301
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Abstract
It has long been thought that PTPs (protein tyrosine phosphatases) normally function as tumour suppressors. Recent high-throughput mutational analysis identified loss-of-function mutations in six PTPs in human colon cancers, providing critical cancer genetics evidence that PTPs can act as tumour suppressor genes. PTPRT (protein tyrosine phosphatase receptor-T), a member of the family of type IIB receptor-like PTPs, is the most frequently mutated PTP among them. Consistent with the notion that PTPRT is a tumour suppressor, PTPRT knockout mice are hypersensitive to AOM (azoxymethane)-induced colon cancer. The present review focuses on the physiological and pathological functions of PTPRT as well as the cellular pathways regulated by this phosphatase.
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302
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Abstract
Post-translational modifications are used by cells to link additional information to proteins. Most modifications are subtle and concern small moieties such as a phosphate group or a lipid. In contrast, protein ubiquitylation entails the covalent attachment of a full-length protein such as ubiquitin. The protein ubiquitylation machinery is remarkably complex, comprising more than 15 Ubls (ubiquitin-like proteins) and several hundreds of ubiquitin-conjugating enzymes. Ubiquitin is best known for its role as a tag that induces protein destruction either by the proteasome or through targeting to lysosomes. However, addition of one or more Ubls also affects vesicular traffic, protein-protein interactions and signal transduction. It is by now well established that ubiquitylation is a component of most, if not all, cellular signalling pathways. Owing to its abundance in controlling cellular functions, ubiquitylation is also of key relevance to human pathologies, including cancer and inflammation. In the present review, we focus on its role in the control of cell adhesion, polarity and directional migration. It will become clear that protein modification by Ubls occurs at every level from the receptors at the plasma membrane down to cytoskeletal components such as actin, with differential consequences for the pathway's final output. Since ubiquitylation is fast as well as reversible, it represents a bona fide signalling event, which is used to fine-tune a cell's responses to receptor agonists.
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303
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The diversification of the LIM superclass at the base of the metazoa increased subcellular complexity and promoted multicellular specialization. PLoS One 2012; 7:e33261. [PMID: 22438907 PMCID: PMC3305314 DOI: 10.1371/journal.pone.0033261] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Accepted: 02/07/2012] [Indexed: 01/15/2023] Open
Abstract
Background Throughout evolution, the LIM domain has been deployed in many different domain configurations, which has led to the formation of a large and distinct group of proteins. LIM proteins are involved in relaying stimuli received at the cell surface to the nucleus in order to regulate cell structure, motility, and division. Despite their fundamental roles in cellular processes and human disease, little is known about the evolution of the LIM superclass. Results We have identified and characterized all known LIM domain-containing proteins in six metazoans and three non-metazoans. In addition, we performed a phylogenetic analysis on all LIM domains and, in the process, have identified a number of novel non-LIM domains and motifs in each of these proteins. Based on these results, we have formalized a classification system for LIM proteins, provided reasonable timing for class and family origin events; and identified lineage-specific loss events. Our analysis is the first detailed description of the full set of LIM proteins from the non-bilaterian species examined in this study. Conclusion Six of the 14 LIM classes originated in the stem lineage of the Metazoa. The expansion of the LIM superclass at the base of the Metazoa undoubtedly contributed to the increase in subcellular complexity required for the transition from a unicellular to multicellular lifestyle and, as such, was a critically important event in the history of animal multicellularity.
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304
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Ohsawa K, Sanagi T, Nakamura Y, Suzuki E, Inoue K, Kohsaka S. Adenosine A3 receptor is involved in ADP-induced microglial process extension and migration. J Neurochem 2012; 121:217-27. [PMID: 22335470 DOI: 10.1111/j.1471-4159.2012.07693.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The extension of microglial processes toward injured sites in the brain is triggered by the stimulation of the purinergic receptor P2Y(12) by extracellular ATP. We recently showed that P2Y(12) stimulation by ATP induces microglial process extension in collagen gels. In the present study, we found that a P2Y(12) agonist, 2-methylthio-ADP (2MeSADP), failed to induce the process extension of microglia in collagen gels and that co-stimulation with adenosine, a phosphohydrolytic derivative of ATP, and 2MeSADP restored the chemotactic process extension. An adenosine A3 receptor (A3R)-selective agonist restored the chemotactic process extension, but other receptor subtype agonists did not. The removal of adenosine by adenosine deaminase and the blocking of A3R by an A3R-selective antagonist inhibited ADP-induced process extension. The A3R antagonist inhibited ADP-induced microglial migration, and an A3R agonist promoted 2MeSADP-stimulated migration. ADP and the A3R agonist activated Jun N-terminal kinase in microglia, and a Jun N-terminal kinase inhibitor inhibited the ADP-induced process extension. An RT-PCR analysis showed that A1R and A3R were expressed by microglia sorted from adult rat brains and that the A2AR expression level was very low. These results suggested that A3R signaling may be involved in the ADP-induced process extension and migration of microglia.
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Affiliation(s)
- Keiko Ohsawa
- Department of Neurochemistry, National Institute of Neuroscience, 4-1-1 Ogawahigashi Kodaira, Tokyo 187-8502, Japan
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305
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Lamouille S, Connolly E, Smyth JW, Akhurst RJ, Derynck R. TGF-β-induced activation of mTOR complex 2 drives epithelial-mesenchymal transition and cell invasion. J Cell Sci 2012; 125:1259-73. [PMID: 22399812 DOI: 10.1242/jcs.095299] [Citation(s) in RCA: 250] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In cancer progression, carcinoma cells gain invasive behavior through a loss of epithelial characteristics and acquisition of mesenchymal properties, a process that can lead to epithelial-mesenchymal transition (EMT). TGF-β is a potent inducer of EMT, and increased TGF-β signaling in cancer cells is thought to drive cancer-associated EMT. Here, we examine the physiological requirement for mTOR complex 2 (mTORC2) in cells undergoing EMT. TGF-β rapidly induces mTORC2 kinase activity in cells undergoing EMT, and controls epithelial cell progression through EMT. By regulating EMT-associated cytoskeletal changes and gene expression, mTORC2 is required for cell migration and invasion. Furthermore, inactivation of mTORC2 prevents cancer cell dissemination in vivo. Our results suggest that the mTORC2 pathway is an essential downstream branch of TGF-β signaling, and represents a responsive target to inhibit EMT and prevent cancer cell invasion and metastasis.
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Affiliation(s)
- Samy Lamouille
- Department of Cell and Tissue Biology, University of California at San Francisco, San Francisco, CA 94143-0512, USA
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306
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Abstract
Urokinase-type plasminogen activator (uPA) and its receptor, uPAR, play important roles in promoting cancer cell adhesion, migration and invasion. Rho GTPases are key coordinators of these processes; the Rho GTPase Rac1 has previously been implicated in uPA- and/or uPAR-induced migratory or morphological cell responses. We used RNAi to deplete 12 different Rho GTPases to screen for effects on uPA-stimulated migration, and found that depletion of RhoB significantly reduces uPA-induced migration and invasion of prostate carcinoma cells. RhoB depletion did not affect the expression or surface levels of uPAR but reduced the uPAR-induced increase in levels of several integrins and inhibited uPAR signalling to the actin regulator cofilin, the cell-adhesion signal-transduction adaptor molecule paxillin and the serine/threonine kinase Akt. uPAR rapidly activated RhoB and increased RhoB expression. RhoB depletion also reduced cell adhesion to and spreading on vitronectin, which is a uPAR ligand. This correlated with decreased association between integrins and uPAR and reduced integrin β1 activity. Our results indicate that RhoB is a key regulator of uPAR signalling in cell adhesion, migration and invasion.
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Affiliation(s)
- Daniela Alfano
- Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, London, UK
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307
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Macrophage Migration and Its Regulation by CSF-1. Int J Cell Biol 2012; 2012:501962. [PMID: 22505929 PMCID: PMC3296313 DOI: 10.1155/2012/501962] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 11/04/2011] [Accepted: 11/04/2011] [Indexed: 02/06/2023] Open
Abstract
Macrophages are terminally differentiated cells of the mononuclear phagocytic lineage and develop under the stimulus of their primary growth and differentiation factor, CSF-1. Although they differentiate into heterogeneous populations, depending upon their tissue of residence, motility is an important aspect of their function. To facilitate their migration through tissues, macrophages express a unique range of adhesion and cytoskeletal proteins. Notably, macrophages do not form large, stable adhesions or actin stress fibers but rely on small, short lived point contacts, focal complexes and podosomes for traction. Thus, macrophages are built to respond rapidly to migratory stimuli. As well as triggering growth and differentiation, CSF-1 is also a chemokine that regulates macrophage migration via activation the CSF-1 receptor tyrosine kinase. CSF-1R autophosphorylation of several intracellular tyrosine residues leads to association and activation of many downstream signaling molecules. However, phosphorylation of just one residue, Y721, mediates association of PI3K with the receptor to activate the major motility signaling pathways in macrophages. Dissection of these pathways will identify drug targets for the inhibition of diseases in which macrophages contribute to adverse outcomes.
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308
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Lock FE, Ryan KR, Poulter NS, Parsons M, Hotchin NA. Differential regulation of adhesion complex turnover by ROCK1 and ROCK2. PLoS One 2012; 7:e31423. [PMID: 22348083 PMCID: PMC3278444 DOI: 10.1371/journal.pone.0031423] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Accepted: 01/07/2012] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND ROCK1 and ROCK2 are serine/threonine kinases that function downstream of the small GTP-binding protein RhoA. Rho signalling via ROCK regulates a number of cellular functions including organisation of the actin cytoskeleton, cell adhesion and cell migration. METHODOLOGY/PRINCIPAL FINDINGS In this study we use RNAi to specifically knockdown ROCK1 and ROCK2 and analyse their role in assembly of adhesion complexes in human epidermal keratinocytes. We observe that loss of ROCK1 inhibits signalling via focal adhesion kinase resulting in a failure of immature adhesion complexes to form mature stable focal adhesions. In contrast, loss of ROCK2 expression results in a significant reduction in adhesion complex turnover leading to formation of large, stable focal adhesions. Interestingly, loss of either ROCK1 or ROCK2 expression significantly impairs cell migration indicating both ROCK isoforms are required for normal keratinocyte migration. CONCLUSIONS ROCK1 and ROCK2 have distinct and separate roles in adhesion complex assembly and turnover in human epidermal keratinocytes.
