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Eshaq AM, Flanagan TW, Hassan SY, Al Asheikh SA, Al-Amoudi WA, Santourlidis S, Hassan SL, Alamodi MO, Bendhack ML, Alamodi MO, Haikel Y, Megahed M, Hassan M. Non-Receptor Tyrosine Kinases: Their Structure and Mechanistic Role in Tumor Progression and Resistance. Cancers (Basel) 2024; 16:2754. [PMID: 39123481 PMCID: PMC11311543 DOI: 10.3390/cancers16152754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Revised: 06/30/2024] [Accepted: 07/29/2024] [Indexed: 08/12/2024] Open
Abstract
Protein tyrosine kinases (PTKs) function as key molecules in the signaling pathways in addition to their impact as a therapeutic target for the treatment of many human diseases, including cancer. PTKs are characterized by their ability to phosphorylate serine, threonine, or tyrosine residues and can thereby rapidly and reversibly alter the function of their protein substrates in the form of significant changes in protein confirmation and affinity for their interaction with protein partners to drive cellular functions under normal and pathological conditions. PTKs are classified into two groups: one of which represents tyrosine kinases, while the other one includes the members of the serine/threonine kinases. The group of tyrosine kinases is subdivided into subgroups: one of them includes the member of receptor tyrosine kinases (RTKs), while the other subgroup includes the member of non-receptor tyrosine kinases (NRTKs). Both these kinase groups function as an "on" or "off" switch in many cellular functions. NRTKs are enzymes which are overexpressed and activated in many cancer types and regulate variable cellular functions in response to extracellular signaling-dependent mechanisms. NRTK-mediated different cellular functions are regulated by kinase-dependent and kinase-independent mechanisms either in the cytoplasm or in the nucleus. Thus, targeting NRTKs is of great interest to improve the treatment strategy of different tumor types. This review deals with the structure and mechanistic role of NRTKs in tumor progression and resistance and their importance as therapeutic targets in tumor therapy.
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Affiliation(s)
- Abdulaziz M. Eshaq
- Department of Epidemiology and Biostatistics, Milken Institute School of Public Health, George Washington University, Washington, DC 20052, USA;
- College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia; (S.A.A.A.); (W.A.A.-A.); (M.O.A.); (M.O.A.)
| | - Thomas W. Flanagan
- Department of Pharmacology and Experimental Therapeutics, LSU Health Sciences Center, New Orleans, LA 70112, USA;
| | - Sofie-Yasmin Hassan
- Department of Pharmacy, Faculty of Science, Heinrich-Heine University Duesseldorf, 40225 Duesseldorf, Germany;
| | - Sara A. Al Asheikh
- College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia; (S.A.A.A.); (W.A.A.-A.); (M.O.A.); (M.O.A.)
| | - Waleed A. Al-Amoudi
- College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia; (S.A.A.A.); (W.A.A.-A.); (M.O.A.); (M.O.A.)
| | - Simeon Santourlidis
- Institute of Cell Therapeutics and Diagnostics, University Medical Center of Duesseldorf, 40225 Duesseldorf, Germany;
| | - Sarah-Lilly Hassan
- Department of Chemistry, Faculty of Science, Heinrich-Heine University Duesseldorf, 40225 Duesseldorf, Germany;
| | - Maryam O. Alamodi
- College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia; (S.A.A.A.); (W.A.A.-A.); (M.O.A.); (M.O.A.)
| | - Marcelo L. Bendhack
- Department of Urology, Red Cross University Hospital, Positivo University, Rua Mauá 1111, Curitiba 80030-200, Brazil;
| | - Mohammed O. Alamodi
- College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia; (S.A.A.A.); (W.A.A.-A.); (M.O.A.); (M.O.A.)
| | - Youssef Haikel
- Institut National de la Santé et de la Recherche Médicale, University of Strasbourg, 67000 Strasbourg, France;
- Department of Operative Dentistry and Endodontics, Dental Faculty, 67000 Strasbourg, France
- Pôle de Médecine et Chirurgie Bucco-Dentaire, Hôpital Civil, Hôpitaux Universitaire de Strasbourg, 67000 Strasbourg, France
| | - Mossad Megahed
- Clinic of Dermatology, University Hospital of Aachen, 52074 Aachen, Germany;
| | - Mohamed Hassan
- Institut National de la Santé et de la Recherche Médicale, University of Strasbourg, 67000 Strasbourg, France;
- Department of Operative Dentistry and Endodontics, Dental Faculty, 67000 Strasbourg, France
- Research Laboratory of Surgery-Oncology, Department of Surgery, Tulane University School of Medicine, New Orleans, LA 70112, USA
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The explorations of dynamic interactions of paxillin at the focal adhesions. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2022; 1870:140825. [PMID: 35926716 DOI: 10.1016/j.bbapap.2022.140825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 07/16/2022] [Accepted: 07/27/2022] [Indexed: 11/20/2022]
Abstract
Paxillin is one of the most important adapters in integrin-mediated adhesions that performs numerous crucial functions relying on its dynamic interactions. Its structural behavior serves different purposes, providing a base for several activities. The various domains of paxillin display different functions in the whole process of cell movements and have a significant role in cell adhesion, migration, signal transmission, and protein-protein interactions. On the other hand, some paxillin-associated proteins provide a unique spatiotemporal mechanism for regulating its dynamic characteristics in the tissue homeostasis and make it a more complex and decisive protein at the focal adhesions. This review briefly describes the structural adaptations and molecular mechanisms of recruitment of paxillin into adhesions, explains paxillin's binding dynamics and impact on adhesion stability and turnover, and reveals a variety of paxillin-associated regulatory mechanisms and how paxillin is embedded into the signaling networks.
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Michael E, Polydorides S, Promponas VJ, Skourides P, Archontis G. Recognition of LD motifs by the focal adhesion targeting domains of focal adhesion kinase and proline-rich tyrosine kinase 2-beta: Insights from molecular dynamics simulations. Proteins 2020; 89:29-52. [PMID: 32776636 DOI: 10.1002/prot.25992] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 06/21/2020] [Accepted: 07/26/2020] [Indexed: 12/13/2022]
Abstract
The focal adhesion kinase (FAK) and the proline-rich tyrosine kinase 2-beta (PYK2) are implicated in cancer progression and metastasis and represent promising biomarkers and targets for cancer therapy. FAK and PYK2 are recruited to focal adhesions (FAs) via interactions between their FA targeting (FAT) domains and conserved segments (LD motifs) on the proteins Paxillin, Leupaxin, and Hic-5. A promising new approach for the inhibition of FAK and PYK2 targets interactions of the FAK domains with proteins that promote localization at FAs. Advances toward this goal include the development of surface plasmon resonance, heteronuclear single quantum coherence nuclear magnetic resonance (HSQC-NMR) and fluorescence polarization assays for the identification of fragments or compounds interfering with the FAK-Paxillin interaction. We have recently validated this strategy, showing that Paxillin mimicking polypeptides with 2 to 3 LD motifs displace FAK from FAs and block kinase-dependent and independent functions of FAK, including downstream integrin signaling and FA localization of the protein p130Cas. In the present work we study by all-atom molecular dynamics simulations the recognition of peptides with the Paxillin and Leupaxin LD motifs by the FAK-FAT and PYK2-FAT domains. Our simulations and free-energy analysis interpret experimental data on binding of Paxillin and Leupaxin LD motifs at FAK-FAT and PYK2-FAT binding sites, and assess the roles of consensus LD regions and flanking residues. Our results can assist in the design of effective inhibitory peptides of the FAK-FAT: Paxillin and PYK2-FAT:Leupaxin complexes and the construction of pharmacophore models for the discovery of potential small-molecule inhibitors of the FAK-FAT and PYK2-FAT focal adhesion based functions.
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Affiliation(s)
- Eleni Michael
- Department of Physics, University of Cyprus, Nicosia, Cyprus
| | | | - Vasilis J Promponas
- Bioinformatics Research Laboratory, Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus
| | - Paris Skourides
- Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus
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Li D, Ding J, Wang X, Wang C, Wu T. Fibronectin Promotes Tyrosine Phosphorylation of Paxillin and Cell Invasiveness in the Gastric Cancer Cell Line AGS. TUMORI JOURNAL 2018; 95:769-79. [DOI: 10.1177/030089160909500621] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Aims and Background Paxillin is a central protein within the focal adhesion and serves as a critical transducer of signals from fibronectin. Although abnormal expression of fibronectin and paxillin is often observed during the development of human malignancies, the relationship between paxillin and cell invasion in gastric cancer is still unclear. The current study was designed to investigate the potential role and mechanisms of fibronectin in tyrosine phosphorylation of paxillin and in the invasiveness of gastric cancer cells. Methods Expression of paxillin in human gastric cancer samples was examined by immunohistochemical staining. A gastric cancer cell line, AGS, was stimulated by fibronectin with gradient concentrations, and expression of paxillin and phosphorylation of paxillin tyrosine 118 (tyr118) was detected by immunoprecipitation and Western blotting. The invasiveness of AGS cells was measured by the modified Boyden chamber assay. Small interfering RNA (siRNA) targeting paxillin was used to establish the role of paxillin (tyr118) in the process of cell invasion enhanced by fibronectin. siRNA targeting focal adhesion kinase (FAK) was used to verify the effect of FAK tyrosine 397 (tyr397) on phosphorylation of paxillin(tyr118). Results Positivity for paxillin staining in human gastric cancer was associated with tumor stage. AGS cell showed dose dependence on fibronectin for invasiveness and phosphorylation of paxillin (tyr118). Invasiveness and phosphorylation of paxillin(tyr118) in AGS cells reached their peak when the concentration of fibronectin reached 100 nmol/L. siRNA targeting paxillin decreased the phosphorylation of paxillin(tyr118) and the invasiveness of AGS cells significantly as compared with controls. Blockage of FAK(tyr397) can inhibit phosphorylation of paxillin(tyr118) stimulated by fibronectin. Conclusions Fibronectin promotes paxillin(tyr118) phosphorylation and invasiveness of AGS cells. Paxillin silencing by RNA interference inhibits the cell invasiveness stimulated by fibronectin. Paxillin is a key factor in the fibronectin-stimulated invasiveness of AGS cells.
