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Cortactin Mediates Apoptosis of Gastric Epithelial Cells Induced by VacA Protein of Helicobacter pylori. Dig Dis Sci 2016; 61:80-90. [PMID: 26289258 DOI: 10.1007/s10620-015-3836-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 07/30/2015] [Indexed: 12/11/2022]
Abstract
BACKGROUND Vacuolating cytotoxin antigen (VacA) is one of the major virulence factors in Helicobacter pylori (H. pylori), which is responsible for cell vacuolar degeneration and apoptotic cell death. A candidate host factor which mediates this process is cortactin, a protein associated with the processes of colonization and adhesion of H. pylori in gastric epithelium. AIM To investigate the role of cortactin in VacA-induced apoptosis of gastric epithelial cells. METHODS Cortactin expression and shRNA lentiviral constructs were developed and transduced into the human gastric cancer cell line, AGS. VacA protein was purified from H. pylori cultures, acid-activated, and co-incubated with the transduced cell populations. Apoptosis was detected by flow cytometry, and the levels of the pro- and anti-apoptotic proteins Bax and Bcl-2 were determined by Western blot. RESULTS Acid-activated purified VacA induced apoptosis in the parental AGS cells. Increased expression of cortactin (AGS/cortactin) led to a greater percentage of cells undergoing apoptosis. In contrast, knockdown of cortactin with shRNA (AGS/cortactin-shRNA) decreased the percentage of apoptotic cells. The protein levels of pro- and anti-apoptotic proteins Bax and Bcl-2 were increased and decreased in AGS/cortactin cells relative to the parental AGS cells. In the AGS/cortactin-shRNA cells, Bax protein levels were decreased, while Bcl-2 protein was increased. CONCLUSIONS The results indicate that cortactin is involved in the regulation of apoptosis induced by VacA in gastric cells.
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Rottner K, Stradal TEB. How distinct Arp2/3 complex variants regulate actin filament assembly. Nat Cell Biol 2015; 18:1-3. [DOI: 10.1038/ncb3293] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Stamatovic SM, Sladojevic N, Keep RF, Andjelkovic AV. PDCD10 (CCM3) regulates brain endothelial barrier integrity in cerebral cavernous malformation type 3: role of CCM3-ERK1/2-cortactin cross-talk. Acta Neuropathol 2015; 130:731-50. [PMID: 26385474 DOI: 10.1007/s00401-015-1479-z] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 09/09/2015] [Accepted: 09/10/2015] [Indexed: 10/25/2022]
Abstract
Impairment of brain endothelial barrier integrity is critical for cerebral cavernous malformation (CCM) lesion development. The current study investigates changes in tight junction (TJ) complex organization when PDCD10 (CCM3) is mutated/depleted in human brain endothelial cells. Analysis of lesions with CCM3 mutation and brain endothelial cells transfected with CCM3 siRNA (CCM3-knockdown) showed little or no increase in TJ transmembrane and scaffolding proteins mRNA expression, but proteins levels were generally decreased. CCM3-knockdown cells had a redistribution of claudin-5 and occludin from the membrane to the cytosol with no alterations in protein turnover but with diminished protein-protein interactions with ZO-1 and ZO-1 interaction with the actin cytoskeleton. The most profound effect of CCM3 mutation/depletion was on an actin-binding protein, cortactin. CCM3 depletion caused cortactin Ser-phosphorylation, dissociation from ZO-1 and actin, redistribution to the cytosol and degradation. This affected cortical actin ring organization, TJ complex stability and consequently barrier integrity, with constant hyperpermeability to inulin. A potential link between CCM3 depletion and altered cortactin was tonic activation of MAP kinase ERK1/2. ERK1/2 inhibition increased cortactin expression and incorporation into the TJ complex and improved barrier integrity. This study highlights the potential role of CCM3 in regulating TJ complex organization and brain endothelial barrier permeability.
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Tang DD. Critical role of actin-associated proteins in smooth muscle contraction, cell proliferation, airway hyperresponsiveness and airway remodeling. Respir Res 2015; 16:134. [PMID: 26517982 PMCID: PMC4628321 DOI: 10.1186/s12931-015-0296-1] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 10/22/2015] [Indexed: 01/16/2023] Open
Abstract
Asthma is characterized by airway hyperresponsiveness and airway remodeling, which are largely attributed to increased airway smooth muscle contractility and cell proliferation. It is known that both chemical and mechanical stimulation regulates smooth muscle contraction. Recent studies suggest that contractile activation and mechanical stretch induce actin cytoskeletal remodeling in smooth muscle. However, the mechanisms that control actin cytoskeletal reorganization are not completely elucidated. This review summarizes our current understanding regarding how actin-associated proteins may regulate remodeling of the actin cytoskeleton in airway smooth muscle. In particular, there is accumulating evidence to suggest that Abelson tyrosine kinase (Abl) plays a critical role in regulating airway smooth muscle contraction and cell proliferation in vitro, and airway hyperresponsiveness and remodeling in vivo. These studies indicate that Abl may be a novel target for the development of new therapy to treat asthma.
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Affiliation(s)
- Dale D Tang
- Center for Cardiovascular Sciences, Albany Medical College, 47 New Scotland Avenue, MC-8, Albany, NY, 12208, USA.
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Abstract
Objective: To determine the exact role of sodium channel proteins in migration, invasion and metastasis and understand the possible anti-invasion and anti-metastatic activity of repurposed drugs with voltage gated sodium channel blocking properties. Material and methods: A review of the published medical literature was performed searching for pharmaceuticals used in daily practice, with inhibitory activity on voltage gated sodium channels. For every drug found, the literature was reviewed in order to define if it may act against cancer cells as an anti-invasion and anti-metastatic agent and if it was tested with this purpose in the experimental and clinical settings. Results: The following pharmaceuticals that fulfill the above mentioned effects, were found: phenytoin, carbamazepine, valproate, lamotrigine, ranolazine, resveratrol, ropivacaine, lidocaine, mexiletine, flunarizine, and riluzole. Each of them are independently described and analyzed. Conclusions: The above mentioned pharmaceuticals have shown anti-metastatic and anti-invasion activity and many of them deserve to be tested in well-planned clinical trials as adjunct therapies for solid tumors and as anti-metastatic agents. Antiepileptic drugs like phenytoin, carbamazepine and valproate and the vasodilator flunarizine emerged as particularly useful for anti-metastatic purposes.
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Affiliation(s)
- Tomas Koltai
- Centro de Diagnóstico y Tratamiento de la Obra Social del Personal de la Industria de la Alimentación, Talar, Buenos Aires, C1122AAL, Argentina
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Ho N, Gendron RL, Grozinger K, Whelan MA, Hicks EA, Tennakoon B, Gardiner D, Good WV, Paradis H. Tubedown regulation of retinal endothelial permeability signaling pathways. Biol Open 2015; 4:970-9. [PMID: 26142315 PMCID: PMC4542279 DOI: 10.1242/bio.010496] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Tubedown (Tbdn; Naa15), a subunit of the N-terminal acetyltransferase NatA, complexes with the c-Src substrate Cortactin and supports adult retinal homeostasis through regulation of vascular permeability. Here we investigate the role of Tbdn expression on signaling components of retinal endothelial permeability to understand how Tbdn regulates the vasculature and supports retinal homeostasis. Tbdn knockdown-induced hyperpermeability to Albumin in retinal endothelial cells was associated with an increase in the levels of activation of the Src family kinases (SFK) c-Src, Fyn and Lyn and phospho-Cortactin (Tyr421). The knockdown of Cortactin expression reduced Tbdn knockdown-induced permeability to Albumin and the levels of activated SFK. Inhibition of SFK in retinal endothelial cells decreased Tbdn knockdown-induced permeability to Albumin and phospho-Cortactin (Tyr421) levels. Retinal lesions of endothelial-specific Tbdn knockdown mice, with tissue thickening, fibrovascular growth, and hyperpermeable vessels displayed an increase in the levels of activated c-Src. Moreover, the retinal lesions of patients with proliferative diabetic retinopathy (PDR) associated with a loss of Tbdn expression and hyperpermeability to Albumin displayed increased levels of activated SFK in retinal blood vessels. Taken together, these results implicate Tbdn as an important regulator of retinal endothelial permeability and homeostasis by modulating a signaling pathway involving c-Src and Cortactin.
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Affiliation(s)
- Nhu Ho
- Division of BioMedical Sciences, Department of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada A1B 3V6
| | - Robert L Gendron
- Division of BioMedical Sciences, Department of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada A1B 3V6
| | - Kindra Grozinger
- Division of BioMedical Sciences, Department of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada A1B 3V6
| | - Maria A Whelan
- Division of BioMedical Sciences, Department of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada A1B 3V6
| | - Emily Anne Hicks
- Division of BioMedical Sciences, Department of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada A1B 3V6
| | - Bimal Tennakoon
- Division of BioMedical Sciences, Department of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada A1B 3V6
| | - Danielle Gardiner
- Division of BioMedical Sciences, Department of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada A1B 3V6
| | - William V Good
- Smith-Kettlewell Eye Research Institute, San Francisco, CA 94115, USA
| | - Hélène Paradis
- Division of BioMedical Sciences, Department of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada A1B 3V6
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Hippocampal Cortactin Levels are Reduced Following Spatial Working Memory Formation, an Effect Blocked by Chronic Calpain Inhibition. Brain Sci 2015; 5:241-57. [PMID: 26103422 PMCID: PMC4493467 DOI: 10.3390/brainsci5020241] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 05/12/2015] [Accepted: 06/12/2015] [Indexed: 12/19/2022] Open
Abstract
The mechanism by which the hippocampus facilitates declarative memory formation appears to involve, among other things, restructuring of the actin cytoskeleton within neuronal dendrites. One protein involved in this process is cortactin, which is an important link between extracellular signaling and cytoskeletal reorganization. In this paper, we demonstrate that total hippocampal cortactin, as well as Y421-phosphorylated cortactin are transiently reduced following spatial working memory formation in the radial arm maze (RAM). Because cortactin is a substrate of the cysteine protease calpain, we also assessed the effect of chronic calpain inhibition on RAM performance and cortactin expression. Calpain inhibition impaired spatial working memory and blocked the reduction in hippocampal cortactin levels following RAM training. These findings add to a growing body of research implicating cortactin and calpain in hippocampus-dependent memory formation.
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Passaro D, Irigoyen M, Catherinet C, Gachet S, Da Costa De Jesus C, Lasgi C, Tran Quang C, Ghysdael J. CXCR4 Is Required for Leukemia-Initiating Cell Activity in T Cell Acute Lymphoblastic Leukemia. Cancer Cell 2015; 27:769-79. [PMID: 26058076 DOI: 10.1016/j.ccell.2015.05.003] [Citation(s) in RCA: 129] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 04/05/2015] [Accepted: 05/07/2015] [Indexed: 12/21/2022]
Abstract
Impaired cell migration has been demonstrated in T cell acute lymphoblastic leukemia (T-ALL) cells upon calcineurin inactivation, among other phenotypic traits including increased apoptosis, inhibition of cell proliferation, and ultimately inhibition of leukemia-initiating cell (LIC) activity. Herein we demonstrate that the chemokine receptor CXCR4 is essential to the LIC activity of T-ALL leukemic cells both in NOTCH-induced mouse T-ALL and human T-ALL xenograft models. We further demonstrate that calcineurin regulates CXCR4 cell-surface expression in a cortactin-dependent manner, a mechanism essential to the migratory properties of T-ALL cells. Because 20%-25% of pediatric and over 50% of adult patients with T-ALL do not achieve complete remission and relapse, our results call for clinical trials incorporating CXCR4 antagonists in T-ALL treatment.