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Affiliation(s)
- Frances E. Lock
- School of Biosciences, University of Birmingham, Edgbaston, United Kingdom
| | - Katie R. Ryan
- School of Biosciences, University of Birmingham, Edgbaston, United Kingdom
| | - Natalie S. Poulter
- School of Biosciences, University of Birmingham, Edgbaston, United Kingdom
| | - Maddy Parsons
- Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - Neil A. Hotchin
- School of Biosciences, University of Birmingham, Edgbaston, United Kingdom
- * E-mail:
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309
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Varicose veins: role of mechanotransduction of venous hypertension. Int J Vasc Med 2012; 2012:538627. [PMID: 22489273 PMCID: PMC3303599 DOI: 10.1155/2012/538627] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 11/13/2011] [Indexed: 11/17/2022] Open
Abstract
Varicose veins affect approximately one-third of the adult population and result in significant psychological, physical, and financial burden. Nevertheless, the molecular pathogenesis of varicose vein formation remains unidentified. Venous hypertension exerted on veins of the lower extremity is considered the principal factor in varicose vein formation. The role of mechanotransduction of the high venous pressure in the pathogenesis of varicose vein formation has not been adequately investigated despite a good progress in understanding the mechanomolecular mechanisms involved in transduction of high blood pressure in the arterial wall. Understanding the nature of the mechanical forces, the mechanosensors and mechanotransducers in the vein wall, and the downstream signaling pathways will provide new molecular targets for the prevention and treatment of varicose veins. This paper summarized the current understanding of mechano-molecular pathways involved in transduction of hemodynamic forces induced by blood pressure and tries to relate this information to setting of venous hypertension in varicose veins.
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310
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Suga K, Kondo S, Matsuura S, Kinoshita Y, Urushihara M, Kagami S. Glomerular expression of hydrogen peroxide-inducible clone-5 in human and rat progressive mesangial proliferative glomerulonephritis. Nephron Clin Pract 2012; 120:e59-68. [PMID: 22286178 DOI: 10.1159/000335780] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Accepted: 12/12/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS Hydrogen peroxide-inducible clone-5 (Hic-5) is a transforming growth factor-β(1) (TGF-β(1))- and hydrogen peroxide (H(2)O(2))-inducible focal adhesion protein that may be necessary for maintaining the myofibroblastic phenotype in pathological scar formation. To investigate the involvement of Hic-5 in the pathogenesis of glomerulonephritis (GN), we examined the glomerular expression of Hic-5 in human and rat GN as well as the regulation of Hic-5 by TGF-β(1) in vitro. METHODS AND RESULTS Immunohistochemical analyses showed that the expression of Hic-5 was increased in mesangial cells (MCs) in human mesangial proliferative GN. Hic-5 expression was significantly correlated not only with the levels of α-smooth muscle actin (α-SMA) and TGF-β(1), the accumulation of extracellular matrix, and the number of glomerular cells, but also with the urinary protein level in patients with GN. Glomerular Hic-5 expression increased in parallel with α-SMA expression in a rat model of mesangial proliferative GN. Combined therapy with an angiotensin type I receptor blocker and an antioxidant in this model improved the histology and the expression of Hic-5 and α-SMA. TGF-β(1) upregulated Hic-5 and α-SMA protein levels in human cultured MCs. CONCLUSION Our findings suggest that Hic-5 is involved in changes in the MC phenotype to produce abnormal extracellular matrix remodeling in GN.
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Affiliation(s)
- Kenichi Suga
- Department of Pediatrics, Institute of Health Bioscience, The University of Tokushima Graduate School, Tokushima, Japan
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311
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Fletcher SJ, Poulter NS, Haining EJ, Rappoport JZ. Clathrin-mediated endocytosis regulates occludin, and not focal adhesion, distribution during epithelial wound healing. Biol Cell 2012; 104:238-56. [DOI: 10.1111/boc.201100004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 12/14/2011] [Indexed: 01/28/2023]
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312
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Welf ES, Haugh JM. Stochastic models of cell protrusion arising from spatiotemporal signaling and adhesion dynamics. Methods Cell Biol 2012; 110:223-41. [PMID: 22482951 DOI: 10.1016/b978-0-12-388403-9.00009-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
During cell migration, local protrusion events are regulated by biochemical and physical processes that are in turn coordinated with the dynamic properties of cell-substratum adhesion structures. In this chapter, we present a modeling approach for integrating the apparent stochasticity and spatial dependence of signal transduction pathways that promote protrusion in tandem with adhesion dynamics. We describe our modeling framework, as well as its abstraction, parameterization, and validation against experimental data. Analytical techniques for identifying and evaluating the effects of model bistability on simulation simulation results are shown, and implications of this analysis for understanding cell protrusion behavior are offered.
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Affiliation(s)
- Erik S Welf
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina, USA
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313
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Abstract
Cell migration is required for many physiological processes, including wound repair and embryogenesis, and relies on precisely orchestrated events that are regulated in a spatially and temporally controlled manner. Most traditional approaches for studying migration, such as genetic methods or the use of chemical inhibitors, do not offer insight into these important components of protein function. However, chemical tools, which respond on a more rapid time scale and in localized regions of the cell, are capable of providing more detailed, real-time information. This Review describes these recent approaches to investigate cell migration and focuses on proteins that are activated by light or small molecules, as well as fluorescent sensors of protein activity.
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Affiliation(s)
- Brenda N. Goguen
- Departments of Biology and Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Barbara Imperiali
- Departments of Biology and Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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314
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Tyrosine phosphorylation of cortactin by the FAK-Src complex at focal adhesions regulates cell motility. BMC Cell Biol 2011; 12:49. [PMID: 22078467 PMCID: PMC3245448 DOI: 10.1186/1471-2121-12-49] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Accepted: 11/13/2011] [Indexed: 12/13/2022] Open
Abstract
Background Cell migration plays an important role in many physiological and pathological processes, including immune cell chemotaxis and cancer metastasis. It is a coordinated process that involves dynamic changes in the actin cytoskeleton and its interplay with focal adhesions. At the leading edge of a migrating cell, it is the re-arrangement of actin and its attachment to focal adhesions that generates the driving force necessary for movement. However, the mechanisms involved in the attachment of actin filaments to focal adhesions are still not fully understood. Results Signaling by the FAK-Src complex plays a crucial role in regulating the formation of protein complexes at focal adhesions to which the actin filaments are attached. Cortactin, an F-actin associated protein and a substrate of Src kinase, was found to interact with FAK through its SH3 domain and the C-terminal proline-rich regions of FAK. We found that the autophosphorylation of Tyr397 in FAK, which is necessary for FAK activation, was not required for the interaction with cortactin, but was essential for the tyrosine phosphorylation of the associated cortactin. At focal adhesions, cortactin was phosphorylated at tyrosine residues known to be phosphorylated by Src. The tyrosine phosphorylation of cortactin and its ability to associate with the actin cytoskeleton were required in tandem for the regulation of cell motility. Cell motility could be inhibited by truncating the N-terminal F-actin binding domains of cortactin or by blocking tyrosine phosphorylation (Y421/466/475/482F mutation). In addition, the mutant cortactin phosphorylation mimic (Y421/466/475/482E) had a reduced ability to interact with FAK and promoted cell motility. The promotion of cell motility by the cortactin phosphorylation mimic could also be inhibited by truncating its N-terminal F-actin binding domains. Conclusions Our results suggest that cortactin acts as a bridging molecule between actin filaments and focal adhesions. The cortactin N-terminus associates with F-actin, while its C-terminus interacts with focal adhesions. The tyrosine phosphorylation of cortactin by the FAK-Src complex modulates its interaction with FAK and increases its turnover at focal adhesions to promote cell motility.
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315
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Mace PD, Wallez Y, Dobaczewska MK, Lee JJ, Robinson H, Pasquale EB, Riedl SJ. NSP-Cas protein structures reveal a promiscuous interaction module in cell signaling. Nat Struct Mol Biol 2011; 18:1381-7. [PMID: 22081014 PMCID: PMC3230775 DOI: 10.1038/nsmb.2152] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Accepted: 08/30/2011] [Indexed: 12/16/2022]
Abstract
NSP and Cas family proteins form multidomain signaling platforms that mediate cell migration and invasion through a collection of distinct signaling motifs. Members of each family interact via their respective C-terminal domains, but the mechanism of this association has remained enigmatic. Here we present the crystal structures of the C-terminal domain from the human NSP protein BCAR3 and the complex of NSP3 with p130Cas. BCAR3 adopts the Cdc25-homology fold of Ras GTPase exchange factors, but exhibits a “closed” conformation incapable of enzymatic activity. The NSP3–p130Cas complex structure reveals that this closed conformation is instrumental for interaction of NSP proteins with a focal adhesion-targeting domain present in Cas proteins. This enzyme to adaptor conversion enables high affinity, yet promiscuous, interactions between NSP and Cas proteins and represents an unprecedented mechanistic paradigm linking cellular signaling networks.