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Affiliation(s)
- Dan Li
- Digestive Department, the First Affiliated Hospital of Fujian Medical University
| | - Jian Ding
- Digestive Department, the Union Hospital of Fujian Medical University, Fuzhou, Fujian, China. Dan Li and Jian Ding contributed equally to this research
| | - Xiaozhong Wang
- Digestive Department, the First Affiliated Hospital of Fujian Medical University
| | - Chengdang Wang
- Digestive Department, the Union Hospital of Fujian Medical University, Fuzhou, Fujian, China. Dan Li and Jian Ding contributed equally to this research
| | - Ting Wu
- Digestive Department, the Union Hospital of Fujian Medical University, Fuzhou, Fujian, China. Dan Li and Jian Ding contributed equally to this research
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Antoniades I, Stylianou P, Christodoulou N, Skourides PA. Addressing the Functional Determinants of FAK during Ciliogenesis in Multiciliated Cells. J Biol Chem 2016; 292:488-504. [PMID: 27895123 DOI: 10.1074/jbc.m116.767111] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 11/24/2016] [Indexed: 11/06/2022] Open
Abstract
We previously identified focal adhesion kinase (FAK) as an important regulator of ciliogenesis in multiciliated cells. FAK and other focal adhesion (FA) proteins associate with the basal bodies and their striated rootlets and form complexes named ciliary adhesions (CAs). CAs display similarities with FAs but are established in an integrin independent fashion and are responsible for anchoring basal bodies to the actin cytoskeleton during ciliogenesis as well as in mature multiciliated cells. FAK down-regulation leads to aberrant ciliogenesis due to impaired association between the basal bodies and the actin cytoskeleton, suggesting that FAK is an important regulator of the CA complex. However, the mechanism through which FAK functions in the complex is not clear, and in this study we examined the role of this protein in both ciliogenesis and ciliary function. We show that localization of FAK at CAs depends on interactions taking place at the amino-terminal (FERM) and carboxyl-terminal (FAT) domains and that both domains are required for proper ciliogenesis and ciliary function. Furthermore, we show that an interaction with another CA protein, paxillin, is essential for correct localization of FAK in multiciliated cells. This interaction is indispensable for both ciliogenesis and ciliary function. Finally, we provide evidence that despite the fact that FAK is in the active, open conformation at CAs, its kinase activity is dispensable for ciliogenesis and ciliary function revealing that FAK plays a scaffolding role in multiciliated cells. Overall these data show that the role of FAK at CAs displays similarities but also important differences compared with its role at FAs.
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Affiliation(s)
- Ioanna Antoniades
- From the Laboratory of Cell Biology and Molecular Embryology, Department of Biological Sciences, University of Cyprus, 1 University Avenue, Nicosia 2109, Cyprus
| | - Panayiota Stylianou
- From the Laboratory of Cell Biology and Molecular Embryology, Department of Biological Sciences, University of Cyprus, 1 University Avenue, Nicosia 2109, Cyprus
| | - Neophytos Christodoulou
- From the Laboratory of Cell Biology and Molecular Embryology, Department of Biological Sciences, University of Cyprus, 1 University Avenue, Nicosia 2109, Cyprus
| | - Paris A Skourides
- From the Laboratory of Cell Biology and Molecular Embryology, Department of Biological Sciences, University of Cyprus, 1 University Avenue, Nicosia 2109, Cyprus
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Mohanty P, Bhatnagar S. Structural basis of focal adhesion targeting domain-mediated signaling in cardiac hypertrophy. J Recept Signal Transduct Res 2016; 37:38-50. [DOI: 10.3109/10799893.2016.1155067] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Pallavi Mohanty
- Computational and Structural Biology Laboratory, Division of Biotechnology, Netaji Subhas Institute of Technology, Dwarka, New Delhi, India
| | - Sonika Bhatnagar
- Computational and Structural Biology Laboratory, Division of Biotechnology, Netaji Subhas Institute of Technology, Dwarka, New Delhi, India
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7
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Walkiewicz KW, Girault JA, Arold ST. How to awaken your nanomachines: Site-specific activation of focal adhesion kinases through ligand interactions. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 119:60-71. [PMID: 26093249 DOI: 10.1016/j.pbiomolbio.2015.06.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Revised: 06/07/2015] [Accepted: 06/14/2015] [Indexed: 01/12/2023]
Abstract
The focal adhesion kinase (FAK) and the related protein-tyrosine kinase 2-beta (Pyk2) are highly versatile multidomain scaffolds central to cell adhesion, migration, and survival. Due to their key role in cancer metastasis, understanding and inhibiting their functions are important for the development of targeted therapy. Because FAK and Pyk2 are involved in many different cellular functions, designing drugs with partial and function-specific inhibitory effects would be desirable. Here, we summarise recent progress in understanding the structural mechanism of how the tug-of-war between intramolecular and intermolecular interactions allows these protein 'nanomachines' to become activated in a site-specific manner.
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Affiliation(s)
- Katarzyna W Walkiewicz
- King Abdullah University of Science and Technology (KAUST), Division of Biological and Environmental Sciences and Engineering, Computational Bioscience Research Center (CBRC), Thuwal, Saudi Arabia
| | - Jean-Antoine Girault
- Inserm, UMR-S 839, F-75005 Paris, France; Université Pierre & Marie Curie (UPMC), Sorbonne Universités, F-75005 Paris, France; Institut du Fer à Moulin, F-75005 Paris, France
| | - Stefan T Arold
- King Abdullah University of Science and Technology (KAUST), Division of Biological and Environmental Sciences and Engineering, Computational Bioscience Research Center (CBRC), Thuwal, Saudi Arabia.
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8
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Cooley MA, Harikrishnan K, Oppel JA, Miler SF, Barth JL, Haycraft CJ, Reddy SV, Scott Argraves W. Fibulin-1 is required for bone formation and Bmp-2-mediated induction of Osterix. Bone 2014; 69:30-8. [PMID: 25201465 PMCID: PMC4385289 DOI: 10.1016/j.bone.2014.07.038] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 07/22/2014] [Accepted: 07/27/2014] [Indexed: 01/16/2023]
Abstract
The extracellular matrix protein Fibulin-1 (Fbln1) has been shown to be involved in numerous processes including cardiovascular and lung development. Here we have examined the role of Fbln1 in bone formation. Alizarin red staining of skulls from Fbln1-deficient mice showed reduced mineralization of both membranous and endochondral bones. MicroCT (μCT) analysis of the calvarial bones (i.e., frontal, parietal and interparietal bones collectively) indicated that bone volume in Fbln1 nulls at neonatal stage P0 were reduced by 22% (p=0.015). Similarly, Fbln1 null frontal bones showed a 16% (p=0.035) decrease in bone volume, with a reduction in the interfrontal bone, and a discontinuity in the leading edge of the frontal bone. To determine whether Fbln1 played a role in osteoblast differentiation during bone formation, qPCR was used to measure the effects of Fbln1 deficiency on the expression of Osterix (Osx), a transcription factor essential for osteoblast differentiation. This analysis demonstrated that Osx mRNA was significantly reduced in Fbln1-deficient calvarial bones at developmental stages E16.5 (p=0.049) and E17.5 (p=0.022). Furthermore, the ability of Bmp-2 to induce Osx expression was significantly diminished in Fbln1-deficient mouse embryo fibroblasts. Together, these findings indicate that Fbln1 is a new positive modulator of the formation of membranous bone and endochondral bone in the skull, acting as a positive regulator of Bmp signaling.