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Affiliation(s)
- Diana Passaro
- Institut Curie, Centre Universitaire, Bat 110, 91405 Orsay, France; Centre National de la Recherche Scientifique, Unité Mixte de Recherche 3306, Centre Universitaire, Bat 110, 91405 Orsay, France; Institut National de la Santé et de la Recherche Médicale, Unité 1005, Centre Universitaire, Bat 110, 91405 Orsay, France.
| | - Marta Irigoyen
- Institut Curie, Centre Universitaire, Bat 110, 91405 Orsay, France; Centre National de la Recherche Scientifique, Unité Mixte de Recherche 3306, Centre Universitaire, Bat 110, 91405 Orsay, France; Institut National de la Santé et de la Recherche Médicale, Unité 1005, Centre Universitaire, Bat 110, 91405 Orsay, France
| | - Claire Catherinet
- Institut Curie, Centre Universitaire, Bat 110, 91405 Orsay, France; Centre National de la Recherche Scientifique, Unité Mixte de Recherche 3306, Centre Universitaire, Bat 110, 91405 Orsay, France; Institut National de la Santé et de la Recherche Médicale, Unité 1005, Centre Universitaire, Bat 110, 91405 Orsay, France
| | - Stéphanie Gachet
- Institut Curie, Centre Universitaire, Bat 110, 91405 Orsay, France; Centre National de la Recherche Scientifique, Unité Mixte de Recherche 3306, Centre Universitaire, Bat 110, 91405 Orsay, France; Institut National de la Santé et de la Recherche Médicale, Unité 1005, Centre Universitaire, Bat 110, 91405 Orsay, France
| | - Cindy Da Costa De Jesus
- Institut Curie, Centre Universitaire, Bat 110, 91405 Orsay, France; Centre National de la Recherche Scientifique, Unité Mixte de Recherche 3306, Centre Universitaire, Bat 110, 91405 Orsay, France; Institut National de la Santé et de la Recherche Médicale, Unité 1005, Centre Universitaire, Bat 110, 91405 Orsay, France
| | - Charlène Lasgi
- Institut Curie, Centre Universitaire, Bat 110, 91405 Orsay, France; Centre National de la Recherche Scientifique, Unité Mixte de Recherche 3306, Centre Universitaire, Bat 110, 91405 Orsay, France; Institut National de la Santé et de la Recherche Médicale, Unité 1005, Centre Universitaire, Bat 110, 91405 Orsay, France
| | - Christine Tran Quang
- Institut Curie, Centre Universitaire, Bat 110, 91405 Orsay, France; Centre National de la Recherche Scientifique, Unité Mixte de Recherche 3306, Centre Universitaire, Bat 110, 91405 Orsay, France; Institut National de la Santé et de la Recherche Médicale, Unité 1005, Centre Universitaire, Bat 110, 91405 Orsay, France
| | - Jacques Ghysdael
- Institut Curie, Centre Universitaire, Bat 110, 91405 Orsay, France; Centre National de la Recherche Scientifique, Unité Mixte de Recherche 3306, Centre Universitaire, Bat 110, 91405 Orsay, France; Institut National de la Santé et de la Recherche Médicale, Unité 1005, Centre Universitaire, Bat 110, 91405 Orsay, France.
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Hanniford D, Segura MF, Zhong J, Philips E, Jirau-Serrano X, Darvishian F, Berman RS, Shapiro RL, Pavlick AC, Brown B, Osman I, Hernando E. Identification of metastasis-suppressive microRNAs in primary melanoma. J Natl Cancer Inst 2015; 107:dju494. [PMID: 25677173 DOI: 10.1093/jnci/dju494] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Surgical management of primary melanoma is curative for most patients with clinically localized disease at diagnosis; however, a substantial number of patients recur and progress to advanced disease. Understanding molecular alterations that influence differential tumor progression of histopathologically similar lesions may lead to improved prognosis and therapies to slow or prevent metastasis. METHODS We examined microRNA dysregulation by expression profiling of primary melanoma tumors from 92 patients. We screened candidate microRNAs selected by differential expression between recurrent and nonrecurrent tumors or associated with primary tumor thickness (Student's t test, Benjamini-Hochberg False Discovery Rate [FDR] < 0.05), in in vitro invasion assays. We performed in vivo metastasis assays, matrix remodeling experiments, and molecular studies to identify metastasis-regulating microRNAs and their cellular and molecular mechanisms. All statistical tests were two-sided. RESULTS We identified two microRNAs (hsa-miR-382, hsa-miR-516b) whose expression was lower in aggressive vs nonaggressive primary tumors, which suppressed invasion in vitro and metastasis in vivo (mean metastatic foci: control: 37.9, 95% confidence interval [CI] = 25.6 to 50.2; miR-382: 19.5, 95% CI = 12.2 to 26.9, P = .009; miR-516b: 12.5, 95% CI = 7.7 to 17.4, P < .001, Student's t test). Mechanistically, miR-382 overexpression inhibits extracellular matrix degradation by melanoma cells. Moreover, we identified actin regulators CTTN, RAC1, and ARPC2 as direct targets of miR-382. Depletion of CTTN partially recapitulates miR-382 effects on matrix remodeling, invasion, and metastasis. Inhibition of miR-382 in a weakly tumorigenic melanoma cell line increased tumor progression and metastasis in vivo. CONCLUSIONS Aberrant expression of specific microRNAs that can functionally impact progression of primary melanoma occurs as an early event of melanomagenesis.
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Affiliation(s)
- Doug Hanniford
- Department of Pathology (DH, MFS, EP, XJS, FD, EH), Interdisciplinary Melanoma Cooperative Group (DH, MFS, JZ, XJS, FD, RSB, RLS, AP, IO, EH), Department of Environmental Medicine (JZ), Department of Dermatology (AP, IO), Department of Medicine (AP, IO), Department of Urology (IO); Department of Surgery (RSB, RLS), NYU Langone Medical Center, New York, NY; Genetics and Genomics Sciences, Icahn School of Medicine at Mount Sinai, New York, NY (BB)
| | - Miguel F Segura
- Department of Pathology (DH, MFS, EP, XJS, FD, EH), Interdisciplinary Melanoma Cooperative Group (DH, MFS, JZ, XJS, FD, RSB, RLS, AP, IO, EH), Department of Environmental Medicine (JZ), Department of Dermatology (AP, IO), Department of Medicine (AP, IO), Department of Urology (IO); Department of Surgery (RSB, RLS), NYU Langone Medical Center, New York, NY; Genetics and Genomics Sciences, Icahn School of Medicine at Mount Sinai, New York, NY (BB)
| | - Judy Zhong
- Department of Pathology (DH, MFS, EP, XJS, FD, EH), Interdisciplinary Melanoma Cooperative Group (DH, MFS, JZ, XJS, FD, RSB, RLS, AP, IO, EH), Department of Environmental Medicine (JZ), Department of Dermatology (AP, IO), Department of Medicine (AP, IO), Department of Urology (IO); Department of Surgery (RSB, RLS), NYU Langone Medical Center, New York, NY; Genetics and Genomics Sciences, Icahn School of Medicine at Mount Sinai, New York, NY (BB)
| | - Elliot Philips
- Department of Pathology (DH, MFS, EP, XJS, FD, EH), Interdisciplinary Melanoma Cooperative Group (DH, MFS, JZ, XJS, FD, RSB, RLS, AP, IO, EH), Department of Environmental Medicine (JZ), Department of Dermatology (AP, IO), Department of Medicine (AP, IO), Department of Urology (IO); Department of Surgery (RSB, RLS), NYU Langone Medical Center, New York, NY; Genetics and Genomics Sciences, Icahn School of Medicine at Mount Sinai, New York, NY (BB)
| | - Xavier Jirau-Serrano
- Department of Pathology (DH, MFS, EP, XJS, FD, EH), Interdisciplinary Melanoma Cooperative Group (DH, MFS, JZ, XJS, FD, RSB, RLS, AP, IO, EH), Department of Environmental Medicine (JZ), Department of Dermatology (AP, IO), Department of Medicine (AP, IO), Department of Urology (IO); Department of Surgery (RSB, RLS), NYU Langone Medical Center, New York, NY; Genetics and Genomics Sciences, Icahn School of Medicine at Mount Sinai, New York, NY (BB)
| | - Farbod Darvishian
- Department of Pathology (DH, MFS, EP, XJS, FD, EH), Interdisciplinary Melanoma Cooperative Group (DH, MFS, JZ, XJS, FD, RSB, RLS, AP, IO, EH), Department of Environmental Medicine (JZ), Department of Dermatology (AP, IO), Department of Medicine (AP, IO), Department of Urology (IO); Department of Surgery (RSB, RLS), NYU Langone Medical Center, New York, NY; Genetics and Genomics Sciences, Icahn School of Medicine at Mount Sinai, New York, NY (BB)
| | - Russell S Berman
- Department of Pathology (DH, MFS, EP, XJS, FD, EH), Interdisciplinary Melanoma Cooperative Group (DH, MFS, JZ, XJS, FD, RSB, RLS, AP, IO, EH), Department of Environmental Medicine (JZ), Department of Dermatology (AP, IO), Department of Medicine (AP, IO), Department of Urology (IO); Department of Surgery (RSB, RLS), NYU Langone Medical Center, New York, NY; Genetics and Genomics Sciences, Icahn School of Medicine at Mount Sinai, New York, NY (BB)
| | - Richard L Shapiro
- Department of Pathology (DH, MFS, EP, XJS, FD, EH), Interdisciplinary Melanoma Cooperative Group (DH, MFS, JZ, XJS, FD, RSB, RLS, AP, IO, EH), Department of Environmental Medicine (JZ), Department of Dermatology (AP, IO), Department of Medicine (AP, IO), Department of Urology (IO); Department of Surgery (RSB, RLS), NYU Langone Medical Center, New York, NY; Genetics and Genomics Sciences, Icahn School of Medicine at Mount Sinai, New York, NY (BB)
| | - Anna C Pavlick
- Department of Pathology (DH, MFS, EP, XJS, FD, EH), Interdisciplinary Melanoma Cooperative Group (DH, MFS, JZ, XJS, FD, RSB, RLS, AP, IO, EH), Department of Environmental Medicine (JZ), Department of Dermatology (AP, IO), Department of Medicine (AP, IO), Department of Urology (IO); Department of Surgery (RSB, RLS), NYU Langone Medical Center, New York, NY; Genetics and Genomics Sciences, Icahn School of Medicine at Mount Sinai, New York, NY (BB)
| | - Brian Brown
- Department of Pathology (DH, MFS, EP, XJS, FD, EH), Interdisciplinary Melanoma Cooperative Group (DH, MFS, JZ, XJS, FD, RSB, RLS, AP, IO, EH), Department of Environmental Medicine (JZ), Department of Dermatology (AP, IO), Department of Medicine (AP, IO), Department of Urology (IO); Department of Surgery (RSB, RLS), NYU Langone Medical Center, New York, NY; Genetics and Genomics Sciences, Icahn School of Medicine at Mount Sinai, New York, NY (BB)
| | - Iman Osman
- Department of Pathology (DH, MFS, EP, XJS, FD, EH), Interdisciplinary Melanoma Cooperative Group (DH, MFS, JZ, XJS, FD, RSB, RLS, AP, IO, EH), Department of Environmental Medicine (JZ), Department of Dermatology (AP, IO), Department of Medicine (AP, IO), Department of Urology (IO); Department of Surgery (RSB, RLS), NYU Langone Medical Center, New York, NY; Genetics and Genomics Sciences, Icahn School of Medicine at Mount Sinai, New York, NY (BB)
| | - Eva Hernando
- Department of Pathology (DH, MFS, EP, XJS, FD, EH), Interdisciplinary Melanoma Cooperative Group (DH, MFS, JZ, XJS, FD, RSB, RLS, AP, IO, EH), Department of Environmental Medicine (JZ), Department of Dermatology (AP, IO), Department of Medicine (AP, IO), Department of Urology (IO); Department of Surgery (RSB, RLS), NYU Langone Medical Center, New York, NY; Genetics and Genomics Sciences, Icahn School of Medicine at Mount Sinai, New York, NY (BB).
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Mimae T, Ito A. New challenges in pseudopodial proteomics by a laser-assisted cell etching technique. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1854:538-46. [PMID: 25461796 DOI: 10.1016/j.bbapap.2014.10.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 09/10/2014] [Accepted: 10/10/2014] [Indexed: 12/26/2022]
Abstract
Pseudopodia are ventral membrane protrusions that extend toward higher concentrations of chemoattractants and play key roles in cell migration and cancer cell invasion. Cancers, including carcinoma and sarcoma, become life threatening when they invade surrounding structures and other organs. Understanding the molecular basis of invasiveness is important for the elimination of cancers. Thus, determining the pseudopodial composition will offer insights into the mechanisms underlying tumor cell invasiveness and provide potential biomarkers and therapeutic targets. Pseudopodial composition has been extensively investigated by using proteomic approaches. A variety of modalities, including gel-based and mass spectrometry-based methods, have been employed for pseudopodial proteomics. Our research group recently established a novel method using excimer laser pulses to selectively harvest pseudopodia, and we successfully identified a number of new pseudopodial constituents. Here, we summarized the conventional proteomic procedures and describe our new excimer laser-assisted method, with a special emphasis on the differences in the methods used to isolate pseudopodia. In addition, we discussed the theoretical background for the use of excimer laser-mediated cell ablation in proteomic applications. Using the excimer laser-assisted method, we showed that alpha-parvin, an actin-binding adaptor protein, is localized to pseudopodia, and is involved in breast cancer invasiveness. Our results clearly indicate that excimer laser-assisted cell etching is a useful technique for pseudopodial proteomics. This article is part of a Special Issue entitled: Medical Proteomics.