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Affiliation(s)
- Peter D Mace
- Program of Apoptosis and Cell Death Research, Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California, USA
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316
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Gribben L, Baxter RC, Marsh DJ. Insulin-like growth factor binding protein-3 inhibits migration of endometrial cancer cells. Cancer Lett 2011; 317:41-8. [PMID: 22085490 DOI: 10.1016/j.canlet.2011.11.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2011] [Revised: 11/07/2011] [Accepted: 11/07/2011] [Indexed: 10/15/2022]
Abstract
Cell migration and invasion leading to metastasis is a major cause of death from endometrial cancer (EC). We have shown that the rate of EC cell migration is inversely related to the level of insulin-like growth factor protein-3 (IGFBP-3). Down-regulation of IGFBP-3 by siRNA in EC cells accelerated migration without affecting proliferation and cells displayed a more migratory phenotype, with co-localization of migration-associated markers at the leading edge of cell membranes. Opposite effects were seen with either the addition of recombinant IGFBP-3 or overexpression of IGFBP-3. Cells with mutated PTEN had the highest IGFBP-3 expression and the slowest migration rates. This study demonstrates that endogenous IGFBP-3 modulates adhesion-migration dynamics in EC cells, implying that it may be important in regulating metastasis in this disease.
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Affiliation(s)
- Lujia Gribben
- Hormones & Cancer Division, Kolling Institute of Medical Research, University of Sydney, Royal North Shore Hospital, St. Leonards, NSW 2065, Australia
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317
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Truttmann MC, Misselwitz B, Huser S, Hardt WD, Critchley DR, Dehio C. Bartonella henselae engages inside-out and outside-in signaling by integrin β1 and talin1 during invasome-mediated bacterial uptake. J Cell Sci 2011; 124:3591-602. [PMID: 22045736 DOI: 10.1242/jcs.084459] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The VirB/D4 type IV secretion system (T4SS) of the bacterial pathogen Bartonella henselae (Bhe) translocates seven effector proteins (BepA-BepG) into human cells that subvert host cellular functions. Two redundant pathways dependent on BepG or the combination of BepC and BepF trigger the formation of a bacterial uptake structure termed the invasome. Invasome formation is a multi-step process consisting of bacterial adherence, effector translocation, aggregation of bacteria on the cell surface and engulfment, and eventually, complete internalization of the bacterial aggregate occurs in an F-actin-dependent manner. In the present study, we show that Bhe-triggered invasome formation depends on integrin-β1-mediated signaling cascades that enable assembly of the F-actin invasome structure. We demonstrate that Bhe interacts with integrin β1 in a fibronectin- and VirB/D4 T4SS-independent manner and that activated integrin β1 is essential for both effector translocation and the actin rearrangements leading to invasome formation. Furthermore, we show that talin1, but not talin2, is required for inside-out activation of integrin β1 during invasome formation. Finally, integrin-β1-mediated outside-in signaling by FAK, Src, paxillin and vinculin is necessary for invasome formation. This is the first example of a bacterial entry process that fully exploits the bi-directional signaling capacity of integrin receptors in a talin1-specific manner.
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Affiliation(s)
- Matthias C Truttmann
- Focal Area Infection Biology, Biozentrum of the University of Basel, Klingelbergstr. 70, CH-4056 Basel, Switzerland
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318
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Sundd P, Gutierrez E, Petrich BG, Ginsberg MH, Groisman A, Ley K. Live cell imaging of paxillin in rolling neutrophils by dual-color quantitative dynamic footprinting. Microcirculation 2011; 18:361-72. [PMID: 21418380 DOI: 10.1111/j.1549-8719.2011.00090.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
OBJECTIVE Neutrophil recruitment to sites of inflammation involves P-selectin-dependent rolling. qDF is a useful tool to visualize the topography of the neutrophil footprint as it interacts with the substrate. However, elucidating the role of specific proteins in addition to topography requires simultaneous visualization of two fluorochromes. METHODS To validate DqDF, mouse neutrophils were labeled with the membrane dyes DiO and DiI and perfused into microchannels coated with P-selectin-Fc. Footprints of rolling neutrophils were recorded as two separate images, one for each fluorochrome. To assess the localization of the cytoskeletal protein paxillin, we applied DqDF to DiO-stained neutrophils of mice expressing an mCherry-paxillin fusion protein. RESULTS The footprint topographies obtained from DiO and DiI in the plasma membrane were identical. The z-coordinates of the microvilli tips obtained with the two fluorochromes in the footprint were also identical. Paxillin was found to be localized to some, but not all ridges in the neutrophil footprint. CONCLUSIONS Our data suggest that the spectral properties of the fluorochrome do not affect the results. DqDF will be useful for simultaneous visualization of two fluorochromes in the footprint of rolling cells.
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Affiliation(s)
- Prithu Sundd
- Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California, USA
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319
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Full activity of the deleted in liver cancer 1 (DLC1) tumor suppressor depends on an LD-like motif that binds talin and focal adhesion kinase (FAK). Proc Natl Acad Sci U S A 2011; 108:17129-34. [PMID: 21969587 DOI: 10.1073/pnas.1112122108] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The deleted in liver cancer 1 (DLC1) tumor suppressor gene, which is frequently inactivated in cancer, encodes a Rho-GAP (GTPase activating protein) focal adhesion protein whose negative regulation of Rho-GTPases is necessary but not sufficient for its full tumor suppressor activity. Here, we report that DLC1 forms a complex with two prooncogenic focal adhesion proteins, talin and the focal adhesion kinase (FAK). We identified an 8-aa sequence (residues 469LDDILYHV476) in DLC1 and designated it an LD-like motif, because it shares homology with the LD motifs of paxillin. This motif was necessary for DLC1 binding to talin and FAK, because a DLC1 mutant, from which six of the residues have been deleted, and another mutant carrying amino acid substitutions in three of the residues are deficient for binding both proteins and localization of DLC1 to focal adhesions. FAK binding was independent of talin and vice versa. In bioassays, both DLC1 mutants were less active than wild-type (WT) DLC1, although the ability of the mutants to negatively regulate overall Rho-GTP was not impaired. We conclude that the LD-like motif, which binds talin and FAK, is required for the full tumor suppressor activity of DLC1 and contributes to the association of DLC1 with focal adhesions.
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320
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Tabassam FH, Graham DY, Yamaoka Y. Paxillin is a novel cellular target for converging Helicobacter pylori-induced cellular signaling. Am J Physiol Gastrointest Liver Physiol 2011; 301:G601-11. [PMID: 21757638 PMCID: PMC3191551 DOI: 10.1152/ajpgi.00375.2010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Paxillin is involved in the regulation of Helicobacter pylori-mediated gastric epithelial cell motility. We investigated the signaling pathways regulating H. pylori-induced paxillin phosphorylation and the effect of the H. pylori virulence factors cag pathogenicity island (PAI) and outer inflammatory protein (OipA) on actin stress fiber formation, cell phenotype, and IL-8 production. Gastric cell infection with live H. pylori induced site-specific phosphorylation of paxillin tyrosine (Y) 31 and Y118 in a time- and concentration-dependent manner. Activated paxillin localized in the cytoplasm at the tips of H. pylori-induced actin stress fibers. Isogenic oipA mutants significantly reduced paxillin phosphorylation at Y31 and Y118 and reduced actin stress fiber formation. In contrast, cag PAI mutants only inhibited paxillin Y118 phosphorylation. Silencing of epidermal growth factor receptor (EGFR), focal adhesion kinase (FAK), or protein kinase B (Akt) expression by small-interfering RNAs or inhibiting kinase activity of EGFR, Src, or phosphatidylinositol 3-kinase (PI3K) markedly reduced H. pylori-induced paxillin phosphorylation and morphologic alterations. Reduced FAK expression or lack of Src kinase activity suppressed H. pylori-induced IL-8 production. Compared with infection with the wild type, infection with the cag PAI mutant and oipA mutant reduced IL-8 production by nearly 80 and 50%. OipA-induced IL-8 production was FAK- and Src-dependent, although a FAK/Src-independent pathway for IL-8 production also exists, and the cag PAI may be mainly involved in this pathway. We propose paxillin as a novel cellular target for converging H. pylori-induced EGFR, FAK/Src, and PI3K/Akt signaling to regulate cytoskeletal reorganization and IL-8 production in part, thus contributing to the H. pylori-induced diseases.
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Affiliation(s)
- Fazal H. Tabassam
- 1Department of Medicine/Gastroenterology, Michael E. DeBakey Veterans Affairs Medical Center and Baylor College of Medicine, Houston, Texas; and
| | - David Y. Graham
- 1Department of Medicine/Gastroenterology, Michael E. DeBakey Veterans Affairs Medical Center and Baylor College of Medicine, Houston, Texas; and
| | - Yoshio Yamaoka
- 1Department of Medicine/Gastroenterology, Michael E. DeBakey Veterans Affairs Medical Center and Baylor College of Medicine, Houston, Texas; and ,2Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Yufu, Oita, Japan
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321
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Abstract
Most experiments observing cell migration use planar plastic or glass surfaces despite these conditions being considerably different from physiological ones. On such planar surfaces, cells take a dorsal-ventral polarity to move two-dimensionally. Cells in tissues, however, interact with surrounding cells and the extracellular matrix such that they transverse three-dimensionally. For this reason, three-dimensional matrices have become more and more popular for cell migration experiments. In addition, recent developments in imaging techniques have enabled high resolution observations of in vivo cell migration. The combination of three-dimensional matrices and such imaging techniques has revealed motile mechanisms in tissues not observable in studies using planar surfaces. Regarding models for such cell migration studies, the cellular slime mould Dictyostelium discoideum is ideal. Single amoeboid cells aggregate into hemispherical mound structures upon starvation to begin a multicellular morphogenesis. These tiny and simple multicellular bodies are suitable for observing the behaviors of individual cells in multicellular structures. Furthermore, the unique life cycle can be exploited to identify which genes are involved in cell migration in multicellular environments. Since mutants lacking such genes are expected to fail to undergo morphogenesis, easy and systematic gene screening is possible by isolating mutants whose developments arrest around the mound stage, which is the case for several mutants lacking specific cytoskeletal proteins. In this article, I discuss the basic elements required for cell migration in multicellular environments and how Dictyostelium can be used to elucidate them.
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Affiliation(s)
- Masatsune Tsujioka
- Special Research Promotion Group, Graduate School of Frontier Bioscience, Osaka University, 1-3 Yamadaoka, Suita, Japan.