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Affiliation(s)
- Marion A Cooley
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC 29425, USA; Department of Oral Health Sciences, Medical University of South Carolina, Charleston, SC 29425, USA.
| | - Keerthi Harikrishnan
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - James A Oppel
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Sloan F Miler
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Jeremy L Barth
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Courtney J Haycraft
- Department of Oral Health Sciences, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Sakamuri V Reddy
- Charles P. Darby Children's Research Institute, Medical University of South Carolina, Charleston, SC 29425, USA
| | - W Scott Argraves
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC 29425, USA
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Kadaré G, Gervasi N, Brami-Cherrier K, Blockus H, El Messari S, Arold ST, Girault JA. Conformational dynamics of the focal adhesion targeting domain control specific functions of focal adhesion kinase in cells. J Biol Chem 2014; 290:478-91. [PMID: 25391654 DOI: 10.1074/jbc.m114.593632] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Focal adhesion (FA) kinase (FAK) regulates cell survival and motility by transducing signals from membrane receptors. The C-terminal FA targeting (FAT) domain of FAK fulfils multiple functions, including recruitment to FAs through paxillin binding. Phosphorylation of FAT on Tyr(925) facilitates FA disassembly and connects to the MAPK pathway through Grb2 association, but requires dissociation of the first helix (H1) of the four-helix bundle of FAT. We investigated the importance of H1 opening in cells by comparing the properties of FAK molecules containing wild-type or mutated FAT with impaired or facilitated H1 openings. These mutations did not alter the activation of FAK, but selectively affected its cellular functions, including self-association, Tyr(925) phosphorylation, paxillin binding, and FA targeting and turnover. Phosphorylation of Tyr(861), located between the kinase and FAT domains, was also enhanced by the mutation that opened the FAT bundle. Similarly phosphorylation of Ser(910) by ERK in response to bombesin was increased by FAT opening. Although FAK molecules with the mutation favoring FAT opening were poorly recruited at FAs, they efficiently restored FA turnover and cell shape in FAK-deficient cells. In contrast, the mutation preventing H1 opening markedly impaired FAK function. Our data support the biological importance of conformational dynamics of the FAT domain and its functional interactions with other parts of the molecule.
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Affiliation(s)
- Gress Kadaré
- From the INSERM, UMR-S 839, F-75005 Paris, France, the Université Pierre & Marie Curie (UPMC), Sorbonne Universités, F-75005 Paris, France, the Institut du Fer à Moulin, F-75005 Paris, France
| | - Nicolas Gervasi
- From the INSERM, UMR-S 839, F-75005 Paris, France, the Université Pierre & Marie Curie (UPMC), Sorbonne Universités, F-75005 Paris, France, the Institut du Fer à Moulin, F-75005 Paris, France
| | - Karen Brami-Cherrier
- From the INSERM, UMR-S 839, F-75005 Paris, France, the Université Pierre & Marie Curie (UPMC), Sorbonne Universités, F-75005 Paris, France, the Institut du Fer à Moulin, F-75005 Paris, France
| | - Heike Blockus
- From the INSERM, UMR-S 839, F-75005 Paris, France, the Université Pierre & Marie Curie (UPMC), Sorbonne Universités, F-75005 Paris, France, the Institut du Fer à Moulin, F-75005 Paris, France
| | - Said El Messari
- From the INSERM, UMR-S 839, F-75005 Paris, France, the Université Pierre & Marie Curie (UPMC), Sorbonne Universités, F-75005 Paris, France, the Institut du Fer à Moulin, F-75005 Paris, France
| | - Stefan T Arold
- the King Abdullah University of Science and Technology (KAUST), Division of Biological and Environmental Sciences and Engineering, Computational Bioscience Research Center (CBRC), Thuwal, Saudi Arabia, and the Centre de Biochimie Structurale, CNRS UMR5048, INSERM U1054, Université de Montpellier I & II, Montpellier, France
| | - Jean-Antoine Girault
- From the INSERM, UMR-S 839, F-75005 Paris, France, the Université Pierre & Marie Curie (UPMC), Sorbonne Universités, F-75005 Paris, France, the Institut du Fer à Moulin, F-75005 Paris, France,
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10
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Fang X, Liu X, Yao L, Chen C, Lin J, Ni P, Zheng X, Fan Q. New insights into FAK phosphorylation based on a FAT domain-defective mutation. PLoS One 2014; 9:e107134. [PMID: 25226367 PMCID: PMC4166415 DOI: 10.1371/journal.pone.0107134] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Accepted: 08/11/2014] [Indexed: 01/27/2023] Open
Abstract
Mounting evidence suggests that the FAK N-terminal (FERM) domain controls FAK phosphorylation and function; however, little is known regarding the role of the C terminal (FAT) domain in FAK regulation. We identified a patient-derived FAK mutant, in which a 27-amino acid segment was deleted from the C-terminal FAT domain (named FAK-Del33). When FAK-Del33 was overexpressed in specific tumor cell lines, Y397 phosphorylation increased compared with that observed in cells expressing FAK-WT. Here, we attempt to unveil the mechanism of this increased phosphorylation. Using cell biology experiments, we show that FAK-Del33 is incapable of co-localizing with paxillin, and has constitutively high Y397 phosphorylation. With a kinase-dead mutation, it showed phosphorylation of FAK-Del33 has enhanced through auto-phosphorylation. It was also demonstrated that phosphorylation of FAK-Del33 is not Src dependent or enhanced intermolecular interactions, and that the hyperphosphorylation can be lowered using increasing amounts of transfected FERM domain. This result suggests that Del33 mutation disrupting of FAT's structural integrity and paxillin binding capacity leads to incapable of targeting Focal adhesions, but has gained the capacity for auto-phosphorylation in cis.
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Affiliation(s)
- Xuqian Fang
- Department of Clinical Laboratory, Ruijin North Hospital, Ruijin Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, P. R. China
| | - Xiangfan Liu
- Faculty of Medical Laboratory Science, Shanghai JiaoTong University School of Medicine, Shanghai, P. R. China
| | - Ling Yao
- Department of Biochemistry and Molecular Biology, Shanghai JiaoTong University School of Medicine, Shanghai, P. R. China
| | - Changqiang Chen
- Department of Clinical Laboratory, Ruijin North Hospital, Ruijin Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, P. R. China
| | - Jiafei Lin
- Department of Clinical Laboratory, Ruijin North Hospital, Ruijin Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, P. R. China
| | - Peihua Ni
- Faculty of Medical Laboratory Science, Shanghai JiaoTong University School of Medicine, Shanghai, P. R. China
| | - Xinmin Zheng
- Department of Biochemistry and Molecular Biology, Shanghai JiaoTong University School of Medicine, Shanghai, P. R. China
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Qishi Fan
- Department of Clinical Laboratory, Ruijin North Hospital, Ruijin Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, P. R. China
- * E-mail:
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11
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How to find a leucine in a haystack? Structure, ligand recognition and regulation of leucine-aspartic acid (LD) motifs. Biochem J 2014; 460:317-29. [PMID: 24870021 DOI: 10.1042/bj20140298] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
LD motifs (leucine-aspartic acid motifs) are short helical protein-protein interaction motifs that have emerged as key players in connecting cell adhesion with cell motility and survival. LD motifs are required for embryogenesis, wound healing and the evolution of multicellularity. LD motifs also play roles in disease, such as in cancer metastasis or viral infection. First described in the paxillin family of scaffolding proteins, LD motifs and similar acidic LXXLL interaction motifs have been discovered in several other proteins, whereas 16 proteins have been reported to contain LDBDs (LD motif-binding domains). Collectively, structural and functional analyses have revealed a surprising multivalency in LD motif interactions and a wide diversity in LDBD architectures. In the present review, we summarize the molecular basis for function, regulation and selectivity of LD motif interactions that has emerged from more than a decade of research. This overview highlights the intricate multi-level regulation and the inherently noisy and heterogeneous nature of signalling through short protein-protein interaction motifs.
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12
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Focal adhesion dynamics are altered in schizophrenia. Biol Psychiatry 2013; 74:418-26. [PMID: 23482246 DOI: 10.1016/j.biopsych.2013.01.020] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 01/15/2013] [Accepted: 01/15/2013] [Indexed: 12/16/2022]
Abstract
BACKGROUND Evidence from genetic association studies implicate genes involved in neural migration associated with schizophrenia risk. Neural stem/progenitor cell cultures (neurosphere-derived cells) from olfactory mucosa of schizophrenia patients have significantly dysregulated expression of genes in focal adhesion kinase (FAK) signaling, a key pathway regulating cell adhesion and migration. The aim of this study was to investigate whether olfactory neurosphere-derived cells from schizophrenia patients have altered cell adhesion, cell motility, and focal adhesion dynamics. METHODS Olfactory neurosphere-derived cells from nine male schizophrenia patients and nine male healthy control subjects were used. Cells were assayed for cell adhesion and cell motility and analyzed for integrins and FAK proteins. Focal adhesions were counted and measured in fixed cells, and time-lapse imaging was used to assess cell motility and focal adhesion dynamics. RESULTS Patient-derived cells were less adhesive and more motile than cells derived from healthy control subjects, and their motility was reduced to control cell levels by integrin-blocking antibodies and by inhibition of FAK. Vinculin-stained focal adhesion complexes were significantly smaller and fewer in patient cells. Time-lapse imaging of cells expressing FAK tagged with green fluorescent protein revealed that the disassembly of focal adhesions was significantly faster in patient cells. CONCLUSIONS The evidence for altered motility and focal adhesion dynamics in patient-derived cells is consistent with dysregulated gene expression in the FAK signaling pathway in these cells. Alterations in cell adhesion dynamics and cell motility could bias the trajectory of brain development in schizophrenia.
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Activation of endogenous FAK via expression of its amino terminal domain in Xenopus embryos. PLoS One 2012; 7:e42577. [PMID: 22880041 PMCID: PMC3412797 DOI: 10.1371/journal.pone.0042577] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Accepted: 07/09/2012] [Indexed: 11/20/2022] Open
Abstract
Background The Focal Adhesion Kinase is a well studied tyrosine kinase involved in a wide number of cellular processes including cell adhesion and migration. It has also been shown to play important roles during embryonic development and targeted disruption of the FAK gene in mice results in embryonic lethality by day 8.5. Principal Findings Here we examined the pattern of phosphorylation of FAK during Xenopus development and found that FAK is phosphorylated on all major tyrosine residues examined from early blastula stages well before any morphogenetic movements take place. We go on to show that FRNK fails to act as a dominant negative in the context of the early embryo and that the FERM domain has a major role in determining FAK’s localization at the plasma membrane. Finally, we show that autonomous expression of the FERM domain leads to the activation of endogenous FAK in a tyrosine 397 dependent fashion. Conclusions Overall, our data suggest an important role for the FERM domain in the activation of FAK and indicate that integrin signalling plays a limited role in the in vivo activation of FAK at least during the early stages of development.