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Affiliation(s)
- Takahiro Mimae
- Department of Surgical Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima 734-8551, Japan.
| | - Akihiko Ito
- Department of Pathology, Faculty of Medicine, Kinki University, Osaka 589-8511, Japan
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Chen S, Tang DD. c-Abl tyrosine kinase regulates cytokinesis of human airway smooth muscle cells. Am J Respir Cell Mol Biol 2014; 50:1076-83. [PMID: 24392933 DOI: 10.1165/rcmb.2013-0438oc] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Cytokinesis is a critical step of airway smooth muscle cell division that plays an essential role in the development and homeostasis of the respiratory system, as well as the progression of airway remodeling. The mechanisms that regulate smooth muscle cytokinesis are not fully understood. c-Abl (c-Abelson tyrosine kinase) is a nonreceptor protein tyrosine kinase that has a role in regulating actin dynamics and smooth muscle contraction. The role of c-Abl in cytokinesis has not been investigated. Here, c-Abl was found in the contractile ring, as evidenced by immunofluorescent microscopy. In addition, cortactin is a phosphorylatable protein that has been implicated in actin filament assembly. In this report, phosphorylated cortactin was also found in the contractile ring. Knockdown of c-Abl by RNA interference attenuated cortactin phosphorylation in the midzone and contractile ring formation. c-Abl knockdown decreased the number of cells undergoing cytokinesis, but increased the quantity of cells in metaphase/anaphase and the number of multinucleate cells. Treatment with the c-Abl pharmacological inhibitors, imatinib and GNF-5, had similar effects. Furthermore, the expression of a nonphosphorylatable cortactin mutant diminished cytokinesis. Finally, inhibition of actin filament assembly by latrunculin A attenuated c-Abl recruitment to the midzone. Thus, we propose a novel mechanism that regulates smooth muscle cell cytokinesis. c-Abl is recruited to the equator during cytokinesis, which may mediate cortactin phosphorylation. Phosphorylated cortactin may promote actin filament assembly, which facilitates contractile ring formation and cytokinesis. In addition, actin filament polymerization may facilitate the positioning of c-Abl to the contractile ring.
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Affiliation(s)
- Shu Chen
- Center for Cardiovascular Sciences, Albany Medical College, Albany, New York
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Belvitch P, Adyshev D, Elangovan VR, Brown ME, Naureckas C, Rizzo AN, Siegler JH, Garcia JGN, Dudek SM. Proline-rich region of non-muscle myosin light chain kinase modulates kinase activity and endothelial cytoskeletal dynamics. Microvasc Res 2014; 95:94-102. [PMID: 25072537 DOI: 10.1016/j.mvr.2014.07.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 07/01/2014] [Accepted: 07/17/2014] [Indexed: 01/11/2023]
Abstract
Disruption of the pulmonary endothelial barrier and subsequent vascular leak is a hallmark of acute lung injury. Dynamic rearrangements in the endothelial cell (EC) peripheral membrane and underlying cytoskeleton are critical determinants of barrier function. The cytoskeletal effector protein non-muscle myosin light chain kinase (nmMLCK) and the actin-binding regulatory protein cortactin are important regulators of the endothelial barrier. In the present study we functionally characterize a proline-rich region of nmMLCK previously identified as the possible site of interaction between nmMLCK and cortactin. A mutant nmMLCK construct deficient in proline residues at the putative sites of cortactin binding (amino acids 973, 976, 1019, 1022) was generated. Co-immunoprecipitation studies in human lung EC transfected with wild-type or mutant nmMLCK demonstrated similar levels of cortactin interaction at baseline and after stimulation with the barrier-enhancing agonist, sphingosine 1-phosphate (S1P). In contrast, binding studies utilizing recombinant nmMLCK fragments containing the wild-type or proline-deficient sequence demonstrated a two-fold increase in cortactin binding (p<0.01) to the mutant construct. Immunofluorescent microscopy revealed an increased stress fiber density in ECs expressing GFP-labeled mutant nmMLCK at baseline (p=0.02) and after thrombin (p=0.01) or S1P (p=0.02) when compared to wild-type. Mutant nmMLCK demonstrated an increase in kinase activity in response to thrombin (p<0.01). Kymographic analysis demonstrated an increased EC membrane retraction distance and velocity (p<0.01) in response to the barrier disrupting agent thrombin in cells expressing the mutant vs. the wild-type nmMLCK construct. These results provide evidence that critical prolines within nmMLCK (amino acids 973, 976, 1019, 1022) regulate cytoskeletal and membrane events associated with pulmonary endothelial barrier function.
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Affiliation(s)
- Patrick Belvitch
- Division of Pulmonary, Critical Care, Sleep, and Allergy, University of Illinois Hospital and Health Science System, Chicago, IL, USA
| | - Djanybek Adyshev
- Division of Pulmonary, Critical Care, Sleep, and Allergy, University of Illinois Hospital and Health Science System, Chicago, IL, USA
| | - Venkateswaran R Elangovan
- Division of Pulmonary, Critical Care, Sleep, and Allergy, University of Illinois Hospital and Health Science System, Chicago, IL, USA
| | - Mary E Brown
- Division of Pulmonary, Critical Care, Sleep, and Allergy, University of Illinois Hospital and Health Science System, Chicago, IL, USA
| | - Caitlin Naureckas
- Division of Pulmonary, Critical Care, Sleep, and Allergy, University of Illinois Hospital and Health Science System, Chicago, IL, USA
| | - Alicia N Rizzo
- Division of Pulmonary, Critical Care, Sleep, and Allergy, University of Illinois Hospital and Health Science System, Chicago, IL, USA
| | - Jessica H Siegler
- Division of Pulmonary, Critical Care, Sleep, and Allergy, University of Illinois Hospital and Health Science System, Chicago, IL, USA
| | - Joe G N Garcia
- University of Arizona Health Sciences Center, Tucson, AZ, USA
| | - Steven M Dudek
- Division of Pulmonary, Critical Care, Sleep, and Allergy, University of Illinois Hospital and Health Science System, Chicago, IL, USA.
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Li J, Chen S, Cleary RA, Wang R, Gannon OJ, Seto E, Tang DD. Histone deacetylase 8 regulates cortactin deacetylation and contraction in smooth muscle tissues. Am J Physiol Cell Physiol 2014; 307:C288-95. [PMID: 24920679 DOI: 10.1152/ajpcell.00102.2014] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Histone deacetylases (HDACs) are a family of enzymes that mediate nucleosomal histone deacetylation and gene expression. Some members of the HDAC family have also been implicated in nonhistone protein deacetylation, which modulates cell-cycle control, differentiation, and cell migration. However, the role of HDACs in smooth muscle contraction is largely unknown. Here, HDAC8 was localized both in the cytoplasm and the nucleus of mouse and human smooth muscle cells. Knockdown of HDAC8 by lentivirus-encoding HDAC8 shRNA inhibited force development in response to acetylcholine. Treatment of smooth muscle tissues with HDAC8 inhibitor XXIV (OSU-HDAC-44) induced relaxation of precontracted smooth muscle tissues. In addition, cortactin is an actin-regulatory protein that undergoes deacetylation during migration of NIH 3T3 cells. In this study, acetylcholine stimulation induced cortactin deacetylation in mouse and human smooth muscle tissues, as evidenced by immunoblot analysis using antibody against acetylated lysine. Knockdown of HDAC8 by RNAi or treatment with the inhibitor attenuated cortactin deacetylation and actin polymerization without affecting myosin activation. Furthermore, expression of a charge-neutralizing cortactin mutant inhibited contraction and actin dynamics during contractile activation. These results suggest a novel mechanism for the regulation of smooth muscle contraction. In response to contractile stimulation, HDAC8 may mediate cortactin deacetylation, which subsequently promotes actin filament polymerization and smooth muscle contraction.
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Affiliation(s)
- Jia Li
- Center for Cardiovascular Sciences, Albany Medical College, Albany, New York; and
| | - Shu Chen
- Center for Cardiovascular Sciences, Albany Medical College, Albany, New York; and
| | - Rachel A Cleary
- Center for Cardiovascular Sciences, Albany Medical College, Albany, New York; and
| | - Ruping Wang
- Center for Cardiovascular Sciences, Albany Medical College, Albany, New York; and
| | - Olivia J Gannon
- Center for Cardiovascular Sciences, Albany Medical College, Albany, New York; and
| | - Edward Seto
- Molecular Oncology Department, Moffitt Cancer Center, Tampa, Florida
| | - Dale D Tang
- Center for Cardiovascular Sciences, Albany Medical College, Albany, New York; and
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Wang R, Cleary RA, Wang T, Li J, Tang DD. The association of cortactin with profilin-1 is critical for smooth muscle contraction. J Biol Chem 2014; 289:14157-69. [PMID: 24700464 DOI: 10.1074/jbc.m114.548099] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Profilin-1 (Pfn-1) is an actin-regulatory protein that has a role in modulating smooth muscle contraction. However, the mechanisms that regulate Pfn-1 in smooth muscle are not fully understood. Here, stimulation with acetylcholine induced an increase in the association of the adapter protein cortactin with Pfn-1 in smooth muscle cells/tissues. Furthermore, disruption of the protein/protein interaction by a cell-permeable peptide (CTTN-I peptide) attenuated actin polymerization and smooth muscle contraction without affecting myosin light chain phosphorylation at Ser-19. Knockdown of cortactin by lentivirus-mediated RNAi also diminished actin polymerization and smooth muscle force development. However, cortactin knockdown did not affect myosin activation. In addition, cortactin phosphorylation has been implicated in nonmuscle cell migration. In this study, acetylcholine stimulation induced cortactin phosphorylation at Tyr-421 in smooth muscle cells. Phenylalanine substitution at this position impaired cortactin/Pfn-1 interaction in response to contractile activation. c-Abl is a tyrosine kinase that is necessary for actin dynamics and contraction in smooth muscle. Here, c-Abl silencing inhibited the agonist-induced cortactin phosphorylation and the association of cortactin with Pfn-1. Finally, treatment with CTTN-I peptide reduced airway resistance and smooth muscle hyperreactivity in a murine model of asthma. These results suggest that the interaction of cortactin with Pfn-1 plays a pivotal role in regulating actin dynamics, smooth muscle contraction, and airway hyperresponsiveness in asthma. The association of cortactin with Pfn-1 is regulated by c-Abl-mediated cortactin phosphorylation.
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Affiliation(s)
- Ruping Wang
- From the Center for Cardiovascular Sciences, Albany Medical College, Albany, New York 12208
| | - Rachel A Cleary
- From the Center for Cardiovascular Sciences, Albany Medical College, Albany, New York 12208
| | - Tao Wang
- From the Center for Cardiovascular Sciences, Albany Medical College, Albany, New York 12208
| | - Jia Li
- From the Center for Cardiovascular Sciences, Albany Medical College, Albany, New York 12208
| | - Dale D Tang
- From the Center for Cardiovascular Sciences, Albany Medical College, Albany, New York 12208
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Lu P, Qiao J, He W, Wang J, Jia Y, Sun Y, Tang S, Fu L, Qin Y. Genome-wide gene expression profile analyses identify CTTN as a potential prognostic marker in esophageal cancer. PLoS One 2014; 9:e88918. [PMID: 24551190 PMCID: PMC3925182 DOI: 10.1371/journal.pone.0088918] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 01/16/2014] [Indexed: 12/29/2022] Open
Abstract
Aim Esophageal squamous cell carcinoma (ESCC) is one of the most common fatal malignances of the digestive tract. Its prognosis is poor mainly due to the lack of reliable markers for early detection and prognostic prediction. Here we aim to identify the molecules involved in ESCC carcinogenesis and those as potential markers for prognosis and as new molecular therapeutic targets. Methods We performed genome-wide gene expression profile analyses of 10 primary ESCCs and their adjacent normal tissues by cDNA microarrays representing 47,000 transcripts and variants. Candidate genes were then validated by semi quantitative reverse transcription-PCR (RT-PCR), tissue microarrays (TMAs) and immunohistochemistry (IHC) staining. Results Using an arbitrary cutoff line of signal log ratio of ≥1.5 or ≤−1.5, we observed 549 up-regulated genes and 766 down-regulated genes in ESCCs compared with normal esophageal tissues. The functions of 302 differentially expressed genes were associated with cell metabolism, cell adhesion and immune response. Several candidate deregulated genes including four overexpressed (CTTN, DMRT2, MCM10 and SCYA26) and two underexpressed (HMGCS2 and SORBS2) were subsequently verified, which can be served as biomarkers for ESCC. Moreover, overexpression of cortactin (CTTN) was observed in 126/198 (63.6%) of ESCC cases and was significantly associated with lymph node metastasis (P = 0.000), pathologic stage (P = 0.000) and poor survival (P<0.001) of ESCC patients. Furthermore, a significant correlation between CTTN overexpression and shorter disease-specific survival rate was found in different subgroups of ESCC patient stratified by the pathologic stage (P<0.05). Conclusion Our data provide valuable information for establishing molecules as candidates for prognostic and/or as therapeutic targets.