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322
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Wade R, Brimer N, Lyons C, Pol SV. Paxillin enables attachment-independent tyrosine phosphorylation of focal adhesion kinase and transformation by RAS. J Biol Chem 2011; 286:37932-37944. [PMID: 21900245 DOI: 10.1074/jbc.m111.294504] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Paxillin and HIC5 are closely related adapter proteins that regulate cell migration and are tyrosine-phosphorylated by focal adhesion kinase (FAK). Paxillin, HIC5, and FAK tyrosine phosphorylation increase upon cell attachment and decrease upon detachment from extracellular matrix. Unexpectedly, we found that although FAK tyrosine phosphorylation in attached cells did not require paxillin, in detached fibroblasts there was remaining FAK tyrosine phosphorylation that required expression of paxillin and was not supported by HIC5. The support of attachment-independent FAK tyrosine phosphorylation required the paxillin LIM domains and suggested that paxillin might facilitate oncogenic transformation. Paxillin but not HIC5 augmented anchorage-independent cell proliferation induced by RAS. Both anchorage-independent FAK tyrosine phosphorylation and RAS-induced colony formation required multiple docking sites on paxillin, including LD4 (docking sites for FAK-Src and GIT1/2-PIX-NCK-PAK complex), LD5, and all four carboxyl-terminal LIM domains (that bind tubulin and PTP-PEST). Analysis using paxillin mutants dissociated domains of paxillin that are required for regulation of cell migration from domains that are required for anchorage-independent cell proliferation and demonstrated essential functions of the paxillin LIM domains that are not found in HIC5 LIM domains. These results highlight the role of paxillin in facilitating attachment-independent signal transduction implicated in cancer.
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Affiliation(s)
- Ramon Wade
- Department of Pathology, University of Virginia, Charlottesville, Virginia 22908
| | - Nicole Brimer
- Department of Pathology, University of Virginia, Charlottesville, Virginia 22908
| | - Charles Lyons
- Department of Pathology, University of Virginia, Charlottesville, Virginia 22908
| | - Scott Vande Pol
- Department of Pathology, University of Virginia, Charlottesville, Virginia 22908.
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323
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Fujikawa A, Fukada M, Makioka Y, Suzuki R, Chow JPH, Matsumoto M, Noda M. Consensus substrate sequence for protein-tyrosine phosphatase receptor type Z. J Biol Chem 2011; 286:37137-46. [PMID: 21890632 DOI: 10.1074/jbc.m111.270140] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein-tyrosine phosphatase receptor type Z (Ptprz) has multiple substrate proteins, including G protein-coupled receptor kinase-interactor 1 (Git1), membrane-associated guanylate kinase, WW and PDZ domain-containing 1 (Magi1), and GTPase-activating protein for Rho GTPase (p190RhoGAP). We have identified a dephosphorylation site at Tyr-1105 of p190RhoGAP; however, the structural determinants employed for substrate recognition of Ptprz have not been fully defined. In the present study, we revealed that Ptprz selectively dephosphorylates Git1 at Tyr-554, and Magi1 at Tyr-373 and Tyr-858 by in vitro and cell-based assays. Of note, the dephosphorylation of the Magi1 Tyr-858 site required PDZ domain-mediated interaction between Magi1 and Ptprz in the cellular context. Alignment of the primary sequences surrounding the target phosphotyrosine residue in these three substrates showed considerable similarity, suggesting a consensus motif for recognition by Ptprz. We then estimated the contribution of surrounding individual amino acid side chains to the catalytic efficiency by using fluorescent peptides based on the Git1 Tyr-554 sequence in vitro. The typical substrate motif for the catalytic domain of Ptprz was deduced to be Glu/Asp-Glu/Asp-Glu/Asp-Xaa-Ile/Val-Tyr(P)-Xaa (Xaa is not an acidic residue). Intriguingly, a G854D substitution of the Magi1 Tyr-858 site matching better to the motif sequence turned this site to be susceptible to dephosphorylation by Ptprz independent of the PDZ domain-mediated interaction in cells. Furthermore, we found by database screening that the substrate motif is present in several proteins, including paxillin at Tyr-118, its major phosphorylation site. Expectedly, we verified that Ptprz efficiently dephosphorylates paxillin at this site in cells. Our study thus provides key insights into the molecular basis for the substrate recognition of Ptprz.
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Affiliation(s)
- Akihiro Fujikawa
- Division of Molecular Neurobiology, National Institute for Basic Biology, The Graduate University for Advanced Studies, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi 444-8787, Japan
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324
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Athanasopoulou A, Aroukatos P, Nakas D, Repanti M, Papadaki H, Bravou V. Decreased ezrin and paxillin expression in human urothelial bladder tumors correlate with tumor progression. Urol Oncol 2011; 31:836-42. [PMID: 21868260 DOI: 10.1016/j.urolonc.2011.07.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 06/29/2011] [Accepted: 07/07/2011] [Indexed: 12/01/2022]
Abstract
OBJECTIVES F-actin binding proteins ezrin and paxillin are involved in cell adhesion and cell migration/invasion. The aim of the study was to investigate their role in urothelial bladder carcinogenesis. MATERIALS AND METHODS Expression of ezrin and paxillin was studied by immunohistochemistry in 104 and 96 cases of urothelial bladder tumors, respectively. Correlations with clinicopathologic data and expression of p53, E-cadherin, and β-catenin were examined. RESULTS Positive ezrin and paxillin protein expression was found in 99% and 93.7% of cases, respectively. Membranous expression of ezrin was significantly lower in high grade tumors and correlated with invasion. Multivariate analysis showed that ezrin is an independent predictor of muscularis propria invasion. Paxillin expression was significantly decreased in urothelial carcinomas compared with tumors of low malignant potential and low paxillin levels also correlated with advancing tumor stage and invasion. A statistically significant correlation was found between membranous ezrin and E-cadherin as well as between ezrin and paxillin expression in urothelial tumors. CONCLUSIONS Down-regulation of ezrin and paxillin in urothelial bladder tumors is associated with aggressive tumor features and invasiveness.
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Affiliation(s)
- Afrodite Athanasopoulou
- Department of Anatomy-Histology-Embryology, School of Medicine, University of Patras, Patras, Greece
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325
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Wu Y, He L, Zhang L, Chen J, Yi Z, Zhang J, Liu M, Pang X. Anacardic Acid (6-Pentadecylsalicylic Acid) Inhibits Tumor Angiogenesis by Targeting Src/FAK/Rho GTPases Signaling Pathway. J Pharmacol Exp Ther 2011; 339:403-11. [DOI: 10.1124/jpet.111.181891] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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326
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Germano S, Kennedy S, Rani S, Gleeson G, Clynes M, Doolan P, McDonnell S, Hughes L, Crown J, O'Driscoll L. MAGE-D4B is a novel marker of poor prognosis and potential therapeutic target involved in breast cancer tumorigenesis. Int J Cancer 2011; 130:1991-2002. [PMID: 21618523 DOI: 10.1002/ijc.26200] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2010] [Accepted: 05/02/2011] [Indexed: 11/07/2022]
Abstract
Melanoma-associated antigen (MAGE) family members are generally described as tumor-specific antigens. An association between MAGE-D4B and breast cancer has yet to be reported and the functional role of the encoded protein has never been established. We performed microarray analysis of 104 invasive breast tumors and matched non-cancerous breast biopsies. qPCR was used for validation in an independent biobank. To investigate the biological relevance of MAGE-D4B in breast tumorigenesis, its phenotypic effects were assessed in vitro. Overall, MAGE-D4B was detected in 43% of tumors while undetected in normal breast tissue. MAGE-D4B was found to correlate with tumor progression and to be an independent prognostic marker for poor outcome in term of relapse-free and overall survival, with potential predictive relevance in relation to response to chemotherapy. RNA interference-mediated knockdown of MAGE-D4B significantly hampered the invasive properties of Hs578T cells by affecting anchorage-independent growth, adhesion, migration and invasion affecting anchorage-independent growth, adhesion, migration and invasion and by modulating expression of invasion-suppressor gene E-cadherin.
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Affiliation(s)
- Serena Germano
- School of Pharmacy and Pharmaceutical Sciences, Trinity College Dublin, Dublin, Ireland
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327
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Hsu WM, Che MI, Liao YF, Chang HH, Chen CH, Huang YM, Jeng YM, Huang J, Quon MJ, Lee H, Huang HC, Huang MC. B4GALNT3 expression predicts a favorable prognosis and suppresses cell migration and invasion via β₁ integrin signaling in neuroblastoma. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 179:1394-404. [PMID: 21741930 DOI: 10.1016/j.ajpath.2011.05.025] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2010] [Revised: 05/03/2011] [Accepted: 05/09/2011] [Indexed: 01/20/2023]
Abstract
β1,4-N-acetylgalactosaminyltransferase III (B4GALNT3) promotes the formation of GalNAcβ1,4GlcNAc (LacdiNAc or LDN). Drosophila β1,4-N-acetylgalactosaminyltransferase A (B4GALNTA) contributes to the synthesis of LDN, which helps regulate neuronal development. In this study, we investigated the expression and role of B4GALNT3 in human neuroblastoma (NB). We used IHC analysis to examine 87 NB tumors, and we identified correlations between B4GALNT3 expression and clinicopathologic factors, including patient survival. Effects of recombinant B4GALNT3 on cell behavior and signaling were studied in SK-N-SH and SH-SY5Y NB cells. Increased expression of B4GALNT3 in NB tumors correlated with a favorable histologic profile (P < 0.001, χ² test) and early clinical staging (P = 0.041, χ² test) and was a favorable prognostic factor for survival as evaluated by univariate and multivariate analyses. Reexpression of B4GALNT3 in SK-N-SH and SH-SY5Y cells suppressed cell proliferation, colony formation, migration, and invasion. Moreover, B4GALNT3 increased the LacdiNAc modification of β₁ integrin, leading to decreased phosphorylation of focal adhesion kinase (FAK), Src, paxillin, Akt, and ERK1/2. B4GALNT3-mediated suppression of cell migration and invasion were substantially reversed by concomitant expression of constitutively active Akt or MEK. We conclude that B4GALNT3 predicts a favorable prognosis for NB and suppresses the malignant phenotype via decreasing β₁ integrin signaling.