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Deramaudt TB, Dujardin D, Hamadi A, Noulet F, Kolli K, De Mey J, Takeda K, Rondé P. FAK phosphorylation at Tyr-925 regulates cross-talk between focal adhesion turnover and cell protrusion. Mol Biol Cell 2011; 22:964-75. [PMID: 21289086 PMCID: PMC3069021 DOI: 10.1091/mbc.e10-08-0725] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
FAK plays a key role in the regulation of cell migration. The authors show that the phosphorylation status of FAK at Tyr-925 is involved in FA turnover, formation of FAs, and increase in cell edge protrusion, together with activation of the p130CAS/Rac1 signaling pathway. Cell migration is a highly complex process that requires the coordinated formation of membrane protrusion and focal adhesions (FAs). Focal adhesion kinase (FAK), a major signaling component of FAs, is involved in the disassembly process of FAs through phosphorylation and dephosphorylation of its tyrosine residues, but the role of such phosphorylations in nascent FA formation and turnover near the cell front and in cell protrusion is less well understood. In the present study, we demonstrate that, depending on the phosphorylation status of Tyr-925 residue, FAK modulates cell migration via two specific mechanisms. FAK−/− mouse embryonic fibroblasts (MEFs) expressing nonphosphorylatable Y925F-FAK show increased interactions between FAK and unphosphorylated paxillin, which lead to FA stabilization and thus decreased FA turnover and reduced cell migration. Conversely, MEFs expressing phosphomimetic Y925E-FAK display unchanged FA disassembly rates, show increase in phosphorylated paxillin in FAs, and exhibit increased formation of nascent FAs at the cell leading edges. Moreover, Y925E-FAK cells present enhanced cell protrusion together with activation of the p130CAS/Dock180/Rac1 signaling pathway. Together, our results demonstrate that phosphorylation of FAK at Tyr-925 is required for FAK-mediated cell migration and cell protrusion.
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Affiliation(s)
- Therese B Deramaudt
- Laboratoire de Biophotonique et Pharmacologie, Unité Mixte de Recherche 7213, Centre National de la Recherche Scientifique, and Faculté de Pharmacie, Université de Strasbourg, 67401 Illkirch, France
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15
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Riggs D, Yang Z, Kloss J, Loftus JC. The Pyk2 FERM regulates Pyk2 complex formation and phosphorylation. Cell Signal 2010; 23:288-96. [PMID: 20849950 DOI: 10.1016/j.cellsig.2010.09.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Accepted: 09/06/2010] [Indexed: 11/25/2022]
Abstract
The focal adhesion kinase Pyk2 integrates signals from cell adhesion receptors, growth factor receptors, and G-protein-coupled receptors leading to the activation of intracellular signaling pathways that regulate cellular phenotypes. The intrinsic mechanism for the activation of Pyk2 activity remains to be fully defined. Previously, we reported that mutations in the N-terminal FERM domain result in loss of Pyk2 activity and expression of the FERM domain as an autonomous fragment inhibits Pyk2 activity. In the present study, we sought to determine the mechanism that underlies these effects. Utilizing differentially epitope-tagged Pyk2 constructs, we observed that Pyk2 forms oligomeric complexes in cells and that complex formation correlates positively with tyrosine phosphorylation. Similarly, when expressed as an autonomous fragment, the Pyk2 FERM domain formed a complex with other Pyk2 FERM domains but not the FAK FERM domain. When co-expressed with full-length Pyk2, the autonomously expressed Pyk2 FERM domain formed a complex with full-length Pyk2 preventing the formation of Pyk2 oligomers and resulting in reduced Pyk2 phosphorylation. Deletion of the FERM domain from Pyk2 enhanced Pyk2 complex formation and phosphorylation. Together, these data indicate that the Pyk2 FERM domain is involved in the regulation of Pyk2 activity by acting to regulate the formation of Pyk2 oligomers that are critical for Pyk2 activity.
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Affiliation(s)
- Daniel Riggs
- Department of Biochemistry and Molecular Biology, Mayo Clinic Arizona, Scottsdale, AZ 85259, USA
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Chan KT, Bennin DA, Huttenlocher A. Regulation of adhesion dynamics by calpain-mediated proteolysis of focal adhesion kinase (FAK). J Biol Chem 2010; 285:11418-26. [PMID: 20150423 DOI: 10.1074/jbc.m109.090746] [Citation(s) in RCA: 159] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The coordinated and dynamic regulation of adhesions is required for cell migration. We demonstrated previously that limited proteolysis of talin1 by the calcium-dependent protease calpain 2 plays a critical role in adhesion disassembly in fibroblasts (Franco, S. J., Rodgers, M. A., Perrin, B. J., Han, J., Bennin, D. A., Critchley, D. R., and Huttenlocher, A. (2004) Nat. Cell Biol. 6, 977-983). However, little is known about the contribution of other calpain substrates to the regulation of adhesion dynamics. We now provide evidence that calpain 2-mediated proteolysis of focal adhesion kinase (FAK) regulates adhesion dynamics in motile cells. We mapped the preferred calpain cleavage site between the two C-terminal proline-rich regions after Ser-745, resulting in a C-terminal fragment similar in size to the FAK-related non-kinase (FRNK). We generated mutant FAK with a point mutation (V744G) that renders FAK resistant to calpain proteolysis but retains other biochemical properties of FAK. Using time-lapse microscopy, we show that the dynamics of green fluorescent protein-talin1 are impaired in FAK-deficient cells. Expression of wild-type but not calpain-resistant FAK rescues talin dynamics in FAK-deficient cells. Taken together, our findings suggest a novel role for calpain proteolysis of FAK in regulating adhesion dynamics in motile cells.
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Affiliation(s)
- Keefe T Chan
- Department of Molecular and Cellular Pharmacology, University of Wisconsin, Madison, Wisconsin 53706, USA
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Shan Y, Yu L, Li Y, Pan Y, Zhang Q, Wang F, Chen J, Zhu X. Nudel and FAK as antagonizing strength modulators of nascent adhesions through paxillin. PLoS Biol 2009; 7:e1000116. [PMID: 19492042 PMCID: PMC2684528 DOI: 10.1371/journal.pbio.1000116] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2008] [Accepted: 04/15/2009] [Indexed: 01/09/2023] Open
Abstract
Adhesion and detachment are coordinated critical steps during cell migration. Conceptually, efficient migration requires both effective stabilization of membrane protrusions at the leading edge via nascent adhesions and their successful persistence during retraction of the trailing side via disruption of focal adhesions. As nascent adhesions are much smaller in size than focal adhesions, they are expected to exhibit a stronger adhesivity in order to achieve the coordination between cell front and back. Here, we show that Nudel knockdown by interference RNA (RNAi) resulted in cell edge shrinkage due to poor adhesions of membrane protrusions. Nudel bound to paxillin, a scaffold protein of focal contacts, and colocalized with it in areas of active membrane protrusions, presumably at nascent adhesions. The Nudel-paxillin interaction was disrupted by focal adhesion kinase (FAK) in a paxillin-binding-dependent manner. Forced localization of Nudel in all focal contacts by fusing it to paxillin markedly strengthened their adhesivity, whereas overexpression of structurally activated FAK or any paxillin-binding FAK mutant lacking the N-terminal autoinhibitory domain caused cell edge shrinkage. These results suggest a novel mechanism for selective reinforcement of nascent adhesions via interplays of Nudel and FAK with paxillin to facilitate cell migration.
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Affiliation(s)
- Yongli Shan
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Lihou Yu
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Yan Li
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Youdong Pan
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Qiangge Zhang
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Fubin Wang
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Jianfeng Chen
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Xueliang Zhu
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- * E-mail:
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Focal adhesion kinase regulates cell-cell contact formation in epithelial cells via modulation of Rho. Exp Cell Res 2008; 314:3187-97. [PMID: 18773890 DOI: 10.1016/j.yexcr.2008.08.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2008] [Revised: 08/15/2008] [Accepted: 08/15/2008] [Indexed: 12/31/2022]
Abstract
Focal Adhesion Kinase (FAK) is a non-receptor tyrosine kinase that plays a key role in cellular processes such as cell adhesion, migration, proliferation and survival. Recent studies have also implicated FAK in the regulation of cell-cell adhesion. Here, evidence is presented showing that siRNA-mediated suppression of FAK levels in NBT-II cells and expression of dominant negative mutants of FAK caused loss of epithelial cell morphology and inhibited the formation of cell-cell adhesions. Rac and Rho have been implicated in the regulation of cell-cell adhesions and can be regulated by FAK signaling. Expression of active Rac or Rho in NBT-II cells disrupted formation of cell-cell contacts, thus promoting a phenotype similar to FAK-depleted cells. The loss of intercellular contacts in FAK-depleted cells is prevented upon expression of a dominant negative Rho mutant, but not a dominant negative Rac mutant. Inhibition of FAK decreased tyrosine phosphorylation of p190RhoGAP and elevated the level of GTP-bound Rho. This suggests that FAK regulates cell-cell contact formation by regulation of Rho.