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Affiliation(s)
- Pei Lu
- Department of Clinical Oncology, the First Affiliated Hospital, Zhengzhou University, Zhengzhou, China
| | - Junjing Qiao
- Department of Clinical Oncology, the First Affiliated Hospital, Zhengzhou University, Zhengzhou, China
| | - Wei He
- Department of Clinical Oncology, the First Affiliated Hospital, Zhengzhou University, Zhengzhou, China
| | - Jin Wang
- Department of Clinical Oncology, the First Affiliated Hospital, Zhengzhou University, Zhengzhou, China
| | - Yongxu Jia
- Department of Clinical Oncology, the First Affiliated Hospital, Zhengzhou University, Zhengzhou, China
| | - Yan Sun
- Department of Clinical Oncology, the First Affiliated Hospital, Zhengzhou University, Zhengzhou, China
| | - Senwei Tang
- Department of Medicine and Therapeutics, the Chinese University of Hong Kong, Hong Kong, China
| | - Li Fu
- Department of Medicine and Therapeutics, the Chinese University of Hong Kong, Hong Kong, China
| | - Yanru Qin
- Department of Clinical Oncology, the First Affiliated Hospital, Zhengzhou University, Zhengzhou, China
- * E-mail:
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Navratil AM, Dozier MG, Whitesell JD, Clay CM, Roberson MS. Role of cortactin in dynamic actin remodeling events in gonadotrope cells. Endocrinology 2014; 155:548-57. [PMID: 24274984 PMCID: PMC3891938 DOI: 10.1210/en.2012-1924] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
GnRH induces marked activation of the actin cytoskeleton in gonadotropes; however, the physiological consequences and cellular mechanisms responsible have yet to be fully elucidated. The current studies focus on the actin scaffolding protein cortactin. Using the gonadotrope-derived αT3-1 cell line, we found that cortactin is phosphorylated at Y(421), S(405), and S(418) in a time-dependent manner in response to the GnRH agonist buserelin (GnRHa). GnRHa induced translocation of cortactin to the leading edge of the plasma membrane where it colocalizes with actin and actin-related protein 3 (Arp3). Incubation of αT3-1 cells with the c-src inhibitor phosphoprotein phosphatase 1, blocked tyrosine phosphorylation of cortactin, reduced cortactin association with Arp3, and blunted actin reorganization in response to GnRHa. Additionally, we used RNA silencing strategies to knock down cortactin in αT3-1 cells. Knockdown of cortactin blocked the ability of αT3-1 cells to generate filopodia, lamellipodia, and membrane ruffles in response to GnRHa. We show that lamellipodia and filopodia are capable of LHβ mobilization in primary pituitary culture after GnRHa treatment, and disruption of these structures using jasplakinolide reduces LH secretion. Collectively, our findings suggest that after GnRHa activation, src activity leads to tyrosine phosphorylation of cortactin, which facilitates its association with Arp3 to engage the actin cytoskeleton. The reorganization of actin by cortactin potentially underlies GnRHa-induced secretory events within αT3-1 cells.
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Affiliation(s)
- Amy M Navratil
- College of Arts and Sciences, Department of Zoology and Physiology (A.M.N., M.G.D.), University of Wyoming, Laramie, Wyoming 82071; College of Veterinary Medicine and Biomedical Science, Departments of Microbiology, Immunology, and Pathology (J.D.W.) and Biomedical Sciences (C.M.C.), Colorado State University, Ft Collins, Colorado, 80523; and College of Veterinary Medicine, Department of Biomedical Sciences (M.S.R.), Cornell University, Ithaca, New York 14853
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The inhibition of migration and invasion of cancer cells by graphene via the impairment of mitochondrial respiration. Biomaterials 2014; 35:1597-607. [DOI: 10.1016/j.biomaterials.2013.11.020] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 11/07/2013] [Indexed: 11/20/2022]
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Cleary RA, Wang R, Waqar O, Singer HA, Tang DD. Role of c-Abl tyrosine kinase in smooth muscle cell migration. Am J Physiol Cell Physiol 2014; 306:C753-61. [PMID: 24477238 DOI: 10.1152/ajpcell.00327.2013] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
c-Abl is a nonreceptor protein tyrosine kinase that has a role in regulating smooth muscle cell proliferation and contraction. The role of c-Abl in smooth muscle cell migration has not been investigated. In the present study, c-Abl was found in the leading edge of smooth muscle cells. Knockdown of c-Abl by RNA interference attenuated smooth muscle cell motility as evidenced by time-lapse microscopy. Furthermore, the actin-associated proteins cortactin and profilin-1 (Pfn-1) have been implicated in cell migration. In this study, cell adhesion induced cortactin phosphorylation at Tyr-421, an indication of cortactin activation. Phospho-cortactin and Pfn-1 were also found in the cell edge. Pfn-1 directly interacted with cortactin in vitro. Silencing of c-Abl attenuated adhesion-induced cortactin phosphorylation and Pfn-1 localization in the cell edge. To assess the role of cortactin/Pfn-1 coupling, we developed a cell-permeable peptide. Treatment with the peptide inhibited the interaction of cortactin with Pfn-1 without affecting cortactin phosphorylation. Moreover, treatment with the peptide impaired the recruitment of Pfn-1 to the leading edge and cell migration. Finally, β1-integrin was required for the recruitment of c-Abl to the cell edge. Inhibition of actin dynamics impaired the spatial distribution of c-Abl. These results suggest that β1-integrin may recruit c-Abl to the leading cell edge, which may regulate cortactin phosphorylation in response to cell adhesion. Phosphorylated cortactin may facilitate the recruitment of Pfn-1 to the cell edge, which promotes localized actin polymerization, leading edge formation, and cell movement. Conversely, actin dynamics may strengthen the recruitment of c-Abl to the leading edge.
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Affiliation(s)
- Rachel A Cleary
- Center for Cardiovascular Sciences, Albany Medical College, Albany, New York
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Liu C, Li Q, Zhou X, Kolosov VP, Perelman JM. Cortactin mediates elevated shear stress-induced mucin hypersecretion via actin polymerization in human airway epithelial cells. Int J Biochem Cell Biol 2013; 45:2756-63. [DOI: 10.1016/j.biocel.2013.09.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 09/12/2013] [Accepted: 09/28/2013] [Indexed: 11/25/2022]
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Samuelson DR, Konkel ME. Serine phosphorylation of cortactin is required for maximal host cell invasion by Campylobacter jejuni. Cell Commun Signal 2013; 11:82. [PMID: 24188565 PMCID: PMC3832248 DOI: 10.1186/1478-811x-11-82] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 10/23/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Campylobacter jejuni causes acute disease characterized by severe diarrhea containing blood and leukocytes, fever, and abdominal cramping. Disease caused by C. jejuni is dependent on numerous bacterial and host factors. C. jejuni invasion of the intestinal epithelial cells is seen in both clinical samples and animal models indicating that host cell invasion is, in part, necessary for disease. C. jejuni utilizes a flagellar Type III Secretion System (T3SS) to deliver the Campylobacter invasion antigens (Cia) to host cells. The Cia proteins modulate host cell signaling leading to actin cytoskeleton rearrangement necessary for C. jejuni host cell invasion, and are required for the development of disease. RESULTS This study was based on the hypothesis that the C. jejuni CiaD effector protein mediates Erk 1/2 dependent cytoskeleton rearrangement. We showed that CiaD was required for the maximal phosphorylation of Erk 1/2 by performing an immunoblot with a p-Erk 1/2 specific antibody and that Erk 1/2 participates in C. jejuni invasion of host cells by performing the gentamicin protection assay in the presence and absence of the PD98059 (a potent inhibitor of Erk 1/2 activation). CiaD was also found to be required for the maximal phosphorylation of cortactin S405 and S418, as judged by immunoblot analysis. The response of human INT 407 epithelial cells to infection with C. jejuni was evaluated by confocal microscopy and scanning electron microscopy to determine the extent of membrane ruffling. This analysis revealed that CiaD, Erk 1/2, and cortactin participate in C. jejuni-induced membrane ruffling. Finally, cortactin and N-WASP were found to be involved in C. jejuni invasion of host cells using siRNA to N-WASP, and siRNA to cortactin, coupled with the gentamicin protection assay. CONCLUSION We conclude that CiaD is involved in the activation of Erk 1/2 and that activated Erk 1/2 facilitates C. jejuni invasion by phosphorylation of cortactin on serine 405 and 418. This is the first time that cortactin and N-WASP have been shown to be involved in C. jejuni invasion of host cells. These data also provide a mechanistic basis for the requirement of Erk 1/2 in C. jejuni-mediated cytoskeletal rearrangement.
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Affiliation(s)
| | - Michael E Konkel
- School of Molecular Biosciences, Washington State University, College of Veterinary Medicine, Life Sciences Bldg, Room 302c, Pullman, Washington 99164-7520, USA.
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Ma M, Baumgartner M. Filopodia and membrane blebs drive efficient matrix invasion of macrophages transformed by the intracellular parasite Theileria annulata. PLoS One 2013; 8:e75577. [PMID: 24086576 PMCID: PMC3782453 DOI: 10.1371/journal.pone.0075577] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 08/14/2013] [Indexed: 11/18/2022] Open
Abstract
Recent technical advances have broadened our understanding of processes that govern mammalian cell migration in health and disease but many of the molecular and morphological alterations that precede and accompany movement of cells - in particular in three-dimensional (3D) environments - are still incompletely understood. In this manuscript, using high-resolution and time-lapse microscopy imaging approaches, we describe morphodynamic processes during rounded/amoeboid cell invasion and molecules associated with the cellular invasion structures. We used macrophages infected with the intracellular protozoan parasite Theileria annulata, which causes Tropical Theileriosis in susceptible ruminants such as domestic cattle. T. annulata transforms its host cell that, as a result, acquires many characteristics of human cancer cells including a markedly increased potential to migrate, disseminate and expand in the body of the host animal. Hence, virulence of the disease is associated with the capability of infected cells to disseminate inside the host. Using T. annulata-transformed macrophages as a model system, we described a novel mode of rounded/amoeboid macrophage migration. We show that filopodia-like membrane extensions at the leading edge lead the way and further evolve in blebbing membrane protrusions to promote progressive expansion of the matrix. Associated with focal invasion structures we detected ezrin, radixin, moesin-family proteins and their regulatory kinase MAP4K4. Furthermore, we linked Rho-kinase activity to contractile force generation, which is essential for infected cell motility. Thus, the motility mode of these parasite-transformed macrophages contrasts with those described so far in human macrophages such as the tunneling or mesenchymal modes, which require engulfment, compaction and ingestion of matrix or proteolytic matrix degradation, respectively. Together, our data reveal protrusion dynamics at the leading edge of invading cells in 3D at unprecedented temporal and spatial resolution and suggest a novel mode of rounded/amoeboid invasive cell motility that exploits actin-driven filopodia formation in combination with pressure-driven membrane blebs.