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Affiliation(s)
- Wen-Ming Hsu
- Department of Surgery, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
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328
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Lu D, Kassab GS. Role of shear stress and stretch in vascular mechanobiology. J R Soc Interface 2011; 8:1379-85. [PMID: 21733876 DOI: 10.1098/rsif.2011.0177] [Citation(s) in RCA: 179] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Blood vessels are under constant mechanical loading from blood pressure and flow which cause internal stresses (endothelial shear stress and circumferential wall stress, respectively). The mechanical forces not only cause morphological changes of endothelium and blood vessel wall, but also trigger biochemical and biological events. There is considerable evidence that physiologic stresses and strains (stretch) exert vasoprotective roles via nitric oxide and provide a homeostatic oxidative balance. A perturbation of tissue stresses and strains can disturb biochemical homeostasis and lead to vascular remodelling and possible dysfunction (e.g. altered vasorelaxation, tone, stiffness, etc.). These distinct biological endpoints are caused by some common biochemical pathways. The focus of this brief review is to point out some possible commonalities in the molecular pathways in response to endothelial shear stress and circumferential wall stretch.
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Affiliation(s)
- Deshun Lu
- Department of Biomedical Engineering, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA
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329
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Deakin NO, Turner CE. Distinct roles for paxillin and Hic-5 in regulating breast cancer cell morphology, invasion, and metastasis. Mol Biol Cell 2011; 22:327-41. [PMID: 21148292 PMCID: PMC3031464 DOI: 10.1091/mbc.e10-09-0790] [Citation(s) in RCA: 136] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
This study reveals novel roles for the focal adhesion proteins paxillin and Hic-5 in regulating breast cancer invasion strategies and metastasis. Depletion of paxillin promotes a hypermesenchymal phenotype while dysregulating 3D adhesion dynamics. In contrast, RNAi of Hic-5 induces a hyperamoeboid phenotype with dysregulated RhoA/pMLC signaling. Individual metastatic tumor cells exhibit two interconvertible modes of cell motility during tissue invasion that are classified as either mesenchymal or amoeboid. The molecular mechanisms by which invasive breast cancer cells regulate this migratory plasticity have yet to be fully elucidated. Herein we show that the focal adhesion adaptor protein, paxillin, and the closely related Hic-5 have distinct and unique roles in the regulation of breast cancer cell lung metastasis by modulating cell morphology and cell invasion through three-dimensional extracellular matrices (3D ECMs). Cells depleted of paxillin by RNA interference displayed a highly elongated mesenchymal morphology, whereas Hic-5 knockdown induced an amoeboid phenotype with both cell populations exhibiting reduced plasticity, migration persistence, and velocity through 3D ECM environments. In evaluating associated signaling pathways, we determined that Rac1 activity was increased in cells devoid of paxillin whereas Hic-5 silencing resulted in elevated RhoA activity and associated Rho kinase–induced nonmuscle myosin II activity. Hic-5 was essential for adhesion formation in 3D ECMs, and analysis of adhesion dynamics and lifetime identified paxillin as a key regulator of 3D adhesion assembly, stabilization, and disassembly.
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Affiliation(s)
- Nicholas O Deakin
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA
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330
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Matsuura S, Kondo S, Suga K, Kinoshita Y, Urushihara M, Kagami S. Expression of focal adhesion proteins in the developing rat kidney. J Histochem Cytochem 2011; 59:864-74. [PMID: 21705647 DOI: 10.1369/0022155411413929] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Focal adhesions play a critical role as centers that transduce signals by cell-matrix interactions and regulate fundamental processes such as proliferation, migration, and differentiation. Focal adhesion kinase (FAK), paxillin, integrin-linked kinase (ILK), and hydrogen peroxide-inducible clone-5 (Hic-5) are major proteins that contribute to these events. In this study, we investigated the expression of focal adhesion proteins in the developing rat kidney. Western blotting analysis revealed that the protein levels of FAK, p-FAK(397), paxillin, p-paxillin(118), and Hic-5 were high in embryonic kidneys, while ILK expression persisted from the embryonic to the mature stage. Immunohistochemistry revealed that FAK, p-FAK(397), paxillin, and p-paxillin(118) were strongly expressed in condensed mesenchymal cells and the ureteric bud. They were detected in elongating tubules and immature glomerular cells in the nephrogenic zone. Hic-5 was predominantly expressed in mesenchymal cells as well as immature glomerular endothelial and mesangial cells, suggesting that Hic-5 might be involved in mesenchymal cell development. ILK expression was similar to that of FAK in the developmental stages. Interestingly, ILK was strongly expressed in podocytes in mature glomeruli. ILK might play a role in epithelial cell differentiation as well as kidney growth and morphogenesis. In conclusion, the temporospatially regulated expression of focal adhesion proteins during kidney development might play a role in morphogenesis and cell differentiation.
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Affiliation(s)
- Sato Matsuura
- Department of Pediatrics, Institute of Health Bioscience, The University of Tokushima Graduate School, Tokushima, Japan
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331
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Importin alpha-mediated nuclear import of cytoplasmic poly(A) binding protein occurs as a direct consequence of cytoplasmic mRNA depletion. Mol Cell Biol 2011; 31:3113-25. [PMID: 21646427 DOI: 10.1128/mcb.05402-11] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Recent studies have found the cytoplasmic poly(A) binding protein (PABPC) to have opposing effects on gene expression when concentrated in the cytoplasm versus in the nucleus. PABPC is predominantly cytoplasmic at steady state, where it enhances protein synthesis through simultaneous interactions with mRNA and translation factors. However, it accumulates dramatically within the nucleus in response to various pathogenic and nonpathogenic stresses, leading to an inhibition of mRNA export. The molecular events that trigger relocalization of PABPC and the mechanisms by which it translocates into the nucleus to block gene expression are not understood. Here, we reveal an RNA-based mechanism of retaining PABPC in the cytoplasm. Expression either of viral proteins that promote mRNA turnover or of a cytoplasmic deadenylase drives nuclear relocalization of PABPC in a manner dependent on the PABPC RNA recognition motifs (RRMs). Using multiple independent binding sites within its RRMs, PABPC interacts with importin α, a component of the classical import pathway. Finally, we demonstrate that the direct association of PABPC with importin α is antagonized by the presence of poly(A) RNA, supporting a model in which RNA binding masks nuclear import signals within the PABPC RRMs, thereby ensuring efficient cytoplasmic retention of this protein in normal cells. These findings further suggest that cells must carefully calibrate the ratio of PABPC to mRNA, as events that offset this balance can dramatically influence gene expression.
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332
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Warner A, Qadota H, Benian GM, Vogl AW, Moerman DG. The Caenorhabditis elegans paxillin orthologue, PXL-1, is required for pharyngeal muscle contraction and for viability. Mol Biol Cell 2011; 22:2551-63. [PMID: 21633109 PMCID: PMC3135480 DOI: 10.1091/mbc.e10-12-0941] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Caenorhabditis elegans pxl-1 is the orthologue of vertebrate paxillin and is expressed in body wall and pharyngeal muscle. In body wall muscle PXL-1 localizes to dense bodies, M-lines, and adhesion plaques, and in pharyngeal muscle PXL-1 localizes to podosome-like actin attachment complexes. PXL-1 is required in the pharynx for muscle contraction and viability. We have identified the gene C28H8.6 (pxl-1) as the Caenorhabditis elegans orthologue of vertebrate paxillin. PXL-1 contains the four C-terminal LIM domains conserved in paxillin across all species and three of the five LD motifs found in the N-terminal half of most paxillins. In body wall muscle, PXL-1 antibodies and a full-length green fluorescent protein translational fusion localize to adhesion sites in the sarcomere, the functional repeat unit in muscle responsible for contraction. PXL-1 also localizes to ring-shaped structures near the sarcolemma in pharyngeal muscle corresponding to podosome-like sites of actin attachment. Our analysis of a loss-of-function allele of pxl-1, ok1483, shows that loss of paxillin leads to early larval arrested animals with paralyzed pharyngeal muscles and eventual lethality, presumably due to an inability to feed. We rescued the mutant phenotype by expressing paxillin solely in the pharynx and found that these animals survived and are essentially wild type in movement and body wall muscle structure. This indicates a differential requirement for paxillin in these two types of muscle. In pharyngeal muscle it is essential for contraction, whereas in body wall muscle it is dispensable for filament assembly, sarcomere stability, and ultimately movement.
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Affiliation(s)
- Adam Warner
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
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333
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Shi Z, Liu Y, Johnson JJ, Stack MS. Urinary-type plasminogen activator receptor (uPAR) modulates oral cancer cell behavior with alteration in p130cas. Mol Cell Biochem 2011; 357:151-61. [PMID: 21630091 DOI: 10.1007/s11010-011-0885-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2011] [Accepted: 05/17/2011] [Indexed: 12/24/2022]
Abstract
Oral cavity cancer is among the most frequently diagnosed cancers worldwide and urinary-type plasminogen activator receptor (uPAR) is clinically associated with more invasive tumors and enhanced lymph node metastasis. We seek to further elucidate the mechanism of by which uPAR promotes cell aggressiveness in the unique context of oral squamous cell carcinoma (OSCC). The contribution of uPAR expression to aggressive cellular behavior of OSCC was examined using in vitro cellular models wherein the expression of uPAR was manipulated and in a human OSCC tissue microarray. Results show altered adhesion, motility, and invasion in cells that overexpress uPAR relative to vector control cells. Distinct alterations of focal adhesion protein expression and phosphorylation, including p130cas and paxillin were observed, suggestive of enhanced focal adhesion turnover. Immunohistochemical analysis of microarrayed human OSCC revealed a significant correlation between uPAR and p130cas expression. The non-receptor protein tyrosine kinase c-Src was responsible for the phosphorylation of p130cas in response to uPAR/α3β1/laminin-5 engagement. Further downstream, the Rho family GTPase Cdc42, but not Rac1, was activated, suggesting a pathway leading to actin reorganization, filopodial protrusion and enhanced motility in uPAR overexpressing oral cancer cells. These data shed light on a molecular mechanism whereby acquisition of uPAR expression may modulate OSCC invasive activity through alteration of focal adhesion dynamics.