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Velasco-Velázquez MA, Salinas-Jazmín N, Mendoza-Patiño N, Mandoki JJ. Reduced paxillin expression contributes to the antimetastatic effect of 4-hydroxycoumarin on B16-F10 melanoma cells. Cancer Cell Int 2008; 8:8. [PMID: 18492274 PMCID: PMC2429896 DOI: 10.1186/1475-2867-8-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Accepted: 05/20/2008] [Indexed: 11/10/2022] Open
Abstract
Background 4-Hydroxycoumarin (4-HC) is a coumarin that lacks anticoagulant activity. 4-HC affects the cytoskeletal stability and decreases cell adhesion and motility of the melanoma cell line B16-F10. Together with integrins and other cytoskeletal proteins, paxillin participates in the regulation of cell adhesion and motility, acting as an adapter protein at focal adhesions. The present study determined the participation of paxillin in the reported effects of 4-HC and analyzed the role of paxillin in the formation of melanoma metastases. Results 4-HC decreased protein and mRNA levels of α- and β-paxillin isoforms in B16-F10 cells. Paxillin downregulation correlated with an inadequate translocation of paxillin to focal adhesions and a reduced phosphotyr118-paxillin pool. Consequently, 4-HC altered paxillin-mediated signaling, decreasing the phosphorylation of FAK and the level of GTP-bound Rac-1. These results partially explain the mechanism of the previously reported effects of 4-HC. Additionally, we studied the effect of 4-HC on metastatic potential of B16-F10 cells through experimental metastasis assays. In vitro treatment of cells with 4-HC inhibited their capability to originate pulmonary metastases. 4-HC did not affect cell proliferation or survival, demonstrating that its antimetastatic effect is unrelated to changes on cell viability. We also studied the importance of paxillin in metastasis by transfecting melanoma cells with paxillin-siRNA. Transfection produced a modest reduction on metastatic potential, indicating that: i) paxillin plays a role as inducer of melanoma metastasis; and ii) paxillin downregulation is not sufficient to explain the antimetastatic effect of 4-HC. Therefore, we evaluated other changes in gene expression by differential display RT-PCR analysis. Treatment with 4-HC produced a downregulation of Adhesion Regulating Molecule-1 (ARM-1), which correlated with a decreased adhesion of melanoma cells to lung slides. Conclusion This study shows that reduced paxillin expression is associated with the impaired cell adhesion and motility seen in 4-HC-treated cells and partially contributes to the antimetastatic effect of 4-HC. In contrast, the role of ARM-1 reduced expression in the effects of 4-HC is still to be clarified. The antimetastatic effect of 4-HC suggests that this compound, or others with similar mode of action, might be useful for the development of adjuvant therapies for melanoma.
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Affiliation(s)
- Marco A Velasco-Velázquez
- Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, Apdo, Postal 70-297, Ciudad Universitaria, México D,F, 04510, México.
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20
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Structural Basis for the Interaction between Focal Adhesion Kinase and CD4. J Mol Biol 2008; 375:1320-8. [DOI: 10.1016/j.jmb.2007.11.040] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2007] [Revised: 11/09/2007] [Accepted: 11/13/2007] [Indexed: 12/16/2022]
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21
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Scheswohl DM, Harrell JR, Rajfur Z, Gao G, Campbell SL, Schaller MD. Multiple paxillin binding sites regulate FAK function. J Mol Signal 2008; 3:1. [PMID: 18171471 PMCID: PMC2246129 DOI: 10.1186/1750-2187-3-1] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2007] [Accepted: 01/02/2008] [Indexed: 11/17/2022] Open
Abstract
Background FAK localization to focal adhesions is essential for its activation and function. Localization of FAK is mediated through the C-terminal focal adhesion targeting (FAT) domain. Recent structural analyses have revealed two paxillin-binding sites in the FAT domain of FAK. To define the role of paxillin binding to each site on FAK, point mutations have been engineered to specifically disrupt paxillin binding to each docking site on the FAT domain of FAK individually or in combination. Results These mutants have been characterized and reveal an important role for paxillin binding in FAK subcellular localization and signaling. One paxillin-binding site (comprised of α-helices 1 and 4 of the FAT domain) plays a more prominent role in localization than the other. Mutation of either paxillin-binding site has similar effects on FAK activation and downstream signaling. However, the sites aren't strictly redundant as each mutant exhibits phosphorylation/signaling defects distinct from wild type FAK and a mutant completely defective for paxillin binding. Conclusion The studies demonstrate that the two paxillin-binding sites of FAK are not redundant and that both sites are required for FAK function.
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Affiliation(s)
- Danielle M Scheswohl
- Department of Cell and Developmental Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
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22
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Tilghman RW, Parsons JT. Focal adhesion kinase as a regulator of cell tension in the progression of cancer. Semin Cancer Biol 2007; 18:45-52. [PMID: 17928235 DOI: 10.1016/j.semcancer.2007.08.002] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2007] [Accepted: 08/28/2007] [Indexed: 01/13/2023]
Abstract
Growing evidence indicates that critical steps in cancer progression such as cell adhesion, migration, and cell cycle progression are regulated by the composition and organization of the microenvironment. The adhesion of cancer cells to components of the microenvironment and the forces transmitted to the cells via the actinomyosin network and the signaling complexes organized within focal adhesions allow cancer cells to sense the local topography of the extracellular matrix and respond efficiently to proximal growth and migration promoting cues. Focal adhesion kinase (FAK) is a nonreceptor tyrosine kinase that is over expressed in a variety of cancers and plays an important role in cell adhesion, migration, and anchorage-dependent growth. In this review, we summarize evidence which implicate FAK in the ability of cells to sense and respond to local forces from the microenvironment through the regulation of adhesion dynamics and actinomyosin contractility, and we discuss the potential roles of FAK as a mechanosensor in the progression of cancer.
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Affiliation(s)
- Robert W Tilghman
- Department of Microbiology, University of Virginia Health System, Charlottesville, VA 22908, USA
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Khare S, Holgren C, Samarel AM. Deoxycholic acid differentially regulates focal adhesion kinase phosphorylation: role of tyrosine phosphatase ShP2. Am J Physiol Gastrointest Liver Physiol 2006; 291:G1100-12. [PMID: 16920701 DOI: 10.1152/ajpgi.00008.2006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Environmental factors, including dietary fats, are implicated in colonic carcinogenesis. Dietary fats modulate secondary bile acids including deoxycholic acid (DCA) concentrations in the colon, which are thought to contribute to the nutritional-related component of colon cancer risk. Here we demonstrate, for the first time, that DCA differentially regulated the site-specific phosphorylation of focal adhesion kinase (FAK). DCA decreased adhesion of HCA-7 cells to the substratum and induced dephosphorylation of FAK at tyrosine-576/577 (Tyr-576/577) and Tyr-925. Tyrosine phosphorylation of FAK at Tyr-397 remained unaffected by DCA stimulation. Interestingly, we found that c-Src was constitutively associated with FAK and DCA actually activated Src, despite no change in FAK-397 and an inhibition of FAK-576 phosphorylation. DCA concomitantly and significantly increased association of tyrosine phosphatase ShP2 with FAK. Incubation of immunoprecipitated FAK, in vitro, with glutathione-S-transferase-ShP2 fusion protein resulted in tyrosine dephosphorylation of FAK in a concentration-dependent manner. Antisense oligodeoxynucleotides directed against ShP2 decreased ShP2 protein levels and attenuated DCA-induced FAK dephosphorylation. Inhibition of FAK by adenoviral-mediated overexpression of FAK-related nonkinase and gene silencing of Shp2 both abolished DCA's effect on cell adhesion, thus providing a possible mechanism for inside-out signaling by DCA in colon cancer cells. Our results suggest that DCA differentially regulates focal adhesion complexes and that tyrosine phosphatase ShP2 has a role in DCA signaling.
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Affiliation(s)
- Sharad Khare
- Department of Gastroenterology, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois, USA
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Chang F, Lemmon CA, Park D, Romer LH. FAK potentiates Rac1 activation and localization to matrix adhesion sites: a role for betaPIX. Mol Biol Cell 2006; 18:253-64. [PMID: 17093062 PMCID: PMC1751318 DOI: 10.1091/mbc.e06-03-0207] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
FAK, a cytoplasmic protein tyrosine kinase, is activated and localized to focal adhesions upon cell attachment to extracellular matrix. FAK null cells spread poorly and exhibit altered focal adhesion turnover. Rac1 is a member of the Rho-family GTPases that promotes membrane ruffling, leading edge extension, and cell spreading. We investigated the activation and subcellular location of Rac1 in FAK null and FAK reexpressing fibroblasts. FAK reexpressers had a more robust pattern of Rac1 activation after cell adhesion to fibronectin than the FAK null cells. Translocation of Rac1 to focal adhesions was observed in FAK reexpressers, but seldom in FAK null cells. Experiments with constitutively active L61Rac1 and dominant negative N17Rac1 indicated that the activation state of Rac1 regulated its localization to focal adhesions. We demonstrated that FAK tyrosine-phosphorylated betaPIX and thereby increased its binding to Rac1. In addition, betaPIX facilitated the targeting of activated Rac1 to focal adhesions and the efficiency of cell spreading. These data indicate that FAK has a role in the activation and focal adhesion translocation of Rac1 through the tyrosine phosphorylation of betaPIX.