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Affiliation(s)
- Min Ma
- Division of Neuro-Oncology, Experimental Infectious Diseases and Cancer Research, Oncology Department, University Children’s Hospital Zürich, Zürich, Switzerland
| | - Martin Baumgartner
- Division of Neuro-Oncology, Experimental Infectious Diseases and Cancer Research, Oncology Department, University Children’s Hospital Zürich, Zürich, Switzerland
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Wang S, Dong Z. Primary cilia and kidney injury: current research status and future perspectives. Am J Physiol Renal Physiol 2013; 305:F1085-98. [PMID: 23904226 DOI: 10.1152/ajprenal.00399.2013] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Cilia, membrane-enclosed organelles protruding from the apical side of cells, can be divided into two classes: motile and primary cilia. During the past decades, motile cilia have been intensively studied. However, it was not until the 1990s that people began to realize the importance of primary cilia as cellular-specific sensors, particularly in kidney tubular epithelial cells. Furthermore, accumulating evidence indicates that primary cilia may be involved in the regulation of cell proliferation, differentiation, apoptosis, and planar cell polarity. Many signaling pathways, such as Wnt, Notch, Hedgehog, and mammalian target of rapamycin, have been located to the primary cilia. Thus primary cilia have been regarded as a hub that integrates signals from the extracellular environment. More importantly, dysfunction of this organelle may contribute to the pathogenesis of a large spectrum of human genetic diseases, named ciliopathies. The significance of primary cilia in acquired human diseases such as hypertension and diabetes has gradually drawn attention. Interestingly, recent reports disclosed that cilia length varies during kidney injury, and shortening of cilia enhances the sensitivity of epithelial cells to injury cues. This review briefly summarizes the current status of cilia research and explores the potential mechanisms of cilia-length changes during kidney injury as well as provides some thoughts to allure more insightful ideas and promotes the further study of primary cilia in the context of kidney injury.
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Affiliation(s)
- Shixuan Wang
- Dept. of Cellular Biology and Anatomy, Medical College of Georgia, Augusta, GA 30912.
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Human endothelial cells internalize Candida parapsilosis via N-WASP-mediated endocytosis. Infect Immun 2013; 81:2777-87. [PMID: 23690407 DOI: 10.1128/iai.00535-13] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Candida parapsilosis is a frequent cause of disseminated candidiasis and is associated with significant morbidity and mortality. Although important in pathogenesis, interactions of this organism with endothelial cells have received less attention than those of Candida albicans. Internalization of C. parapsilosis by monolayers of human endothelial cells was examined in an in vitro assay and compared to that of C. albicans. Both live and heat-killed yeast were efficiently internalized, with heat-killed yeast subsequently being detected in an acidic subcompartment. Internalization was marked by a process of engulfment by thin membrane extensions from the endothelium. Efficiency of internalization differed among different clinical isolates and species of yeast. Opsonization of C. parapsilosis by serum factors was not sufficient to cause endocytosis; instead, serum appeared to directly stimulate endothelial uptake. Colocalization of endothelial actin and N-WASP at sites of C. parapsilosis internalization was observed. A Förster-resonance energy transfer (FRET) probe for N-WASP activity showed active N-WASP at sites of internalization for both live and heat-killed C. parapsilosis and C. albicans. An actin nucleation inhibitor (cytochalasin D) and an N-WASP inhibitor (wiskostatin) both inhibited uptake of heat-killed C. parapsilosis, as did short interfering RNA-mediated ablation of N-WASP. Thus, endocytosis by endothelial cells may represent a means of traversal of the blood vessel wall by yeast during disseminated candidiasis, and N-WASP may play a key role in the process.
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Chen K, Williams KJ. Molecular mediators for raft-dependent endocytosis of syndecan-1, a highly conserved, multifunctional receptor. J Biol Chem 2013; 288:13988-13999. [PMID: 23525115 DOI: 10.1074/jbc.m112.444737] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Endocytosis via rafts has attracted considerable recent interest, but the molecular mediators remain incompletely characterized. Here, we focused on the syndecan-1 heparan sulfate proteoglycan, a highly conserved, multifunctional receptor that we previously showed to undergo raft-dependent endocytosis upon clustering. Alanine scanning mutagenesis of three to five consecutive cytoplasmic residues at a time revealed that a conserved juxtamembrane motif, MKKK, was the only region required for efficient endocytosis after clustering. Endocytosis of clustered syndecan-1 occurs in two phases, each requiring a kinase and a corresponding cytoskeletal partner. In the initial phase, ligands trigger rapid MKKK-dependent activation of ERK and the localization of syndecan-1 into rafts. Activation of ERK drives the dissociation of syndecan-1 from α-tubulin, a molecule that may act as an anchor for syndecan-1 at the plasma membrane in the basal state. In the second phase, Src family kinases phosphorylate tyrosyl residues within the transmembrane and cytoplasmic regions of syndecan-1, a process that also requires MKKK. Tyrosine phosphorylation of syndecan-1 triggers the robust recruitment of cortactin, which we found to be an essential mediator of efficient actin-dependent endocytosis. These findings represent the first detailed characterization of the molecular events that drive endocytosis of a raft-dependent receptor and identify a novel endocytic motif, MKKK. Moreover, the results provide new tools to study syndecan function and regulation during uptake of its biologically and medically important ligands, such as HIV-1, atherogenic postprandial remnant lipoproteins, and molecules implicated in Alzheimer disease.
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Affiliation(s)
- Keyang Chen
- Division of Endocrinology, Department of Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania 19140
| | - Kevin Jon Williams
- Division of Endocrinology, Department of Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania 19140.
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Upadhyay RD, Kumar AV, Sonawane S, Gaonkar R, Balasinor NH. Estrogen Effects on Actin Cytoskeletal and Endocytic Proteins Associated With Tubulobulbar Complex Disruption in Rat Testes. Reprod Sci 2013; 20:1162-74. [DOI: 10.1177/1933719113477491] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Rahul D. Upadhyay
- Department of Neuroendocrinology, National Institute for Research in Reproductive Health, Mumbai, India
| | - Anita V. Kumar
- Department of Neuroendocrinology, National Institute for Research in Reproductive Health, Mumbai, India
| | - Shobha Sonawane
- Department of Neuroendocrinology, National Institute for Research in Reproductive Health, Mumbai, India
| | - Reshma Gaonkar
- Department of Neuroendocrinology, National Institute for Research in Reproductive Health, Mumbai, India
| | - Nafisa H. Balasinor
- Department of Neuroendocrinology, National Institute for Research in Reproductive Health, Mumbai, India
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Evans JV, Ammer AG, Jett JE, Bolcato CA, Breaux JC, Martin KH, Culp MV, Gannett PM, Weed SA. Src binds cortactin through an SH2 domain cystine-mediated linkage. J Cell Sci 2012; 125:6185-97. [PMID: 23097045 DOI: 10.1242/jcs.121046] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Tyrosine-kinase-based signal transduction mediated by modular protein domains is critical for cellular function. The Src homology (SH)2 domain is an important conductor of intracellular signaling that binds to phosphorylated tyrosines on acceptor proteins, producing molecular complexes responsible for signal relay. Cortactin is a cytoskeletal protein and tyrosine kinase substrate that regulates actin-based motility through interactions with SH2-domain-containing proteins. The Src kinase SH2 domain mediates cortactin binding and tyrosine phosphorylation, but how Src interacts with cortactin is unknown. Here we demonstrate that Src binds cortactin through cystine bonding between Src C185 in the SH2 domain within the phosphotyrosine binding pocket and cortactin C112/246 in the cortactin repeats domain, independent of tyrosine phosphorylation. Interaction studies show that the presence of reducing agents ablates Src-cortactin binding, eliminates cortactin phosphorylation by Src, and prevents Src SH2 domain binding to cortactin. Tandem MS/MS sequencing demonstrates cystine bond formation between Src C185 and cortactin C112/246. Mutational studies indicate that an intact cystine binding interface is required for Src-mediated cortactin phosphorylation, cell migration, and pre-invadopodia formation. Our results identify a novel phosphotyrosine-independent binding mode between the Src SH2 domain and cortactin. Besides Src, one quarter of all SH2 domains contain cysteines at or near the analogous Src C185 position. This provides a potential alternative mechanism to tyrosine phosphorylation for cysteine-containing SH2 domains to bind cognate ligands that may be widespread in propagating signals regulating diverse cellular functions.
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Affiliation(s)
- Jason V Evans
- Department of Neurobiology and Anatomy, Program in Cancer Cell Biology, Mary Babb Randolph Cancer Center, West Virginia University, Morgantown, WV 26506, USA
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Tanabe K, Ohashi E, Henmi Y, Takei K. Receptor sorting and actin dynamics at early endosomes. Commun Integr Biol 2012; 4:742-4. [PMID: 22446543 DOI: 10.4161/cib.17628] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The sorting machinery in early endosomes is crucial for intracellular homeostasis and signal transduction and its disruption leads to the development of various diseases. In spite of its significance, the molecular mechanism underlying this machinery remains largely unknown. Actin filaments are implicated in intracellular trafficking, including membrane fission at endocytosis, membrane stretching at the Golgi complex, and maturation of endosomes. We have recently found that actin is required for receptor sorting in early endosomes and identified cortactin as a candidate for actin regulation in early endosomes. Inhibition of actin dynamics leads to enlargement of early endosomes and impairment of the sorting; the latter is also observed in cortactin-depleted cells. The endosomal localization of cortactin was enhanced by dynasore, a dynamin inhibitor that effectively inhibits endosomal sorting, indicating that cortactin is involved in the sorting machinery in early endosomes. Here we discuss the role of actin filaments in early endosomes and other molecules implicated in endosomal trafficking.
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Affiliation(s)
- Kenji Tanabe
- Department of Neuroscience, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences; Okayama, Japan
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78
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LTP induction translocates cortactin at distant synapses in wild-type but not Fmr1 knock-out mice. J Neurosci 2012; 32:7403-13. [PMID: 22623686 DOI: 10.1523/jneurosci.0968-12.2012] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Stabilization of long-term potentiation (LTP) depends on reorganization of the dendritic spine actin cytoskeleton. The present study tested whether this involves activity-driven effects on the actin-regulatory protein cortactin, and whether such effects are disturbed in the Fmr1 knock-out (KO) model of fragile X syndrome, in which stabilization of both actin filaments and LTP is impaired. LTP induced by theta burst stimulation (TBS) in hippocampal slices from wild-type mice was associated with rapid, broadly distributed, and NMDA receptor-dependent decreases in synapse-associated cortactin. The reduction in cortactin content was blocked by blebbistatin, while basal levels were reduced by nocodazole, indicating that cortactin's movements into and away from synapses are regulated by microtubule and actomyosin motors, respectively. These results further suggest that synapse-specific LTP influences cytoskeletal elements at distant connections. The rapid effects of TBS on synaptic cortactin content were absent in Fmr1 KOs as was evidence for activity-driven phosphorylation of the protein or its upstream kinase, ERK1/2. Phosphorylation regulates cortactin's interactions with actin, and coprecipitation of the two proteins was reduced in the KOs. We propose that, in the KOs, excessive basal phosphorylation of ERK1/2 disrupts its interactions with cortactin, thereby blocking the latter protein's use of actomyosin transport systems. These impairments are predicted to compromise the response of the subsynaptic cytoskeleton to learning-related afferent activity, both locally and at distant sites.
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79
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Slanina H, Hebling S, Hauck CR, Schubert-Unkmeir A. Cell invasion by Neisseria meningitidis requires a functional interplay between the focal adhesion kinase, Src and cortactin. PLoS One 2012; 7:e39613. [PMID: 22768099 PMCID: PMC3387252 DOI: 10.1371/journal.pone.0039613] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Accepted: 05/23/2012] [Indexed: 02/07/2023] Open
Abstract
Entry of Neisseria meningitidis (the meningococcus) into human brain microvascular endothelial cells (HBMEC) is mediated by fibronectin or vitronectin bound to the surface protein Opc forming a bridge to the respective integrins. This interaction leads to cytoskeletal rearrangement and uptake of meningococci. In this study, we determined that the focal adhesion kinase (FAK), which directly associates with integrins, is involved in integrin-mediated internalization of N. meningitidis in HBMEC. Inhibition of FAK activity by the specific FAK inhibitor PF 573882 reduced Opc-mediated invasion of HBMEC more than 90%. Moreover, overexpression of FAK mutants that were either impaired in the kinase activity or were not capable of autophosphorylation or overexpression of the dominant-negative version of FAK (FRNK) blocked integrin-mediated internalization of N. meningitidis. Importantly, FAK-deficient fibroblasts were significantly less invaded by N. meningitidis. Furthermore, N. meningitidis induced tyrosine phosphorylation of several host proteins including the FAK/Src complex substrate cortactin. Inhibition of cortactin expression by siRNA silencing and mutation of critical amino acid residues within cortactin, that encompass Arp2/3 association and dynamin binding, significantly reduced meningococcal invasion into eukaryotic cells suggesting that both domains are critical for efficient uptake of N. meningitidis into eukaryotic cells. Together, these results indicate that N. meningitidis exploits the integrin signal pathway for its entry and that FAK mediates the transfer of signals from activated integrins to the cytoskeleton. A cooperative interplay between FAK, Src and cortactin then enables endocytosis of N. meningitidis into host cells.