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Affiliation(s)
- Zonggao Shi
- Department of Pathology and Anatomical Sciences, University of Missouri School of Medicine, Columbia, MO 65212, USA.
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334
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Li X, Ji W, Zhang R, Folta-Stogniew E, Min W, Boggon TJ. Molecular recognition of leucine-aspartate repeat (LD) motifs by the focal adhesion targeting homology domain of cerebral cavernous malformation 3 (CCM3). J Biol Chem 2011; 286:26138-47. [PMID: 21632544 DOI: 10.1074/jbc.m110.211250] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cerebral cavernous malformation (CCM) is a disease that affects between 0.1 and 0.5% of the human population, with mutations in CCM3 accounting for ~ 15% of the autosomal dominant form of the disease. We recently reported that CCM3 contains an N-terminal dimerization domain (CCM3D) and a C-terminal focal adhesion targeting (FAT) homology domain. Intermolecular protein-protein interactions of CCM3 are mediated by a highly conserved surface on the FAT homology domain and are affected by CCM3 truncations in the human disease. Here we report the crystal structures of CCM3 in complex with three different leucine-aspartate repeat (LD) motifs (LD1, LD2, and LD4) from the scaffolding protein paxillin, at 2.8, 2.7, and 2.5 Å resolution. We show that CCM3 binds LD motifs using the highly conserved hydrophobic patch 1 (HP1) and that this binding is similar to the binding of focal adhesion kinase and Pyk2 FAT domains to paxillin LD motifs. We further show by surface plasmon resonance that CCM3 binds paxillin LD motifs with affinities in the micromolar range, similar to FAK family FAT domains. Finally, we show that endogenous CCM3 and paxillin co-localize in mouse cerebral pericytes. These studies provide a molecular-level framework to investigate the protein-protein interactions of CCM3.
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Affiliation(s)
- Xiaofeng Li
- Department of Pharmacology, Yale University School ofMedicine, New Haven, Connecticut 06520, USA
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335
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NF-κB mediates the 12(S)-HETE-induced endothelial to mesenchymal transition of lymphendothelial cells during the intravasation of breast carcinoma cells. Br J Cancer 2011; 105:263-71. [PMID: 21629247 PMCID: PMC3142797 DOI: 10.1038/bjc.2011.194] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Background: The intravasation of breast cancer into the lymphendothelium is an early step of metastasis. Little is known about the mechanisms of bulky cancer invasion into lymph ducts. Methods: To particularly address this issue, we developed a 3-dimensional co-culture model involving MCF-7 breast cancer cell spheroids and telomerase-immortalised human lymphendothelial cell (LEC) monolayers, which resembles intravasation in vivo and correlated the malignant phenotype with specific protein expression of LECs. Results: We show that tumour spheroids generate ‘circular chemorepellent-induced defects’ (CCID) in LEC monolayers through retraction of LECs, which was induced by 12(S)-hydroxyeicosatetraenoic acid (HETE) secreted by MCF-7 spheroids. This 12(S)-HETE-regulated retraction of LECs during intravasation particularly allowed us to investigate the key regulators involved in the motility and plasticity of LECs. In all, 12(S)-HETE induced pro-metastatic protein expression patterns and showed NF-κB-dependent up-regulation of the mesenchymal marker protein S100A4 and of transcriptional repressor ZEB1 concomittant with down-regulation of the endothelial adherence junction component VE-cadherin. This was in accordance with ∼50% attenuation of CCID formation by treatment of cells with 10 μM Bay11-7082. Notably, 12(S)-HETE-induced VE-cadherin repression was regulated by either NF-κB or by ZEB1 since ZEB1 siRNA knockdown abrogated not only 12(S)-HETE-mediated VE-cadherin repression but inhibited VE-cadherin expression in general. Interpretation: These data suggest an endothelial to mesenchymal transition-like process of LECs, which induces single cell motility during endothelial transmigration of breast carcinoma cells. In conclusion, this study demonstrates that the 12(S)-HETE-induced intravasation of MCF-7 spheroids through LECs require an NF-κB-dependent process of LECs triggering the disintegration of cell–cell contacts, migration, and the generation of CCID.
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336
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Choi CK, Zareno J, Digman MA, Gratton E, Horwitz AR. Cross-correlated fluctuation analysis reveals phosphorylation-regulated paxillin-FAK complexes in nascent adhesions. Biophys J 2011; 100:583-592. [PMID: 21281572 DOI: 10.1016/j.bpj.2010.12.3719] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Revised: 11/16/2010] [Accepted: 12/13/2010] [Indexed: 11/17/2022] Open
Abstract
We used correlation methods to detect and quantify interactions between paxillin and focal adhesion kinase (FAK) in migrating cells. Cross-correlation raster-scan image correlation spectroscopy revealed that wild-type paxillin and the phosphorylation-inhibiting paxillin mutant Y31F-Y118F do not interact with FAK in the cytosol but a phosphomimetic mutant of paxillin, Y31E-Y118E, does. By extending cross-correlation number and brightness analysis to the total internal reflection fluorescence modality, we were able to show that tetramers of paxillin and FAK form complexes in nascent adhesions with a 1:1 stoichiometry ratio. The phosphomimetic mutations on paxillin increase the size of the complex and the assembly rate of nascent adhesions, suggesting that the physical molecular aggregation of paxillin and FAK regulates adhesion formation. In contrast, when phosphorylation is inhibited, the interaction decreases and the adhesions tend to elongate rather than turn over. These direct in vivo data show that the phosphorylation of paxillin is specific to adhesions and leads to localized complex formation with FAK to regulate the dynamics of nascent adhesions.
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Affiliation(s)
- Colin K Choi
- Department of Cell Biology, University of Virginia, Charlottesville, Virginia.
| | - Jessica Zareno
- Department of Cell Biology, University of Virginia, Charlottesville, Virginia
| | - Michelle A Digman
- Laboratory of Fluorescence Dynamics, University of California, Irvine, California; Department of Biomedical Engineering, University of California, Irvine, California
| | - Enrico Gratton
- Laboratory of Fluorescence Dynamics, University of California, Irvine, California; Department of Biomedical Engineering, University of California, Irvine, California
| | - Alan Rick Horwitz
- Department of Cell Biology, University of Virginia, Charlottesville, Virginia
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337
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The role of β3-integrins in tumor angiogenesis: context is everything. Curr Opin Cell Biol 2011; 23:630-7. [PMID: 21565482 DOI: 10.1016/j.ceb.2011.03.014] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Accepted: 03/26/2011] [Indexed: 02/07/2023]
Abstract
Integrins are a family of cell-extracellular matrix adhesion molecules that play important roles in tumor angiogenesis. αvβ3-Integrin has received much attention as a potential anti-angiogenic target because it is upregulated in tumor-associated blood vessels. Agents targeting αvβ3-integrin are now showing some success in phase III clinical trails for the treatment of glioblastoma, but the exact function of this integrin in tumor angiogenesis is still relatively unknown. This review highlights some of the recent data illustrating that β3-integrins play both pro-angiogenic and anti-angiogenic roles in tumor angiogenesis depending on the context. Specifically we will discuss how the following differentially influence β3-integrin's role in tumor angiogenesis: first, cell-matrix interactions, second, β3-integrin inhibitor doses, third, cell type, and fourth, other interacting molecules.
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338
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Rooney N, Streuli CH. How integrins control mammary epithelial differentiation: a possible role for the ILK-PINCH-Parvin complex. FEBS Lett 2011; 585:1663-72. [PMID: 21570968 DOI: 10.1016/j.febslet.2011.05.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 05/05/2011] [Accepted: 05/05/2011] [Indexed: 01/15/2023]
Abstract
Differentiation into tissue-specific cell types occurs in response to numerous external signals. Integrins impart signals from the extracellular matrix microenvironment that are required for cell differentiation. However, the precise cytoplasmic transducers of these signals are yet to be understood properly. In lactating mammary epithelial cells, integrin-linked kinase has been identified as an indispensable integrin-signalling adaptor that enables the activation of Rac1, which is necessary for prolactin-induced milk protein expression. Here we use examples from various tissues to summarise possible mechanisms by which ILK and its binding partners PINCH and Parvin (ILK-PINCH-Parvin complex) could be required for Rac activation and mammary epithelial differentiation.
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Affiliation(s)
- Nicholas Rooney
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences and Manchester Breast Centre, University of Manchester, Manchester, UK
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339
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Ding VMY, Boersema PJ, Foong LY, Preisinger C, Koh G, Natarajan S, Lee DY, Boekhorst J, Snel B, Lemeer S, Heck AJR, Choo A. Tyrosine phosphorylation profiling in FGF-2 stimulated human embryonic stem cells. PLoS One 2011; 6:e17538. [PMID: 21437283 PMCID: PMC3060089 DOI: 10.1371/journal.pone.0017538] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Accepted: 02/08/2011] [Indexed: 01/05/2023] Open
Abstract
The role of fibroblast growth factor-2 (FGF-2) in maintaining undifferentiated human embryonic stem cells (hESC) was investigated using a targeted phosphoproteomics approach to specifically profile tyrosine phosphorylation events following FGF-2 stimulation. A cumulative total number of 735 unique tyrosine phosphorylation sites on 430 proteins were identified, by far the largest inventory to date for hESC. Early signaling events in FGF-2 stimulated hESC were quantitatively monitored using stable isotope dimethyl labeling, resulting in temporal tyrosine phosphorylation profiles of 316 unique phosphotyrosine peptides originating from 188 proteins. Apart from the rapid activation of all four FGF receptors, trans-activation of several other receptor tyrosine kinases (RTKs) was observed as well as induced tyrosine phosphorylation of downstream proteins such as PI3-K, MAPK and several Src family members. Both PI3-K and MAPK have been linked to hESC maintenance through FGF-2 mediated signaling. The observed activation of the Src kinase family members by FGF-2 and loss of pluripotent marker expression post Src kinase inhibition may point to the regulation of cytoskeletal and actin depending processes to maintain undifferentiated hESC.