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Affiliation(s)
- Fumin Chang
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
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Cai X, Li M, Vrana J, Schaller MD. Glycogen synthase kinase 3- and extracellular signal-regulated kinase-dependent phosphorylation of paxillin regulates cytoskeletal rearrangement. Mol Cell Biol 2006; 26:2857-68. [PMID: 16537926 PMCID: PMC1430314 DOI: 10.1128/mcb.26.7.2857-2868.2006] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Paxillin is a 68-kDa focal adhesion-associated protein that plays an important role in controlling cell spreading and migration. Phosphorylation of paxillin regulates its biological activity and thus has warranted investigation. Serine 126 and serine 130 were previously identified as two major extracellular signal-regulated kinase (ERK)-dependent phosphorylation sites in Raf-transformed fibroblasts. Here serine 126 is identified as a phosphorylation site induced by lipopolysaccharide (LPS) stimulation of RAW264.7 cells. A number of other stimuli, including adhesion and colony-stimulating factor, induce serine 126 phosphorylation in RAW264.7 cells, and nerve growth factor (NGF) treatment induces serine 126 phosphorylation in PC12 cells. The kinase responsible for phosphorylation of this site is identified as glycogen synthase kinase 3 (GSK-3). Interestingly, this GSK-3-dependent phosphorylation is regulated via an ERK-dependent priming mechanism, i.e., phosphorylation of serine 130. Phosphorylation of S126/S130 was required to promote spreading in paxillin null cells, and LPS-induced spreading of RAW264.7 cells was inhibited by expression of the paxillin S126A/S130A mutant. Furthermore, this mutant also retarded NGF-induced PC12 cell neurite outgrowth. Hence, phosphorylation of paxillin on serines 126 and 130, which is mediated by an ERK/GSK-3 dual-kinase mechanism, plays an important role in cytoskeletal rearrangement.
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Affiliation(s)
- Xinming Cai
- Department of Cell and Developmental Biology, 534 Taylor Hall, CB # 7090, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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Wade R, Vande Pol S. Minimal features of paxillin that are required for the tyrosine phosphorylation of focal adhesion kinase. Biochem J 2006; 393:565-73. [PMID: 16253116 PMCID: PMC1360707 DOI: 10.1042/bj20051241] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Tyrosine phosphorylation of FAK (focal adhesion kinase) regulates signalling that results from the interaction of integrins with extracellular matrix and growth factor receptors. A critical step in this process is the phosphorylation of Tyr397 of FAK, which creates a binding site for Src family kinases, PI3K (phosphoinositide 3-kinase) and Shc (Src homology and collagen homology). An intact Tyr397 site is required for FAK-mediated regulation of cell migration, survival signals and full responsiveness to soluble growth factors. We showed previously that the adaptor protein paxillin is required for the overall tyrosine phosphorylation of FAK in embryonic stem cells [Wade, Bohl and Vande Pol (2002) Oncogene 21, 96-107]. In the present paper, we identify the minimal structural features of paxillin that are required to support overall FAK tyrosine phosphorylation and Tyr397 phosphorylation. Paxillin contains N-terminal leucine-rich LD motifs that bind directly to FAK and four LIM (Lin-11, Isl-1 and Mec-3) domains in the C-terminus. We show that paxillin LIM domains 1, 2 and 3 are each required for FAK tyrosine phosphorylation, while LIM4 is dispensable. In addition to paxillin LIM domains 1, 2 and 3, a single LD motif on paxillin is required to support FAK tyrosine phosphorylation in embryonic stem cells. Both sequence and spatial requirements exist for LD motifs to support FAK tyrosine phosphorylation. Interestingly, synthetic LD motifs that fail to bind FAK in vitro are able to fully support FAK tyrosine phosphorylation, indicating that minimal interactions of LD motifs with FAK suffice. Our results demonstrate at least four distinct structural domains of paxillin support at least three distinct functions that are each required for FAK tyrosine phosphorylation.
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Affiliation(s)
- Ramon Wade
- Department of Pathology, University of Virginia, P.O. Box 800904, Charlottesville, VA 22908-0904, U.S.A
| | - Scott Vande Pol
- Department of Pathology, University of Virginia, P.O. Box 800904, Charlottesville, VA 22908-0904, U.S.A
- To whom correspondence should be addressed (email )
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Hanada M, Tanaka K, Matsumoto Y, Nakatani F, Sakimura R, Matsunobu T, Li X, Okada T, Nakamura T, Takasaki M, Iwamoto Y. Focal adhesion kinase is activated in invading fibrosarcoma cells and regulates metastasis. Clin Exp Metastasis 2006; 22:485-94. [PMID: 16320111 DOI: 10.1007/s10585-005-3733-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2005] [Accepted: 10/04/2005] [Indexed: 01/08/2023]
Abstract
Focal adhesion kinase (FAK) is a nonreceptor tyrosine kinase that is overexpressed in several human cancers, and induces survival, proliferation and motility of cells in culture. Phosphorylation of FAK has been studied extensively in vitro, but little is known about its regulation during tumor invasion in vivo. In the current study, green fluorescent protein (GFP) was expressed stably in an invasive murine fibrosarcoma cell line for the purpose of discrimination between tumor and normal cells. Under fluorescence microscopy, the tumor was highly fluorescent, and the margin between the tumor and normal tissue was clearly demarcated. Using this invasion model, we showed localization of pY397-FAK expression in the infiltrative edge of tumors. We reproduced local invasion in vivo using a tumor tissue culture method in a three dimensional collagen gel. Phosphorylation of FAK is also upregulated in invading fibrosarcoma cells under in vitro conditions. Expression of the FAK C-terminal domain termed FRNK (FAK-related non-kinase) in 2,472 cells decreased FAK phosphorylation without changing total FAK levels. FRNK inhibited the motility of 2,472 cells, and reduced invasion in vitro. Although FRNK did not affect cell growth, it inhibited experimental metastases in syngenic mice. These results demonstrate that the phosphorylation of FAK might be specifically upregulated in invading fibrosarcoma cells and regulate their invasion and metastasis.
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Affiliation(s)
- Masuo Hanada
- Department of Orthopedic Surgery, Graduate School of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka, Japan
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28
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Ding F, Prutzman KC, Campbell SL, Dokholyan NV. Topological Determinants of Protein Domain Swapping. Structure 2006; 14:5-14. [PMID: 16407060 DOI: 10.1016/j.str.2005.09.008] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2005] [Revised: 09/06/2005] [Accepted: 09/07/2005] [Indexed: 11/20/2022]
Abstract
Protein domain swapping has been repeatedly observed in a variety of proteins and is believed to result from destabilization due to mutations or changes in environment. Based on results from our studies and others, we propose that structures of the domain-swapped proteins are mainly determined by their native topologies. We performed molecular dynamics simulations of seven different proteins, known to undergo domain swapping experimentally, under mildly denaturing conditions and found in all cases that the domain-swapped structures can be recapitulated by using protein topology in a simple protein model. Our studies further indicated that, in many cases, domain swapping occurs at positions around which the protein tends to unfold prior to complete unfolding. This, in turn, enabled prediction of protein structural elements that are responsible for domain swapping. In particular, two distinct domain-swapped dimer conformations of the focal adhesion targeting domain of focal adhesion kinase were predicted computationally and were supported experimentally by data obtained from NMR analyses.
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Affiliation(s)
- Feng Ding
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, North Carolina 27599, USA
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29
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Cohen LA, Guan JL. Residues within the First Subdomain of the FERM-like Domain in Focal Adhesion Kinase Are Important in Its Regulation. J Biol Chem 2005; 280:8197-207. [PMID: 15611137 DOI: 10.1074/jbc.m412021200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have previously described regulation of focal adhesion kinase (FAK) by its amino-terminal FERM-like domain through an autoinhibitory interaction with its kinase domain (Cooper, L. A., Shen, T. L., and Guan, J. L. (2003) Mol. Cell. Biol. 23, 8030-8041). Here we show that the first two subdomains of the FERM-like domain are independently capable of inhibiting phosphorylation of FAK in trans. We characterized several point mutations within the first subdomain of the FERM-like domain and find that mutation of Lys-38 to alanine results in a FAK mutant that is strongly hyperphosphorylated when expressed in mammalian cells, and promotes increased phosphorylation of the FAK substrate paxillin. A second mutation of Lys-78 to alanine results in a FAK mutant that is underphosphorylated, but can be activated by extracellular matrix stimuli. Like deletion of the amino terminus itself the K38A mutation is phosphorylated in suspension. The Delta375 truncation mutant of FAK is strongly phosphorylated both when Tyr-397 is mutated to phenylalanine, and in the presence of the Src inhibitor, PP2, suggesting that removal of the amino terminus can render FAK Src independent. This is in contrast to the K38A mutant that is not phosphorylated in the Y397F background, and which shows decreased phosphorylation in the presence of the Src inhibitor PP2, suggesting that regulation of FAK by Src is a secondary step in its activation. The K38A mutation weakens the interaction between the amino terminus of FAK and its own kinase domain, and disrupts the ability of the amino terminus to inhibit the phosphorylation of FAK in trans. The K38A mutation of FAK also increases the ability of FAK to promote cell cycle progression and cell migration, suggesting that hyperphosphorylation of this mutant can positively affect FAK function in cells. Together, these data strongly suggest a role for the first FAK subdomain of the FERM domain in its normal regulation and function in the cell.