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Affiliation(s)
- Heiko Slanina
- Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | - Sabrina Hebling
- Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
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80
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Rosales EM, Aguilera MO, Salinas RP, Carminati SA, Colombo MI, Martinez-Quiles N, Berón W. Cortactin is involved in the entry of Coxiella burnetii into non-phagocytic cells. PLoS One 2012; 7:e39348. [PMID: 22761768 PMCID: PMC3382237 DOI: 10.1371/journal.pone.0039348] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Accepted: 05/24/2012] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Cortactin is a key regulator of the actin cytoskeleton and is involved in pathogen-host cell interactions. Numerous pathogens exploit the phagocytic process and actin cytoskeleton to infect host cells. Coxiella burnetii, the etiologic agent of Q fever, is internalized by host cells through a molecular mechanism that is poorly understood. METHODOLOGY/PRINCIPAL FINDING Here we analyzed the role of different cortactin motifs in the internalization of C. burnetii by non-phagocytic cells. C. burnetii internalization into HeLa cells was significantly reduced when the cells expressed GFP-cortactin W525K, which carries a mutation in the SH3 domain that renders the protein unable to bind targets such as N-WASP. However, internalization was unaffected when the cells expressed the W22A mutant, which has a mutation in the N-terminal acidic region that destroys the protein's ability to bind and activate Arp2/3. We also determined whether the phosphorylation status of cortactin is important for internalization. Expression of GFP-cortactin 3F, which lacks phosphorylatable tyrosines, significantly increased internalization of C. burnetii, while expression of GFP-cortactin 3D, a phosphotyrosine mimic, did not affect it. In contrast, expression of GFP-cortactin 2A, which lacks phosphorylatable serines, inhibited C. burnetii internalization, while expression of GFP-cortactin SD, a phosphoserine mimic, did not affect it. Interestingly, inhibitors of Src kinase and the MEK-ERK kinase pathway blocked internalization. In fact, both kinases reached maximal activity at 15 min of C. burnetii infection, after which activity decreased to basal levels. Despite the decrease in kinase activity, cortactin phosphorylation at Tyr421 reached a peak at 1 h of infection. CONCLUSIONS/SIGNIFICANCE Our results suggest that the SH3 domain of cortactin is implicated in C. burnetii entry into HeLa cells. Furthermore, cortactin phosphorylation at serine and dephosphorylation at tyrosine favor C. burnetii internalization. We present evidence that ERK and Src kinases play a role early in infection by this pathogen.
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Affiliation(s)
- Eliana M. Rosales
- Instituto de Histología y Embriología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo - CONICET, Mendoza, Argentina
| | - Milton O. Aguilera
- Instituto de Histología y Embriología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo - CONICET, Mendoza, Argentina
| | - Romina P. Salinas
- Instituto de Histología y Embriología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo - CONICET, Mendoza, Argentina
| | - Sergio A. Carminati
- Instituto de Histología y Embriología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo - CONICET, Mendoza, Argentina
| | - María I. Colombo
- Instituto de Histología y Embriología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo - CONICET, Mendoza, Argentina
| | | | - Walter Berón
- Instituto de Histología y Embriología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo - CONICET, Mendoza, Argentina
- * E-mail:
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81
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Cortactin-binding protein 2 modulates the mobility of cortactin and regulates dendritic spine formation and maintenance. J Neurosci 2012; 32:1043-55. [PMID: 22262902 DOI: 10.1523/jneurosci.4405-11.2012] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Dendritic spines, the actin-rich protrusions emerging from dendrites, are the locations of excitatory synapses in mammalian brains. Many molecules that regulate actin dynamics also influence the morphology and/or density of dendritic spines. Since dendritic spines are neuron-specific subcellular structures, neuron-specific proteins or signals are expected to control spinogenesis. In this report, we characterize the distribution and function of neuron-predominant cortactin-binding protein 2 (CTTNBP2) in rodents. An analysis of an Expressed Sequence Tag database revealed three splice variants of mouse CTTNBP2: short, long, and intron. Immunoblotting indicated that the short form is the dominant CTTNBP2 variant in the brain. CTTNBP2 proteins were highly concentrated at dendritic spines in cultured rat hippocampal neurons as well as in the mouse brain. Knockdown of CTTNBP2 in neurons reduced the density and size of dendritic spines. Consistent with these morphological changes, the frequencies of miniature EPSCs in CTTNBP2 knockdown neurons were lower than those in control neurons. Cortactin acts downstream of CTTNBP2 in spinogenesis, as the defects caused by CTTNBP2 knockdown were rescued by overexpression of cortactin but not expression of a CTTNBP2 mutant protein lacking the cortactin interaction. Finally, immunofluorescence staining demonstrated that, unlike cortactin, CTTNBP2 stably resided at dendritic spines even after glutamate stimulation. Fluorescence recovery after photobleaching further suggested that CTTNBP2 modulates the mobility of cortactin in neurons. CTTNBP2 may thus help to immobilize cortactin in dendritic spines and control the density of dendritic spines.
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82
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Rajadurai CV, Havrylov S, Zaoui K, Vaillancourt R, Stuible M, Naujokas M, Zuo D, Tremblay ML, Park M. Met receptor tyrosine kinase signals through a cortactin-Gab1 scaffold complex, to mediate invadopodia. J Cell Sci 2012; 125:2940-53. [PMID: 22366451 PMCID: PMC3434810 DOI: 10.1242/jcs.100834] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Invasive carcinoma cells form actin-rich matrix-degrading protrusions called invadopodia. These structures resemble podosomes produced by some normal cells and play a crucial role in extracellular matrix remodeling. In cancer, formation of invadopodia is strongly associated with invasive potential. Although deregulated signals from the receptor tyrosine kinase Met (also known as hepatocyte growth factor are linked to cancer metastasis and poor prognosis, its role in invadopodia formation is not known. Here we show that stimulation of breast cancer cells with the ligand for Met, hepatocyte growth factor, promotes invadopodia formation, and in aggressive gastric tumor cells where Met is amplified, invadopodia formation is dependent on Met activity. Using both GRB2-associated-binding protein 1 (Gab1)-null fibroblasts and specific knockdown of Gab1 in tumor cells we show that Met-mediated invadopodia formation and cell invasion requires the scaffold protein Gab1. By a structure–function approach, we demonstrate that two proline-rich motifs (P4/5) within Gab1 are essential for invadopodia formation. We identify the actin regulatory protein, cortactin, as a direct interaction partner for Gab1 and show that a Gab1–cortactin interaction is dependent on the SH3 domain of cortactin and the integrity of the P4/5 region of Gab1. Both cortactin and Gab1 localize to invadopodia rosettes in Met-transformed cells and the specific uncoupling of cortactin from Gab1 abrogates invadopodia biogenesis and cell invasion downstream from the Met receptor tyrosine kinase. Met localizes to invadopodia along with cortactin and promotes phosphorylation of cortactin. These findings provide insights into the molecular mechanisms of invadopodia formation and identify Gab1 as a scaffold protein involved in this process.
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Affiliation(s)
- Charles V Rajadurai
- Department of Biochemistry, McGill University, Montréal Québec H3A 1Y6, Canada
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83
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Grigera PR, Ma L, Borgman CA, Pinto AF, Sherman NE, Parsons JT, Fox JW. Mass spectrometric analysis identifies a cortactin-RCC2/TD60 interaction in mitotic cells. J Proteomics 2012; 75:2153-9. [PMID: 22282019 DOI: 10.1016/j.jprot.2012.01.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 01/08/2012] [Accepted: 01/09/2012] [Indexed: 10/24/2022]
Abstract
Cortactin is an F-actin binding protein that functions as a scaffold to regulate Arp2/3 mediated actin polymerization in lamellipodia and invadopodia formation as well as functioning in cell migration and endocytosis of many different cell types. In light of the fact that regulated actin polymerization is critical for many cellular processes we launched a search for novel cortactin interactions with cellular proteins that might indicate heretofore undescribed biological activities supported by cortactin. Using a modified stable isotope labeling in cell culture (SILAC) approach in HEK293 cells and Flag-tagged cortactin (F-cortactin) as bait, we identified a limited set of cortactin interactions including several proteins which have not previously been identified as cortactin associated proteins. Among these were serine/threonine-protein phosphatase 2A subunit beta (PP2A-beta) and RCC2/TD60, a Rac guanine nucleotide exchange factor (GEF) required for completion of mitosis and cytokinesis. The interaction between cortactin and RCC2/TD60 was verified in cell lysates immunoprecitated with anti-RCC2/TD60 antibody. Furthermore, cortactin was localized by immunofluorescence in the equatorial plane of dividing HeLa cells in the region where RCC2/TD60 has previously been localized thus providing support for a complex containing cortactin and RCC2/TD60 complex that may play a functional role in cells undergoing mitosis.
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Affiliation(s)
- Pablo R Grigera
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia Health System, Charlottesville, VA 22908, United States
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84
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Abstract
Presynaptic compartments are formed through the recruitment of preassembled clusters of proteins to points of cell-cell contact, however, the molecular mechanism(s) underlying this process remains unclear. We demonstrate that clusters of polymerized actin can recruit and maintain synaptic vesicles to discrete sites along the axon, and that cadherin/β-catenin/scribble/β-pix complexes play an important role in this event. Previous work has demonstrated that β-catenin and scribble are important for the clustering of vesicles at synapses. We demonstrate that β-pix, a Rac/Cdc42 guanine nucleotide exchange factor (GEF), forms a complex with cadherin, β-catenin, and scribble at synapses and enhances localized actin polymerization in rat hippocampal neurons. In cells expressing β-pix siRNA or dominant-negative β-pix that lacks its GEF activity, actin polymerization at synapses is dramatically reduced, and synaptic vesicle localization is disrupted. This β-pix phenotype can be rescued by cortactin overexpression, suggesting that β-pix-mediated actin polymerization at synapses regulates vesicle localization.
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85
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Agrin triggers the clustering of raft-associated acetylcholine receptors through actin cytoskeleton reorganization. Biol Cell 2011; 103:287-301. [PMID: 21524273 DOI: 10.1042/bc20110018] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND INFORMATION Cholesterol/sphingolipid-rich membrane microdomains or membrane rafts have been implicated in various aspects of receptor function such as activation, trafficking and synapse localization. More specifically in muscle, membrane rafts are involved in AChR (acetylcholine receptor) clustering triggered by the neural factor agrin, a mechanism considered integral to NMJ (neuromuscular junction) formation. In addition, actin polymerization is required for the formation and stabilization of AChR clusters in muscle fibres. Since membrane rafts are platforms sustaining actin nucleation, we hypothesize that these microdomains provide the suitable microenvironment favouring agrin/MuSK (muscle-specific kinase) signalling, eliciting in turn actin cytoskeleton reorganization and AChR clustering. However, the identity of the signalling pathways operating through these microdomains still remains unclear. RESULTS In this work, we attempted to identify the interactions between membrane raft components and cortical skeleton that regulate, upon signalling by agrin, the assembly and stabilization of synaptic proteins of the postsynaptic membrane domain at the NMJ. We provide evidence that in C2C12 myotubes, agrin triggers the association of a subset of membrane rafts enriched in AChR, the -MuSK and Cdc42 (cell division cycle 42) to the actin cytoskeleton. Disruption of the liquid-ordered phase by methyl-β-cyclodextrin abolished this association. We further show that actin and the actin-nucleation factors, N-WASP (neuronal Wiscott-Aldrich syndrome protein) and Arp2/3 (actin-related protein 2/3) are transiently associated with rafts on agrin engagement. Consistent with these observations, pharmacological inhibition of N-WASP activity perturbed agrin-elicited AChR clustering. Finally, immunoelectron microscopic analyses of myotube membrane uncovered that AChRs were constitutively associated with raft nanodomains at steady state that progressively coalesced on agrin activation. These rearrangements of membrane domains correlated with the reorganization of cortical actin cytoskeleton through concomitant and transient recruitment of the Arp2/3 complex to AChR-enriched rafts. CONCLUSIONS The present observations support the notion that membrane rafts are involved in AChR clustering by promoting local actin cytoskeleton reorganization through the recruitment of effectors of the agrin/MuSK signalling cascade. These mechanisms are believed to play an important role in vivo in the formation of the NMJ.