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Affiliation(s)
- Vanessa M. Y. Ding
- Stem Cell Group, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Centre for Life Sciences (CeLS), NUS Graduate School for Integrative Sciences and Engineering (NGS), Singapore, Singapore
| | - Paul J. Boersema
- Biomolecular Mass Spectrometry and Proteomics Group, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
- Netherlands Proteomics Centre, Utrecht, The Netherlands
| | - Leong Yan Foong
- Stem Cell Group, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Christian Preisinger
- Biomolecular Mass Spectrometry and Proteomics Group, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
- Netherlands Proteomics Centre, Utrecht, The Netherlands
| | - Geoffrey Koh
- Stem Cell Group, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Subaashini Natarajan
- Stem Cell Group, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Dong-Yup Lee
- Stem Cell Group, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Centre for Life Sciences (CeLS), NUS Graduate School for Integrative Sciences and Engineering (NGS), Singapore, Singapore
| | - Jos Boekhorst
- Bioinformatics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Berend Snel
- Bioinformatics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Simone Lemeer
- Biomolecular Mass Spectrometry and Proteomics Group, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
- Netherlands Proteomics Centre, Utrecht, The Netherlands
| | - Albert J. R. Heck
- Biomolecular Mass Spectrometry and Proteomics Group, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
- Netherlands Proteomics Centre, Utrecht, The Netherlands
- Centre for Biomedical Genetics, Utrecht, The Netherlands
- * E-mail: (AC); (AJRH)
| | - Andre Choo
- Stem Cell Group, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Bioinformatics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
- Division of Bioengineering, Faculty of Engineering, National University of Singapore, Singapore, Singapore
- * E-mail: (AC); (AJRH)
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Matallanas D, Birtwistle M, Romano D, Zebisch A, Rauch J, von Kriegsheim A, Kolch W. Raf family kinases: old dogs have learned new tricks. Genes Cancer 2011; 2:232-60. [PMID: 21779496 PMCID: PMC3128629 DOI: 10.1177/1947601911407323] [Citation(s) in RCA: 272] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
First identified in the early 1980s as retroviral oncogenes, the Raf proteins have been the objects of intense research. The discoveries 10 years later that the Raf family members (Raf-1, B-Raf, and A-Raf) are bona fide Ras effectors and upstream activators of the ubiquitous ERK pathway increased the interest in these proteins primarily because of the central role that this cascade plays in cancer development. The important role of Raf in cancer was corroborated in 2002 with the discovery of B-Raf genetic mutations in a large number of tumors. This led to intensified drug development efforts to target Raf signaling in cancer. This work yielded not only recent clinical successes but also surprising insights into the regulation of Raf proteins by homodimerization and heterodimerization. Surprising insights also came from the hunt for new Raf targets. Although MEK remains the only widely accepted Raf substrate, new kinase-independent roles for Raf proteins have emerged. These include the regulation of apoptosis by suppressing the activity of the proapoptotic kinases, ASK1 and MST2, and the regulation of cell motility and differentiation by controlling the activity of Rok-α. In this review, we discuss the regulation of Raf proteins and their role in cancer, with special focus on the interacting proteins that modulate Raf signaling. We also describe the new pathways controlled by Raf proteins and summarize the successes and failures in the development of efficient anticancer therapies targeting Raf. Finally, we also argue for the necessity of more systemic approaches to obtain a better understanding of how the Ras-Raf signaling network generates biological specificity.
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Affiliation(s)
- David Matallanas
- Systems Biology Ireland, University College Dublin, Dublin, Ireland
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341
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Castoria G, D'Amato L, Ciociola A, Giovannelli P, Giraldi T, Sepe L, Paolella G, Barone MV, Migliaccio A, Auricchio F. Androgen-induced cell migration: role of androgen receptor/filamin A association. PLoS One 2011; 6:e17218. [PMID: 21359179 PMCID: PMC3040221 DOI: 10.1371/journal.pone.0017218] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Accepted: 01/25/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Androgen receptor (AR) controls male morphogenesis, gametogenesis and prostate growth as well as development of prostate cancer. These findings support a role for AR in cell migration and invasiveness. However, the molecular mechanism involved in AR-mediated cell migration still remains elusive. METHODOLOGY/PRINCIPAL FINDINGS Mouse embryo NIH3T3 fibroblasts and highly metastatic human fibrosarcoma HT1080 cells harbor low levels of transcriptionally incompetent AR. We now report that, through extra nuclear action, AR triggers migration of both cell types upon stimulation with physiological concentrations of the androgen R1881. We analyzed the initial events leading to androgen-induced cell migration and observed that challenging NIH3T3 cells with 10 nM R1881 rapidly induces interaction of AR with filamin A (FlnA) at cytoskeleton. AR/FlnA complex recruits integrin beta 1, thus activating its dependent cascade. Silencing of AR, FlnA and integrin beta 1 shows that this ternary complex controls focal adhesion kinase (FAK), paxillin and Rac, thereby driving cell migration. FAK-null fibroblasts migrate poorly and Rac inhibition by EHT impairs motility of androgen-treated NIH3T3 cells. Interestingly, FAK and Rac activation by androgens are independent of each other. Findings in human fibrosarcoma HT1080 cells strengthen the role of Rac in androgen signaling. The Rac inhibitor significantly impairs androgen-induced migration in these cells. A mutant AR, deleted of the sequence interacting with FlnA, fails to mediate FAK activation and paxillin tyrosine phosphorylation in androgen-stimulated cells, further reinforcing the role of AR/FlnA interaction in androgen-mediated motility. CONCLUSIONS/SIGNIFICANCE The present report, for the first time, indicates that the extra nuclear AR/FlnA/integrin beta 1 complex is the key by which androgen activates signaling leading to cell migration. Assembly of this ternary complex may control organ development and prostate cancer metastasis.
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Affiliation(s)
- Gabriella Castoria
- Dipartimento di Patologia Generale, II Università di Napoli, Napoli, Italy
| | - Loredana D'Amato
- Dipartimento di Patologia Generale, II Università di Napoli, Napoli, Italy
| | | | - Pia Giovannelli
- Dipartimento di Patologia Generale, II Università di Napoli, Napoli, Italy
| | - Tiziana Giraldi
- Dipartimento di Patologia Generale, II Università di Napoli, Napoli, Italy
| | - Leandra Sepe
- Dipartimento di Biochimica e Biotecnologie Mediche, Università ‘Federico II’, Napoli, Italy
| | - Giovanni Paolella
- Dipartimento di Biochimica e Biotecnologie Mediche, Università ‘Federico II’, Napoli, Italy
| | - Maria Vittoria Barone
- European Laboratory for the Investigation of Food Induced Disease, Dipartimento di Pediatria, Università ‘Federico II’, Napoli, Italy
| | - Antimo Migliaccio
- Dipartimento di Patologia Generale, II Università di Napoli, Napoli, Italy
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342
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Kamen LA, Schlessinger J, Lowell CA. Pyk2 is required for neutrophil degranulation and host defense responses to bacterial infection. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2011; 186:1656-65. [PMID: 21187437 PMCID: PMC3248398 DOI: 10.4049/jimmunol.1002093] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The appropriate regulation of neutrophil activation is critical for maintaining host defense and limiting inflammation. Polymorphonuclear neutrophils (PMNs) express a number of cytoplasmic tyrosine kinases that regulate signaling pathways leading to activation. One of the most highly expressed, but least studied, kinases in PMNs is proline rich kinase 2 (Pyk2). By analogy to the related focal adhesion kinase, Pyk2 has been implicated in regulating PMN adhesion and migration; however, its physiologic function has yet to be described. Using pyk2(-/-) mice, we found that this kinase was required for integrin-mediated degranulation responses, but was not involved in adhesion-induced cell spreading or activation of superoxide production. Pyk2-deficient PMNs also manifested reduced migration on fibrinogen-coated surfaces. The absence of Pyk2 resulted in a severe reduction in paxillin and Vav phosphorylation following integrin ligation, which likely accounts for the poor degranulation and cell migration. Pyk2(-/-) mice were unable to efficiently clear infection with Staphylococcus aureus in a skin abscess model, owing in part to the poor release of granule contents at the site of infection. However, Pyk2-deficient PMNs responded normally to soluble agonists, demonstrating that this kinase functions mainly in the integrin pathway. These data demonstrate the unrealized physiologic role of this kinase in regulating the adhesion-mediated release of PMN granule contents.
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Affiliation(s)
- Lynn A. Kamen
- Program in Immunology and the Department of Laboratory Medicine University of California, San Francisco, CA
| | - Joseph Schlessinger
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT
| | - Clifford A. Lowell
- Program in Immunology and the Department of Laboratory Medicine University of California, San Francisco, CA
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343
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Cortesio CL, Boateng LR, Piazza TM, Bennin DA, Huttenlocher A. Calpain-mediated proteolysis of paxillin negatively regulates focal adhesion dynamics and cell migration. J Biol Chem 2011; 286:9998-10006. [PMID: 21270128 DOI: 10.1074/jbc.m110.187294] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The dynamic turnover of integrin-mediated adhesions is important for cell migration. Paxillin is an adaptor protein that localizes to focal adhesions and has been implicated in cell motility. We previously reported that calpain-mediated proteolysis of talin1 and focal adhesion kinase mediates adhesion disassembly in motile cells. To determine whether calpain-mediated paxillin proteolysis regulates focal adhesion dynamics and cell motility, we mapped the preferred calpain proteolytic site in paxillin. The cleavage site is between the paxillin LD1 and LD2 motifs and generates a C-terminal fragment that is similar in size to the alternative product paxillin delta. The calpain-generated proteolytic fragment, like paxillin delta, functions as a paxillin antagonist and impairs focal adhesion disassembly and migration. We generated mutant paxillin with a point mutation (S95G) that renders it partially resistant to calpain proteolysis. Paxillin-deficient cells that express paxillin S95G display increased turnover of zyxin-containing adhesions using time-lapse microscopy and also show increased migration. Moreover, cancer-associated somatic mutations in paxillin are common in the N-terminal region between the LD1 and LD2 motifs and confer partial calpain resistance. Taken together, these findings suggest a novel role for calpain-mediated proteolysis of paxillin as a negative regulator of focal adhesion dynamics and migration that may function to limit cancer cell invasion.