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Affiliation(s)
- Lee Ann Cohen
- Department of Molecular Medicine, Cornell University, Ithaca, New York 14853, USA
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30
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Dixon RDS, Chen Y, Ding F, Khare SD, Prutzman KC, Schaller MD, Campbell SL, Dokholyan NV. New Insights into FAK Signaling and Localization Based on Detection of a FAT Domain Folding Intermediate. Structure 2004; 12:2161-71. [PMID: 15576030 DOI: 10.1016/j.str.2004.09.011] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2004] [Revised: 09/17/2004] [Accepted: 09/24/2004] [Indexed: 11/24/2022]
Abstract
Mounting evidence suggests that the focal adhesion targeting (FAT) domain, an antiparallel four-helix bundle, exists in alternative conformations that may modulate phosphorylation, ligand binding, and the subcellular localization of focal adhesion kinase (FAK). In order to characterize the conformational dynamics of the FAT domain, we have developed a novel method for reconstructing the folding pathway of the FAT domain by using discrete molecular dynamics (DMD) simulations, with free energy constraints derived from NMR hydrogen exchange data. The DMD simulations detect a folding intermediate, in which a cooperative unfolding event causes helix 1 to lose helical character while separating from the helix bundle. The conformational dynamic features of helix 1 in the intermediate state of the FAT domain are likely to facilitate Y926 phosphorylation, yet interfere with paxillin binding. The presence of this intermediate state in vivo may promote FAK signaling via the ERK/MAPK pathway and by release of FAK from focal adhesions.
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Affiliation(s)
- Richard D S Dixon
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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31
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Abstract
Src family nonreceptor protein tyrosine kinases transduce signals that control normal cellular processes such as cell proliferation, adhesion and motility. Normally, cellular Src is held in an inactive state, but in several cancer types, abnormal events lead to elevated kinase activity of the protein and cause pleiotropic cellular responses inducing transformation and metastasis. A prerequisite of the ability of a cancer cell to undergo metastasis into distant tissues is to penetrate surrounding extracellular matrices. These processes are facilitated by the integrin family of cell adhesion molecules. As is the case with Src, altered integrin activity or substrate affinity can contribute to the neoplastic phenotype. Therefore, understanding the interplay between Src and integrin function has been of intense interest over the past few years. This review focuses on the role of Src and integrin signaling in normal cells and how this is deregulated in human cancer. We will identify the key players in the integrin-mediated signaling pathways involved in cell motility and apoptosis, such as FAK, paxillin and p130(CAS), and discuss how Src signaling affects the formation of focal adhesions and the extracellular matrix.
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Affiliation(s)
- Martin P Playford
- Department of Cell and Developmental Biology, University of North Carolina, Chapel Hill, NC 27599, USA
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32
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Khyrul WAKM, LaLonde DP, Brown MC, Levinson H, Turner CE. The integrin-linked kinase regulates cell morphology and motility in a rho-associated kinase-dependent manner. J Biol Chem 2004; 279:54131-9. [PMID: 15485819 DOI: 10.1074/jbc.m410051200] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The integrin-linked kinase (ILK) is a multidomain focal adhesion protein implicated in signal transmission from integrin and growth factor receptors. We have determined that ILK regulates U2OS osteosarcoma cell spreading and motility in a manner requiring both kinase activity and localization. Overexpression of wild-type (WT) ILK resulted in suppression of cell spreading, polarization, and motility to fibronectin. Cell lines overexpressing kinase-dead (S343A) or paxillin binding site mutant ILK proteins display inhibited haptotaxis to fibronectin. Conversely, spreading and motility was potentiated in cells expressing the "dominant negative," non-targeting, kinase-deficient E359K ILK protein. Suppression of cell spreading and motility of WT ILK U2OS cells could be rescued by treatment with the Rho-associated kinase (ROCK) inhibitor Y-27632 or introduction of dominant negative ROCK or RhoA, suggesting these cells have increased RhoA signaling. Activation of focal adhesion kinase (FAK), a negative regulator of RhoA, was reduced in WT ILK cells, whereas overexpression of FAK rescued the observed defects in spreading and cell polarity. Thus, ILK-dependent effects on ROCK and/or RhoA signaling may be mediated through FAK.
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Affiliation(s)
- Wara A K M Khyrul
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York 13210, USA
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33
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García MG, Toney SJ, Hille MB. Focal adhesion kinase (FAK) expression and phosphorylation in sea urchin embryos. Gene Expr Patterns 2004; 4:223-34. [PMID: 15161103 DOI: 10.1016/j.modgep.2003.08.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2003] [Revised: 08/13/2003] [Accepted: 08/19/2003] [Indexed: 11/20/2022]
Abstract
We have cloned three cDNA isoforms of focal adhesion kinase (FAK) from the sea urchin, Lytechinus variegatus. The sea urchin FAK is more closely related to FAK from other deuterostomes than from invertebrate protostomes or to cell adhesion kinase beta (CAKbeta/Pyk2/FAK2). FAK is expressed in all cells of sea urchin embryos by the 120-cell stage and strongly in blastulae. Phospho-FAK concentrates on basal surfaces of epithelial cells in early blastulae and occurs in syncytial cables of primary mesenchyme cells (PMC). Inhibition of FAK by constructs of FAK-related non-kinase delays blastocoel expansion and early PMC ingression. These results suggest that FAK has roles in cell adhesion and in the shape and integrity of the epithelial cells in sea urchin embryos.
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Affiliation(s)
- María Guadalupe García
- Department of Biology, University of Washington, Box 351800, Seattle, WA 98195-1800, USA
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34
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Hoellerer MK, Noble MEM, Labesse G, Campbell ID, Werner JM, Arold ST. Molecular recognition of paxillin LD motifs by the focal adhesion targeting domain. Structure 2004; 11:1207-17. [PMID: 14527389 DOI: 10.1016/j.str.2003.08.010] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Focal adhesions (FAs) are large submembrane signaling complexes formed at sites of cellular attachment to the extracellular matrix. The interaction of LD motifs with their targets plays an important role in the assembly of FAs. We have determined the molecular basis for the recognition of two paxillin LD motifs by the FA targeting (FAT) domain of FA kinase using a combination of X-ray crystallography, solution NMR, and homology modeling. The four-helix FAT domain displays two LD binding sites on opposite sites of the molecule that bind LD peptides in a helical conformation. Threading studies suggest that the LD-interacting domain of p95PKL shares a common four-helical core with the FAT domain and the tail of vinculin, defining a structural family of LD motif binding modules.
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Affiliation(s)
- Maria K Hoellerer
- Biochemistry Department, South Parks Road, Oxford, OX1 3QU, United Kingdom
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35
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Dunty JM, Gabarra-Niecko V, King ML, Ceccarelli DFJ, Eck MJ, Schaller MD. FERM domain interaction promotes FAK signaling. Mol Cell Biol 2004; 24:5353-68. [PMID: 15169899 PMCID: PMC419890 DOI: 10.1128/mcb.24.12.5353-5368.2004] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2003] [Revised: 01/05/2004] [Accepted: 03/15/2004] [Indexed: 12/29/2022] Open
Abstract
From the results of deletion analyses, the FERM domain of FAK has been proposed to inhibit enzymatic activity and repress FAK signaling. We have identified a sequence in the FERM domain that is important for FAK signaling in vivo. Point mutations in this sequence had little effect upon catalytic activity in vitro. However, the mutant exhibits reduced tyrosine phosphorylation and dramatically reduced Src family kinase binding. Further, the abilities of the mutant to transduce biochemical signals and to promote cell migration were severely impaired. The results implicate a FERM domain interaction in cell adhesion-dependent activation of FAK and downstream signaling. We also show that the purified FERM domain of FAK interacts with full-length FAK in vitro, and mutation of this sequence disrupts the interaction. These findings are discussed in the context of models of FAK regulation by its FERM domain.
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Affiliation(s)
- Jill M Dunty
- Department of Cell and Developmental Biology, University of North Carolina at Chapel Hill, 27599, USA
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36
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Prutzman KC, Gao G, King ML, Iyer VV, Mueller GA, Schaller MD, Campbell SL. The Focal Adhesion Targeting Domain of Focal Adhesion Kinase Contains a Hinge Region that Modulates Tyrosine 926 Phosphorylation. Structure 2004; 12:881-91. [PMID: 15130480 DOI: 10.1016/j.str.2004.02.028] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2003] [Revised: 02/03/2004] [Accepted: 02/16/2004] [Indexed: 11/26/2022]
Abstract
The focal adhesion targeting (FAT) domain of focal adhesion kinase (FAK) is critical for recruitment of FAK to focal adhesions and contains tyrosine 926, which, when phosphorylated, binds the SH2 domain of Grb2. Structural studies have shown that the FAT domain is a four-helix bundle that exists as a monomer and a dimer due to domain swapping of helix 1. Here, we report the NMR solution structure of the avian FAT domain, which is similar in overall structure to the X-ray crystal structures of monomeric forms of the FAT domain, except that loop 1 is longer and less structured in solution. Residues in this region undergo temperature-dependent exchange broadening and sample aberrant phi and psi angles, which suggests that this region samples multiple conformations. We have also identified a mutant that dimerizes approximately 8 fold more than WT FAT domain and exhibits increased phosphorylation of tyrosine 926 both in vitro and in vivo.