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86
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Tegtmeyer N, Wittelsberger R, Hartig R, Wessler S, Martinez-Quiles N, Backert S. Serine phosphorylation of cortactin controls focal adhesion kinase activity and cell scattering induced by Helicobacter pylori. Cell Host Microbe 2011; 9:520-31. [PMID: 21669400 DOI: 10.1016/j.chom.2011.05.007] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Revised: 04/29/2011] [Accepted: 05/25/2011] [Indexed: 02/04/2023]
Abstract
Cell migration and invasion require the coordinated regulation of cytoskeletal architectural changes by signaling factors, including the actin-binding protein cortactin. Bacterial and viral pathogens subvert these signaling factors to promote their uptake, spread and dissemination. We show that the gastric pathogen Helicobacter pylori (Hp) targets cortactin by two independent processes leading to its tyrosine dephosphorylation and serine phosphorylation to regulate cell scattering and elongation. The phosphorylation status of cortactin dictates its subcellular localization and signaling partners. Upon infection, cortactin was found to interact with and stimulate the kinase activity of focal adhesion kinase (FAK). This interaction required the SH3 domain and phosphorylation of cortactin at serine 405 and a proline-rich sequence in FAK. Using Hp as a model, this study unravels a previously unrecognized FAK activation pathway. We propose that Hp targets cortactin to protect the gastric epithelium from excessive cell lifting and ensure sustained infection in the stomach.
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Affiliation(s)
- Nicole Tegtmeyer
- Department of Microbiology, Otto von Guericke University, Leipziger Strasse 44, D-39120 Magdeburg, Germany
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87
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Class IIb HDAC6 regulates endothelial cell migration and angiogenesis by deacetylation of cortactin. EMBO J 2011; 30:4142-56. [PMID: 21847094 DOI: 10.1038/emboj.2011.298] [Citation(s) in RCA: 157] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Accepted: 07/26/2011] [Indexed: 11/08/2022] Open
Abstract
Histone deacetylases (HDACs) deacetylate histones and non-histone proteins, thereby affecting protein activity and gene expression. The regulation and function of the cytoplasmic class IIb HDAC6 in endothelial cells (ECs) is largely unexplored. Here, we demonstrate that HDAC6 is upregulated by hypoxia and is essential for angiogenesis. Silencing of HDAC6 in ECs decreases sprouting and migration in vitro and formation of functional vascular networks in matrigel plugs in vivo. HDAC6 regulates zebrafish vessel formation, and HDAC6-deficient mice showed a reduced formation of perfused vessels in matrigel plugs. Consistently, overexpression of wild-type HDAC6 increases sprouting from spheroids. HDAC6 function requires the catalytic activity but is independent of ubiquitin binding and deacetylation of α-tubulin. Instead, we found that HDAC6 interacts with and deacetylates the actin-remodelling protein cortactin in ECs, which is essential for zebrafish vessel formation and which mediates the angiogenic effect of HDAC6. In summary, we show that HDAC6 is necessary for angiogenesis in vivo and in vitro, involving the interaction and deacetylation of cortactin that regulates EC migration and sprouting.
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88
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Schnoor M, Lai FPL, Zarbock A, Kläver R, Polaschegg C, Schulte D, Weich HA, Oelkers JM, Rottner K, Vestweber D. Cortactin deficiency is associated with reduced neutrophil recruitment but increased vascular permeability in vivo. ACTA ACUST UNITED AC 2011; 208:1721-35. [PMID: 21788407 PMCID: PMC3149227 DOI: 10.1084/jem.20101920] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Cortactin is required for endothelial barrier function and leukocyte recruitment in vivo. Neutrophil extravasation and the regulation of vascular permeability require dynamic actin rearrangements in the endothelium. In this study, we analyzed in vivo whether these processes require the function of the actin nucleation–promoting factor cortactin. Basal vascular permeability for high molecular weight substances was enhanced in cortactin-deficient mice. Despite this leakiness, neutrophil extravasation in the tumor necrosis factor–stimulated cremaster was inhibited by the loss of cortactin. The permeability defect was caused by reduced levels of activated Rap1 (Ras-related protein 1) in endothelial cells and could be rescued by activating Rap1 via the guanosine triphosphatase (GTPase) exchange factor EPAC (exchange protein directly activated by cAMP). The defect in neutrophil extravasation was caused by enhanced rolling velocity and reduced adhesion in postcapillary venules. Impaired rolling interactions were linked to contributions of β2-integrin ligands, and firm adhesion was compromised by reduced ICAM-1 (intercellular adhesion molecule 1) clustering around neutrophils. A signaling process known to be critical for the formation of ICAM-1–enriched contact areas and for transendothelial migration, the ICAM-1–mediated activation of the GTPase RhoG was blocked in cortactin-deficient endothelial cells. Our results represent the first physiological evidence that cortactin is crucial for orchestrating the molecular events leading to proper endothelial barrier function and leukocyte recruitment in vivo.
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Affiliation(s)
- Michael Schnoor
- Max Planck Institute for Molecular Biomedicine, D 48149 Münster, Germany
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89
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Baumgartner M. Enforcing host cell polarity: an apicomplexan parasite strategy towards dissemination. Curr Opin Microbiol 2011; 14:436-44. [PMID: 21795099 DOI: 10.1016/j.mib.2011.07.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Accepted: 07/01/2011] [Indexed: 10/25/2022]
Abstract
The propagation of apicomplexan parasites through transmitting vectors is dependent on effective dissemination of parasites inside the mammalian host. Intracellular Toxoplasma and Theileria parasites face the challenge that their spread inside the host depends in part on the motile capacities of their host cells. In response, these parasites influence the efficiency of dissemination by altering adhesive and/or motile properties of their host cells. Theileria parasites do so by targeting signalling pathways that control host cell actin dynamics. The resulting enforced polar host cell morphology facilitates motility and invasiveness, by establishing focal adhesion and invasion structures at the leading edge of the infected cell. This parasite strategy highlights mechanisms of motility regulation that are also likely relevant for immune or cancer cell motility.
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Affiliation(s)
- Martin Baumgartner
- University of Bern, Vetsuisse Faculty, Molecular Pathobiology, Länggassstrasse 122, CH-3012 Bern, Switzerland.
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90
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Myosin IIB deficiency in embryonic fibroblasts affects regulators and core members of the par polarity complex. Histochem Cell Biol 2011; 136:245-66. [PMID: 21785947 DOI: 10.1007/s00418-011-0840-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/06/2011] [Indexed: 10/24/2022]
Abstract
Wild-type (WT) and myosin heavy chain IIB null [MHCIIB (-/-)] embryonic fibroblasts were used as an experimental model to assess the role of the isoform B of myosin II (MII) in the regulation of the cell shape and intrinsic polarity. Genetic ablation of MHCIIB causes a persistent albeit, unstable protrusive activity in embryonic fibroblasts (Lo et al. in Nonmuscle myosin IIB is involved in the guidance of fibroblast migration. Mol Biol Cell 15:982-989, 2004). Here, we show that MHCIIB-deficient fibroblasts are characterized by a sustained guanine nucleotide exchange factor (GEF)-dependent activation of the small GTPase Rac-1 that is responsible for the continual lamellipodium formation. Moreover, we observed a sustained PKC-ζ activation and an increased association of cortactin with the plasma membrane in the MHCIIB (-/-) cells that were also dependent on GEF-mediated Rac-1 activation. Rac-1 activation and its downstream effects were induced in WT fibroblasts by inhibiting MII ATPase and crosslinking activities, suggesting that an altered actin-MII interaction favours Rac-1 activation, regardless of the MII isoform implicated. In addition, we found MIIB isoform-specific effects that were independent of Rac-1 activation. MHCIIA interacts with cortactin whereas MHCIIB does not. By contrast, MHCIIB interacts with Lgl1, a member of the Scribble/Dlg/Lgl polarity complex, whereas MHCIIA does not. MHCIIB (-/-) fibroblasts exhibited deregulated endogenous levels of the Par polarity complex members, Par3 and Par6. Together, the data show that MHCIIB deficiency causes imbalances in signalling pathways that are responsible for cell polarity determination. The results suggest that these pathways are targets of MIIB in the regulation of the cell's shape and polarity.
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91
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Ilatovskaya DV, Pavlov TS, Levchenko V, Negulyaev YA, Staruschenko A. Cortical actin binding protein cortactin mediates ENaC activity via Arp2/3 complex. FASEB J 2011; 25:2688-99. [PMID: 21536685 DOI: 10.1096/fj.10-167262] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Epithelial Na(+) channel (ENaC) activity is regulated, in part, by the cortical cytoskeleton. Here we demonstrate that cortactin is highly expressed in the kidney cortex and polarized epithelial cells, and is localized to the cortical collecting duct. Coexpression of cortactin with ENaC decreases ENaC activity, as measured in patch-clamp experiments. Biotinylation experiments and single-channel analysis reveal that cortactin decreases ENaC activity via affecting channel open probability (P(o)). Knockdown of cortactin in mpkCCD(c14) principal cells results in an increase in ENaC activity and sodium reabsorption. Coimmunoprecipitation analysis shows direct interactions between cortactin and all three ENaC subunits in cultured and native cells. To address the question of what mechanism underlies the action of cortactin on ENaC activity, we assayed the effects of various mutants of cortactin. The data show that only a cortactin mutant unable to bind Arp2/3 complex does not influence ENaC activity. Furthermore, inhibitor of the Arp2/3 complex CK-0944666 precludes the effect of cortactin. Depolymerization of the actin microfilaments and inhibition of the Arp2/3 complex does not result in the loss of association between ENaC and cortactin. Thus, these results indicate that cortactin is functionally important for ENaC activity and that Arp2/3 complex is involved in this mechanism.
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Affiliation(s)
- Daria V Ilatovskaya
- Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI 53226, USA
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92
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von Holleben M, Gohla A, Janssen KP, Iritani BM, Beer-Hammer S. Immunoinhibitory adapter protein Src homology domain 3 lymphocyte protein 2 (SLy2) regulates actin dynamics and B cell spreading. J Biol Chem 2011; 286:13489-501. [PMID: 21296879 DOI: 10.1074/jbc.m110.155184] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Appropriate B cell activation is essential for adaptive immunity. In contrast to the molecular mechanisms that regulate positive signaling in immune responses, the counterbalancing negative regulatory pathways remain insufficiently understood. The Src homology domain 3 (SH3)-containing adapter protein SH3 lymphocyte protein 2 (SLy2, also known as hematopoietic adapter-containing SH3 and sterile α-motif (SAM) domains 1; HACS1) is strongly up-regulated upon B cell activation and functions as an endogenous immunoinhibitor in vivo, but the underlying molecular mechanisms of SLy2 function have been elusive. We have generated transgenic mice overexpressing SLy2 in B and T cells and have studied the biological effects of elevated SLy2 levels in Jurkat and HeLa cells. Our results demonstrate that SLy2 induces Rac1-dependent membrane ruffle formation and regulates cell spreading and polarization and that the SLy2 SH3 domain is essential for these effects. Using immunoprecipitation and confocal microscopy, we provide evidence that the actin nucleation-promoting factor cortactin is an SH3 domain-directed interaction partner of SLy2. Consistent with an important role of SLy2 for actin cytoskeletal reorganization, we further show that SLy2-transgenic B cells are severely defective in cell spreading. Together, our findings extend our mechanistic understanding of the immunoinhibitory roles of SLy2 in vivo and suggest that the physiological up-regulation of SLy2 observed upon B cell activation functions to counteract excessive B cell spreading.