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Affiliation(s)
- Christa L Cortesio
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, Wisconsin 53706, USA
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344
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Yu HG, Nam JO, Miller NLG, Tanjoni I, Walsh C, Shi L, Kim L, Chen XL, Tomar A, Lim ST, Schlaepfer DD. p190RhoGEF (Rgnef) promotes colon carcinoma tumor progression via interaction with focal adhesion kinase. Cancer Res 2011; 71:360-70. [PMID: 21224360 DOI: 10.1158/0008-5472.can-10-2894] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Focal adhesion kinase (FAK) functions downstream of integrins and growth factor receptors to promote tumor cell motility and invasion. In colorectal cancer, FAK is activated by amidated gastrin, a protumorigenic hormone. However, it is unclear how FAK receives signals from the gastrin receptor or other G-protein-coupled receptors that can promote cell motility and invasion. The Rho guanine-nucleotide exchange factor p190RhoGEF (Rgnef) binds FAK and facilitates fibroblast focal adhesion formation on fibronectin. Here we report that Rgnef mRNA and protein expression are significantly increased during colorectal tumor progression. In human colon carcinoma cells, Rgnef forms a complex with FAK and upon gastrin stimulation, FAK translocates to newly-forming focal adhesions where it facilitates tyrosine phosphorylation of paxillin. short hairpin (shRNA)-mediated knockdown of Rgnef or FAK, or pharmacological inhibition of FAK activity, is sufficient to block gastrin-stimulated paxillin phosphorylation, cell motility, and invadopodia formation in a manner dependent upon upstream cholecystokinin-2 receptor expression. Overexpression of the C-terminal region of Rgnef (Rgnef-C, amino acid 1,279-1,582) but not Rgnef-CΔFAK (amino acid 1,302-1,582 lacking the FAK binding site) disrupted endogenous Rgnef-FAK interaction and prevented paxillin phosphorylation and cell motility stimulated by gastrin. Rgnef-C-expressing cells formed smaller, less invasive tumors with reduced tyrosine phosphorylation of paxillin upon orthotopic implantation, compared with Rgnef-CΔFAK-expressing cells. Our studies identify Rgnef as a novel regulator of colon carcinoma motility and invasion, and they show that a Rgnef-FAK linkage promotes colon carcinoma progression in vivo.
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Affiliation(s)
- Hong-Gang Yu
- Department of Reproductive Medicine, Moores Cancer Center, UCSD, La Jolla, California 92093, USA
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Abstract
Cell migration is a fundamental process that controls morphogenesis and inflammation. Its deregulation causes or is part of many diseases, including autoimmune syndromes, chronic inflammation, mental retardation, and cancer. Cell migration is an integral part of the cell biology, embryology, immunology, and neuroscience fields; as such, it has benefited from quantum leaps in molecular biology, biochemistry, and imaging techniques, and the emergence of the genomic and proteomic era. Combinations of these techniques have revealed new and exciting insights that explain how cells adhere and move, how the migration of multiple cells are coordinated and regulated, and how the cells interact with neighboring cells and/or react to changes in their microenvironment. This introduction provides a primer of the molecular and cellular insights, particularly the signaling networks, which control the migration of individual cells as well as collective migrations. The rest of the chapters are devoted to describe in detail some of the most salient technical advances that have illuminated the field of cell migration in recent years.
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Watanabe-Nakayama T, Machida SI, Afrin R, Ikai A. Microscoop for manipulation of micro-objects: use of fabricated cantilever with atomic force microscope. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2010; 6:2853-2857. [PMID: 21104829 DOI: 10.1002/smll.201001632] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
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347
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Karginov AV, Zou Y, Shirvanyants D, Kota P, Dokholyan NV, Young DD, Hahn KM, Deiters A. Light regulation of protein dimerization and kinase activity in living cells using photocaged rapamycin and engineered FKBP. J Am Chem Soc 2010; 133:420-3. [PMID: 21162531 DOI: 10.1021/ja109630v] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
We developed a new system for light-induced protein dimerization in living cells using a photocaged analogue of rapamycin together with an engineered rapamycin binding domain. Using focal adhesion kinase as a target, we demonstrated successful light-mediated regulation of protein interaction and localization in living cells. Modification of this approach enabled light-triggered activation of a protein kinase and initiation of kinase-induced phenotypic changes in vivo.
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Affiliation(s)
- Andrei V Karginov
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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348
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Mackinnon AC, Tretiakova M, Henderson L, Mehta RG, Yan BC, Joseph L, Krausz T, Husain AN, Reid ME, Salgia R. Paxillin expression and amplification in early lung lesions of high-risk patients, lung adenocarcinoma and metastatic disease. J Clin Pathol 2010; 64:16-24. [PMID: 21045234 PMCID: PMC3002839 DOI: 10.1136/jcp.2010.075853] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Background Paxillin is a modular protein that localises to cell adhesion sites where it facilitates bidirectional communication between the intracellular actin cytoskeleton and the extracellular matrix. These complex and dynamic interactions are essential for cell adhesion, cell migration and cell survival. The authors have previously demonstrated that paxillin is overexpressed in lung cancer tissues and identified somatic paxillin mutations in 9% of lung cancers. A murine in vivo xenograft model of the most common paxillin mutation (A127T) showed increased cell proliferation and invasive tumour growth, establishing an important role for paxillin in the development of lung cancer. Methods The authors analysed 279 bronchoscopy-aided biopsy specimens from 92 high-risk patients. Adenocarcinoma with bronchioloalveolar features and pure bronchioloalveolar carcinoma (BAC) were analysed with fluorescence in situ hybridisation (FISH) and immunohistochemistry (IHC). Results Paxillin is overexpressed in premalignant areas of hyperplasia, squamous metaplasia and goblet cell metaplasia, as well as dysplastic lesions and carcinoma in high-risk patients. Concordance between increased paxillin gene copy number and paxillin overexpression was observed in cases of adenocarcinoma eusomic for chromosome 12. Conclusions Paxillin overexpression occurs during the earliest stages of lung cancer development. FISH and IHC analysis of lung adenocarcinoma suggests that relatively small-scale genomic rearrangements of chromosome 12 are associated with paxillin overexpression in lung adenocarcinoma.
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Affiliation(s)
- Alexander C Mackinnon
- Department of Pathology, University of Chicago Medical Center, Chicago, Illinois 60637, USA.
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349
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Li Y, Wang JP, Santen RJ, Kim TH, Park H, Fan P, Yue W. Estrogen stimulation of cell migration involves multiple signaling pathway interactions. Endocrinology 2010; 151:5146-56. [PMID: 20861240 PMCID: PMC2954727 DOI: 10.1210/en.2009-1506] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Hormone-dependent breast cancers respond to inhibitors of estrogen synthesis or action with tumor regression and with a reduction of new metastases. The mechanisms underlying the effects of estrogen on metastasis likely differ from those on tumor regression. Cell migration is a key first step in the metastatic process. Based on our prior work and other published data, we designed and tested a working model that suggested that estrogen receptor α, epidermal growth factor receptor, focal adhesion kinase (FAK), paxillin, phosphatidylinositol 3 kinase, p60 Src tyrosine kinase (c-Src), c-Jun N-terminal kinase, and MAPK interact to facilitate estradiol (E(2))-induced cell migration. Accordingly, we examined the effect of E(2) on activation of these pathways and demonstrated mechanistic effects by blocking each component and assessing cell migration as a biologic endpoint. Initial studies validated a robust cell migration assay characterized by highly reproducible, dose-dependent responses to E(2). Examining various mechanisms involved in migration, we showed that E(2) induced activation of c-Src, FAK, and paxillin with early peaks within 5-30 min and later peaks at 24 h. ERK and protein kinase B phosphorylation exhibited only early peaks. Blockade of various steps in these signaling pathways with use of small interfering RNA or specific inhibitors demonstrated mechanistic effects of these signaling molecules on cell migration. Our results suggest that the effects of E(2) on cell migration involve multiple, interacting signaling pathways. Important effects are mediated by the MAPK, phosphatidylinositol 3 kinase, and c-Jun N-terminal kinase pathways and use FAK, paxillin, and c-Src for activation. Each pathway represents a potential target for blocking cell migration and metastasis of breast cancer cells.
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Affiliation(s)
- Yan Li
- Division of Endocrinology, Department of Medicine, University of Virginia Health Sciences System, Virginia 22908, USA
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Downstream of identity genes: muscle-type-specific regulation of the fusion process. Dev Cell 2010; 19:317-28. [PMID: 20708593 DOI: 10.1016/j.devcel.2010.07.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2009] [Revised: 04/10/2010] [Accepted: 05/18/2010] [Indexed: 11/20/2022]
Abstract
In all metazoan organisms, the diversification of cell types involves determination of cell fates and subsequent execution of specific differentiation programs. During Drosophila myogenesis, identity genes specify the fates of founder myoblasts, from which derive all individual larval muscles. Here, to understand how cell fate information residing within founders is translated during differentiation, we focus on three identity genes, eve, lb, and slou, and how they control the size of individual muscles by regulating the number of fusion events. They achieve this by setting expression levels of Mp20, Pax, and mspo, three genes that regulate actin dynamics and cell adhesion and, as we show here, modulate the fusion process in a muscle-specific manner. Thus, these data show how the identity information implemented by transcription factors is translated via target genes into cell-type-specific programs of differentiation.
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