis exists. Here, we describe a new proteome-based approach to enrich and characterize Salmonella-modified membranes. Using a Salmonella mutant strain that does not form this unique membrane network as a reference, we identified a high-confidence set of host proteins associated with Salmonella-modified membranes. This comprehensive analysis allowed us to reconstruct the interactions of Salmonella with host membranes. For example, we noted that Salmonella redirects endoplasmic reticulum (ER) membrane trafficking to its intracellular niche, a finding that has not been described for Salmonella previously. Our system-wide approach therefore has the potential to rapidly close gaps in our knowledge of the infection process of intracellular pathogens and demonstrates a hitherto unrecognized complexity in the formation of Salmonella host niches.
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Affiliation(s)
- Stephanie Vorwerk
- From the ‡Division of Microbiology, School of Biology/Chemistry, University of Osnabrück, 49076 Osnabrück, Germany
| | - Viktoria Krieger
- From the ‡Division of Microbiology, School of Biology/Chemistry, University of Osnabrück, 49076 Osnabrück, Germany
| | - Jörg Deiwick
- From the ‡Division of Microbiology, School of Biology/Chemistry, University of Osnabrück, 49076 Osnabrück, Germany
| | - Michael Hensel
- From the ‡Division of Microbiology, School of Biology/Chemistry, University of Osnabrück, 49076 Osnabrück, Germany
| | - Nicole Hansmeier
- From the ‡Division of Microbiology, School of Biology/Chemistry, University of Osnabrück, 49076 Osnabrück, Germany
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Kast DJ, Yang C, Disanza A, Boczkowska M, Madasu Y, Scita G, Svitkina T, Dominguez R. Mechanism of IRSp53 inhibition and combinatorial activation by Cdc42 and downstream effectors. Nat Struct Mol Biol 2014; 21:413-22. [PMID: 24584464 DOI: 10.1038/nsmb.2781] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 01/28/2014] [Indexed: 12/16/2022]
Abstract
The Rho family GTPase effector IRSp53 has essential roles in filopodia formation and neuronal development, but its regulatory mechanism is poorly understood. IRSp53 contains a membrane-binding BAR domain followed by an unconventional CRIB motif that overlaps with a proline-rich region (CRIB-PR) and an SH3 domain that recruits actin cytoskeleton effectors. Using a fluorescence reporter assay, we show that human IRSp53 adopts a closed inactive conformation that opens synergistically with the binding of human Cdc42 to the CRIB-PR and effector proteins, such as the tumor-promoting factor Eps8, to the SH3 domain. The crystal structure of Cdc42 bound to the CRIB-PR reveals a new mode of effector binding to Rho family GTPases. Structure-inspired mutations disrupt autoinhibition and Cdc42 binding in vitro and decouple Cdc42- and IRSp53-dependent filopodia formation in cells. The data support a combinatorial mechanism of IRSp53 activation.
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Affiliation(s)
- David J Kast
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Changsong Yang
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | | | - Malgorzata Boczkowska
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Yadaiah Madasu
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Giorgio Scita
- 1] FIRC Institute of Molecular Oncology, Milan, Italy. [2] Department of Health Sciences, University of Milan School of Medicine, Milan, Italy
| | - Tatyana Svitkina
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Roberto Dominguez
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Zhang R, Zhang C, Zhao Q, Li D. Spectrin: structure, function and disease. SCIENCE CHINA-LIFE SCIENCES 2013; 56:1076-85. [PMID: 24302288 DOI: 10.1007/s11427-013-4575-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 03/20/2013] [Indexed: 01/23/2023]
Abstract
Spectrin is a large, cytoskeletal, and heterodimeric protein composed of modular structure of α and β subunits, it typically contains 106 contiguous amino acid sequence motifs called "spectrin repeats". Spectrin is crucial for maintaining the stability and structure of the cell membrane and the shape of a cell. Moreover, it contributes to diverse cell functions such as cell adhesion, cell spreading, and the cell cycle. Mutations of spectrin lead to various human diseases such as hereditary hemolytic anemia, type 5 spinocerebellar ataxia, cancer, as well as others. This review focuses on recent advances in determining the structure and function of spectrin as well as its role in disease.
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Affiliation(s)
- Rui Zhang
- Jiangsu Engineering Research Center for microRNA Biology and Biotechnology, State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210093, China
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10
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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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Insulin receptor tyrosine kinase substrate activates EGFR/ERK signalling pathway and promotes cell proliferation of hepatocellular carcinoma. Cancer Lett 2013; 337:96-106. [PMID: 23693078 DOI: 10.1016/j.canlet.2013.05.019] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2013] [Revised: 05/07/2013] [Accepted: 05/14/2013] [Indexed: 11/21/2022]
Abstract
Insulin receptor tyrosine kinase substrate (IRTKS) is closely associated with actin remodelling and membrane protrusion, but its role in the pathogenesis of malignant tumours, including hepatocellular carcinoma (HCC), is still unknown. In this study, we showed that IRTKS was frequently upregulated in HCC samples, and its expression level was significantly associated with tumour size. Enforced expression of IRTKS in human HCC cell lines significantly promoted their proliferation and colony formation in vitro, and their capacity to develop tumour xenografts in vivo, whereas knockdown of IRTKS resulted in the opposite effects. Furthermore, the bromodeoxyuridine (BrdU) incorporation analyses and propidium iodide staining indicated that IRTKS can promote the entry into S phase of cell cycle progression. Significantly, IRTKS can interact with epidermal growth factor receptor (EGFR), results in the phosphorylation of extracellular signal-regulated kinase (ERK). By contrast, inhibition of ERK activation can attenuate the effects of IRTKS overexpression on cellular proliferation. Taken together, these data demonstrate that IRTKS promotes the proliferation of HCC cells by enhancing EGFR-ERK signalling pathway.
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Actin cytoskeleton manipulation by effector proteins secreted by diarrheagenic Escherichia coli pathotypes. BIOMED RESEARCH INTERNATIONAL 2012; 2013:374395. [PMID: 23509714 PMCID: PMC3591105 DOI: 10.1155/2013/374395] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 10/22/2012] [Indexed: 11/18/2022]
Abstract
The actin cytoskeleton is a dynamic structure necessary for cell and tissue organization, including the maintenance of epithelial barriers. Disruption of the epithelial barrier coincides with alterations of the actin cytoskeleton in several disease states. These disruptions primarily affect the paracellular space, which is normally regulated by tight junctions. Thereby, the actin cytoskeleton is a common and recurring target of bacterial virulence factors. In order to manipulate the actin cytoskeleton, bacteria secrete and inject toxins and effectors to hijack the host cell machinery, which interferes with host-cell pathways and with a number of actin binding proteins. An interesting model to study actin manipulation by bacterial effectors is Escherichia coli since due to its genome plasticity it has acquired diverse genetic mobile elements, which allow having different E. coli varieties in one bacterial species. These E. coli pathotypes, including intracellular and extracellular bacteria, interact with epithelial cells, and their interactions depend on a specific combination of virulence factors. In this paper we focus on E. coli effectors that mimic host cell proteins to manipulate the actin cytoskeleton. The study of bacterial effector-cytoskeleton interaction will contribute not only to the comprehension of the molecular causes of infectious diseases but also to increase our knowledge of cell biology.
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