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Affiliation(s)
- Max von Holleben
- Institute of Medical Microbiology and Hospital Hygiene, Heinrich Heine University, 40225 Duesseldorf, Germany
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93
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Godin LM, Vergen J, Prakash YS, Pagano RE, Hubmayr RD. Spatiotemporal dynamics of actin remodeling and endomembrane trafficking in alveolar epithelial type I cell wound healing. Am J Physiol Lung Cell Mol Physiol 2011; 300:L615-23. [PMID: 21216977 DOI: 10.1152/ajplung.00265.2010] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Alveolar epithelial type I cell (ATI) wounding is prevalent in ventilator-injured lungs and likely contributes to pathogenesis of "barotrauma" and "biotrauma." In experimental models most wounded alveolar cells repair plasma membrane (PM) defects and survive insults. Considering the force balance between edge energy at the PM wound margins and adhesive interactions of the lipid bilayer with the underlying cytoskeleton (CSK), we tested the hypothesis that subcortical actin depolymerization is a key facilitator of PM repair. Using real-time fluorescence imaging of primary rat ATI transfected with a live cell actin-green fluorescent protein construct (Lifeact-GFP) and loaded with N-rhodamine phosphatidylethanolamine (PE), we examined the spatial and temporal coordination between cytoskeletal remodeling and PM repair following micropuncture. Membrane integrity was inferred from the fluorescence intensity profiles of the cytosolic label calcein AM. Wounding led to rapid depolymerization of the actin CSK near the wound site, concurrent with accumulation of endomembrane-derived N-rhodamine PE. Both responses were sustained until PM integrity was reestablished, which typically occurs between ∼10 and 40 s after micropuncture. Only thereafter did the actin CSK near the wound begin to repolymerize, while the rate of endomembrane lipid accumulation decreased. Between 60 and 90 s after successful PM repair, after translocation of the actin nucleation factor cortactin, a dense actin fiber network formed. In cells that did not survive micropuncture injury, actin remodeling did not occur. These novel results highlight the importance of actin remodeling in ATI cell repair and suggest molecular targets for modulating the repair process.
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Affiliation(s)
- Lindsay M Godin
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
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94
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Häussinger D, Reinehr R. Osmotic Regulation of Bile Acid Transport, Apoptosis and Proliferation in Rat Liver. Cell Physiol Biochem 2011; 28:1089-98. [DOI: 10.1159/000335845] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/03/2011] [Indexed: 01/04/2023] Open
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95
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Baumgartner M. Theileria annulata promotes Src kinase-dependent host cell polarization by manipulating actin dynamics in podosomes and lamellipodia. Cell Microbiol 2010; 13:538-53. [DOI: 10.1111/j.1462-5822.2010.01553.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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96
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Kelley LC, Hayes KE, Ammer AG, Martin KH, Weed SA. Cortactin phosphorylated by ERK1/2 localizes to sites of dynamic actin regulation and is required for carcinoma lamellipodia persistence. PLoS One 2010; 5:e13847. [PMID: 21079800 PMCID: PMC2973953 DOI: 10.1371/journal.pone.0013847] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Accepted: 10/18/2010] [Indexed: 01/06/2023] Open
Abstract
Background Tumor cell motility and invasion is governed by dynamic regulation of the cortical actin cytoskeleton. The actin-binding protein cortactin is commonly upregulated in multiple cancer types and is associated with increased cell migration. Cortactin regulates actin nucleation through the actin related protein (Arp)2/3 complex and stabilizes the cortical actin cytoskeleton. Cortactin is regulated by multiple phosphorylation events, including phosphorylation of S405 and S418 by extracellular regulated kinases (ERK)1/2. ERK1/2 phosphorylation of cortactin has emerged as an important positive regulatory modification, enabling cortactin to bind and activate the Arp2/3 regulator neuronal Wiskott-Aldrich syndrome protein (N-WASp), promoting actin polymerization and enhancing tumor cell movement. Methodology/Principal Findings In this report we have developed phosphorylation-specific antibodies against phosphorylated cortactin S405 and S418 to analyze the subcellular localization of this cortactin form in tumor cells and patient samples by microscopy. We evaluated the interplay between cortactin S405 and S418 phosphorylation with cortactin tyrosine phosphorylation in regulating cortactin conformational forms by Western blotting. Cortactin is simultaneously phosphorylated at S405/418 and Y421 in tumor cells, and through the use of point mutant constructs we determined that serine and tyrosine phosphorylation events lack any co-dependency. Expression of S405/418 phosphorylation-null constructs impaired carcinoma motility and adhesion, and also inhibited lamellipodia persistence monitored by live cell imaging. Conclusions/Significance Cortactin phosphorylated at S405/418 is localized to sites of dynamic actin assembly in tumor cells. Concurrent phosphorylation of cortactin by ERK1/2 and tyrosine kinases enables cells with the ability to regulate actin dynamics through N-WASp and other effector proteins by synchronizing upstream regulatory pathways, confirming cortactin as an important integration point in actin-based signal transduction. Reduced lamellipodia persistence in cells with S405/418A expression identifies an essential motility-based process reliant on ERK1/2 signaling, providing additional understanding as to how this pathway impacts tumor cell migration.
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Affiliation(s)
- Laura C. Kelley
- Department of Neurobiology and Anatomy, Program in Cancer Cell Biology, Mary Babb Randolph Cancer Center, West Virginia University, Morgantown, West Virginia, United States of America
| | - Karen E. Hayes
- Department of Neurobiology and Anatomy, Program in Cancer Cell Biology, Mary Babb Randolph Cancer Center, West Virginia University, Morgantown, West Virginia, United States of America
| | - Amanda Gatesman Ammer
- Department of Neurobiology and Anatomy, Program in Cancer Cell Biology, Mary Babb Randolph Cancer Center, West Virginia University, Morgantown, West Virginia, United States of America
| | - Karen H. Martin
- Department of Neurobiology and Anatomy, Program in Cancer Cell Biology, Mary Babb Randolph Cancer Center, West Virginia University, Morgantown, West Virginia, United States of America
| | - Scott A. Weed
- Department of Neurobiology and Anatomy, Program in Cancer Cell Biology, Mary Babb Randolph Cancer Center, West Virginia University, Morgantown, West Virginia, United States of America
- * E-mail:
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97
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Bershteyn M, Atwood SX, Woo WM, Li M, Oro AE. MIM and cortactin antagonism regulates ciliogenesis and hedgehog signaling. Dev Cell 2010; 19:270-83. [PMID: 20708589 DOI: 10.1016/j.devcel.2010.07.009] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2009] [Revised: 05/28/2010] [Accepted: 06/18/2010] [Indexed: 10/19/2022]
Abstract
The primary cilium is critical for transducing Sonic hedgehog (Shh) signaling, but the mechanisms of its transient assembly are poorly understood. Previously we showed that the actin regulatory protein Missing-in-Metastasis (MIM) regulates Shh signaling, but the nature of MIM's role was unknown. Here we show that MIM is required at the basal body of mesenchymal cells for cilia maintenance, Shh responsiveness, and de novo hair follicle formation. MIM knockdown results in increased Src kinase activity and subsequent hyperphosphorylation of the actin regulator Cortactin. Importantly, inhibition of Src or depletion of Cortactin compensates for the cilia defect in MIM knockdown cells, whereas overexpression of Src or phospho-mimetic Cortactin is sufficient to inhibit ciliogenesis. Our results suggest that MIM promotes ciliogenesis by antagonizing Src-dependent phosphorylation of Cortactin and describe a mechanism linking regulation of the actin cytoskeleton with ciliogenesis and Shh signaling during tissue regeneration.
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98
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Dobrinskikh E, Giral H, Caldas YA, Levi M, Doctor RB. Shank2 redistributes with NaPilla during regulated endocytosis. Am J Physiol Cell Physiol 2010; 299:C1324-34. [PMID: 20810910 DOI: 10.1152/ajpcell.00183.2010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Serum phosphate levels are acutely impacted by the abundance of sodium-phosphate cotransporter IIa (NaPiIIa) in the apical membrane of renal proximal tubule cells. PSD-95/Disks Large/Zonula Occludens (PDZ) domain-containing proteins bind NaPiIIa and likely contribute to the delivery, retention, recovery, and trafficking of NaPiIIa. Shank2 is a distinctive PDZ domain protein that binds NaPiIIa. Its role in regulating NaPiIIa activity, distribution, and abundance is unknown. In the present in vivo study, rats were maintained on a low-phosphate diet, and then plasma phosphate levels were acutely elevated by high-phosphate feeding to induce the recovery, endocytosis, and degradation of NaPiIIa. Western blot analysis of renal cortical tissue from rats given high-phosphate feed showed NaPiIIa and Shank2 underwent degradation. Quantitative immunofluorescence analyses, including microvillar versus intracellular intensity ratios and intensity correlation quotients, showed that Shank2 redistributed with NaPiIIa during the time course of NaPiIIa endocytosis. Furthermore, NaPiIIa and Shank2 trafficked through distinct endosomal compartments (clathrin, early endosomes, lysosomes) with the same temporal pattern. These in vivo findings indicate that Shank2 is positioned to coordinate the regulated endocytic retrieval and downregulation of NaPiIIa in rat renal proximal tubule cells.
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Affiliation(s)
- Evgenia Dobrinskikh
- Department of Medicine, Anschutz Medical Center, University of Colorado, Denver, Colorado, USA
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99
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Arsenic-induced protein phosphorylation changes in HeLa cells. Anal Bioanal Chem 2010; 398:2099-107. [PMID: 20803194 DOI: 10.1007/s00216-010-4128-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2010] [Revised: 08/11/2010] [Accepted: 08/11/2010] [Indexed: 10/19/2022]
Abstract
Arsenic is well documented as a chemotherapeutic agent capable of inducing cell death while at the same time is considered a human carcinogen and an environmental contaminant. Although arsenic toxicity is well known and has formed an impressive literature over the time, little is known about how its effects are exerted at the proteome level. Protein phosphorylation is an important post-translational modification involved in the regulation of cell signaling and likely is altered by arsenic treatment. Despite the importance of phosphorylation for many regulatory processes in cells, the identification and characterization of phosphorylation, as effected by arsenic through mass spectrometric detection, are not fully studied. Here, we identify phosphorylated proteins, which are related to post-translational modifications after phenylarsine oxide (PAO) inoculation to HeLa cells. PAO was chosen because of its high cytotoxicity, measured earlier in these labs. In this study, size exclusion chromatography coupled to inductively coupled plasma mass spectrometry (SEC-ICP-MS) is used to establish several molecular weight fractions with phosphorylated proteins by monitoring (31)P signal vs. time via ICP-MS. SEC-ICP-MS fractions are collected and then separated by the nano-LC-CHIP/ITMS system for peptide determination. Spectrum Mill and MASCOT protein database search engines are used for protein identification. Several phosphorylation sites and proteins related to post-translational modifications are also identified.
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100
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Fang Z, Takizawa N, Wilson KA, Smith TC, Delprato A, Davidson MW, Lambright DG, Luna EJ. The membrane-associated protein, supervillin, accelerates F-actin-dependent rapid integrin recycling and cell motility. Traffic 2010; 11:782-99. [PMID: 20331534 DOI: 10.1111/j.1600-0854.2010.01062.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In migrating cells, the cytoskeleton coordinates signal transduction and redistribution of transmembrane proteins, including integrins and growth factor receptors. Supervillin is an F-actin- and myosin II-binding protein that tightly associates with signaling proteins in cholesterol-rich, 'lipid raft' membrane microdomains. We show here that supervillin also can localize with markers for early and sorting endosomes (EE/SE) and with overexpressed components of the Arf6 recycling pathway in the cell periphery. Supervillin tagged with the photoswitchable fluorescent protein, tdEos, moves both into and away from dynamic structures resembling podosomes at the basal cell surface. Rapid integrin recycling from EE/SE is inhibited in supervillin-knockdown cells, but the rates of integrin endocytosis and recycling from the perinuclear recycling center (PNRC) are unchanged. A lack of synergy between supervillin knockdown and the actin filament barbed-end inhibitor, cytochalasin D, suggests that both treatments affect actin-dependent rapid recycling. Supervillin also enhances signaling from the epidermal growth factor receptor (EGFR) to extracellular signal-regulated kinases (ERKs) 1 and 2 and increases the velocity of cell translocation. These results suggest that supervillin, F-actin and associated proteins coordinate a rapid, basolateral membrane recycling pathway that contributes to ERK signaling and actin-based cell motility.
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Affiliation(s)
- Zhiyou Fang
- Department of Cell Biology, University of Massachusetts Medical School, Biotech 4, Suite 306, 377 Plantation Street, Worcester, MA 01605, USA
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