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Affiliation(s)
- Kirk C Prutzman
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
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37
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Giannone G, Rondé P, Gaire M, Beaudouin J, Haiech J, Ellenberg J, Takeda K. Calcium rises locally trigger focal adhesion disassembly and enhance residency of focal adhesion kinase at focal adhesions. J Biol Chem 2004; 279:28715-23. [PMID: 15102844 DOI: 10.1074/jbc.m404054200] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Focal adhesion kinase (FAK) activity and Ca(2+) signaling led to a turnover of focal adhesions (FAs) required for cell spreading and migration. We used yellow Cameleon-2 (Ycam), a fluorescent protein-based Ca(2+) sensor fused to FAK or to a FAK-related non-kinase domain, to measure simultaneously local Ca(2+) variations at FA sites and FA dynamics. Discrete subcellular Ca(2+) oscillators initiate both propagating and abortive Ca(2+) waves in migrating U87 astrocytoma cells. Ca(2+)-dependent FA disassembly occurs when the Ca(2+) wave reaches individual FAs, indicating that local but not global Ca(2+) increases trigger FA disassembly. An unexpectedly rapid flux of FAK between cytosolic and FA compartments was revealed by fluorescence recovery after photobleaching studies. The FAK-Ycam recovery half-time (17 s) at FAs was slowed (to 29 s) by Ca(2+) elevation. FAK-related non-kinase domain-Ycam had a faster, Ca(2+)-insensitive recovery half-time (11 s), which is consistent with the effect of Ca(2+) on FAK-Ycam dynamics not being due to a general modification of the dynamics of FA components. Because FAK association at FAs was prolonged by Ca(2+) and FAK autophosphorylation was correlated to intracellular Ca(2+) levels, we propose that local Ca(2+) elevations increase the residency of FAK at FAs, possibly by means of tyrosine phosphorylation of FAK, thereby leading to increased activation of its effectors involved in FA disassembly.
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Affiliation(s)
- Grégory Giannone
- Laboratoire de Pharmacologie et Physicochimie des Interactions Cellulaires et Moléculaires, Unité Mixte de Recherche CNRS 7034, Université Louis Pasteur de Strasbourg, 67401 Illkirch, France
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38
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Gao G, Prutzman KC, King ML, Scheswohl DM, DeRose EF, London RE, Schaller MD, Campbell SL. NMR Solution Structure of the Focal Adhesion Targeting Domain of Focal Adhesion Kinase in Complex with a Paxillin LD Peptide. J Biol Chem 2004; 279:8441-51. [PMID: 14662767 DOI: 10.1074/jbc.m309808200] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Focal adhesion kinase (FAK) is a non-receptor tyrosine kinase that is regulated by integrins. Upon activation, FAK generates signals that modulate crucial cell functions, including cell proliferation, migration, and survival. The C-terminal focal adhesion targeting (FAT) sequence mediates localization of FAK to discrete regions in the cell called focal adhesions. Several binding partners for the FAT domain of FAK have been identified, including paxillin. We have determined the solution structure of the avian FAT domain in complex with a peptide mimicking the LD2 motif of paxillin by NMR spectroscopy. The FAT domain retains a similar fold to that found in the unliganded form when complexed to the paxillin-derived LD2 peptide, an antiparallel four-helix bundle. However, noticeable conformational changes were observed upon the LD2 peptide binding, especially the position of helix 4. Multiple lines of evidence, including the results obtained from isothermal titration calorimetry, intermolecular nuclear Overhauser effects, mutagenesis, and protection from paramagnetic line broadening, support the existence of two distinct paxillin-binding sites on the opposite faces of the FAT domain. The structure of the FAT domain-LD2 complex was modeled using the program HADDOCK based on our solution structure of the LD2-bound FAT domain and mutagenesis data. Our model of the FAT domain-LD2 complex provides insight into the molecular basis of FAK-paxillin binding interactions, which will aid in understanding the role of paxillin in FAK targeting and signaling.
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Affiliation(s)
- Guanghua Gao
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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39
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Cooper LA, Shen TL, Guan JL. Regulation of focal adhesion kinase by its amino-terminal domain through an autoinhibitory interaction. Mol Cell Biol 2003; 23:8030-41. [PMID: 14585964 PMCID: PMC262338 DOI: 10.1128/mcb.23.22.8030-8041.2003] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
We have investigated a role for the amino-terminal FERM-like domain of the focal adhesion kinase (FAK) as a negative regulator of its own activity and phosphorylation state. Deletion of the first 375 amino acids from the amino terminus of FAK increases its catalytic activity in vitro, its phosphorylation when expressed in mammalian cells, and the phosphorylation of a FAK substrate, paxillin. Deletion mutants are phosphorylated in suspension, suggesting that they are no longer regulated by adhesion. The amino terminus of FAK can interact with the kinase domain of FAK in vitro and in vivo, suggesting that it might act as an autoinhibitor of FAK activity. The amino terminus of FAK can act in trans to inhibit FAK phosphorylation when expressed in mammalian cells or to directly inhibit FAK activity in vitro. Expression of the amino terminus of FAK inhibits cell cycle progression in CHO cells, consistent with its inhibition of FAK phosphorylation and function in trans. A glutathione S-transferase fusion protein containing the cytoplasmic tail of the beta1 integrin stimulates FAK activity in vitro, suggesting that FAK could be regulated by molecular interactions with the amino terminus. Based on these and previous data, we propose a working model for activation of FAK in cell adhesion.
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Affiliation(s)
- Lee Ann Cooper
- Department of Molecular Medicine, Cornell University, Ithaca, NY 14853, USA
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40
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Miyamoto YJ, Andruss BF, Mitchell JS, Billard MJ, McIntyre BW. Diverse roles of integrins in human T lymphocyte biology. Immunol Res 2003; 27:71-84. [PMID: 12637769 DOI: 10.1385/ir:27:1:71] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
T lymphocytes are the primary cells responsible for maintaining the immune system. There are many intricate mechanisms involved in the regulation of T cells and the integrin family of adhesive surface proteins plays a pivotal role in the control of T lymphocyte activation and functions. Integrins are heterodimeric transmembrane proteins that are not merely adhesion molecules but also function in T cell coactivation by providing a scaffold for signaling and cytoskeletal proteins that are adept at transmitting signals from the inside of the cell to the outside ("inside-out signaling") or from the outside of the cell to the inside ("outside-in signaling"). The signaling property of integrins allows for rapid responses to changes in the microenviroment of the lymphocyte. Therefore, whether the T cell needs to adhere or detach, integrins can quickly accommodate either state of the cell. Once cells are guided to sites of infection, inflammation, or antigen presentation, integrins can also participate in the initiation, maintenance, or termination of the response. This review will focus on the aspects of integrin-mediated T cell coactivation, affinity and avidity control of integrins, signaling molecules involved with integrins, association of integrins in lipid microdomains, and negative regulation of integrins.
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Affiliation(s)
- Yuko J Miyamoto
- Department of Immunology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA
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41
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Kwong L, Wozniak MA, Collins AS, Wilson SD, Keely PJ. R-Ras promotes focal adhesion formation through focal adhesion kinase and p130(Cas) by a novel mechanism that differs from integrins. Mol Cell Biol 2003; 23:933-49. [PMID: 12529399 PMCID: PMC140691 DOI: 10.1128/mcb.23.3.933-949.2003] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
R-Ras regulates integrin function, but its effects on integrin signaling pathways have not been well described. We demonstrate that activation of R-Ras promoted focal adhesion formation and altered localization of the alpha2beta1 integrin from cell-cell to cell-matrix adhesions in breast epithelial cells. Constitutively activated R-Ras(38V) dramatically enhanced focal adhesion kinase (FAK) and p130(Cas) phosphorylation upon collagen stimulation or clustering of the alpha2beta1 integrin, even in the absence of increased ligand binding. Signaling events downstream of R-Ras differed from integrins and K-Ras, since pharmacological inhibition of Src or disruption of actin inhibited integrin-mediated FAK and p130(Cas) phosphorylation, focal adhesion formation, and migration in control and K-Ras(12V)-expressing cells but had minimal effect in cells expressing R-Ras(38V). Therefore, signaling from R-Ras to FAK and p130(Cas) has a component that is Src independent and not through classic integrin signaling pathways and a component that is Src dependent. R-Ras effector domain mutants and pharmacological inhibition suggest a partial role for phosphatidylinositol 3-kinase (PI3K), but not Raf, in R-Ras signaling to FAK and p130(Cas). However, PI3K cannot account for the Src-independent pathway, since simultaneous inhibition of both PI3K and Src did not completely block effects of R-Ras on FAK phosphorylation. Our results suggest that R-Ras promotes focal adhesion formation by signaling to FAK and p130(Cas) through a novel mechanism that differs from but synergizes with the alpha2beta1 integrin.
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Affiliation(s)
- Lina Kwong
- Department of Pharmacology, University of Wisconsin Medical School, Madison, Wisconsin 53706, USA
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42
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Dunty JM, Schaller MD. The N termini of focal adhesion kinase family members regulate substrate phosphorylation, localization, and cell morphology. J Biol Chem 2002; 277:45644-54. [PMID: 12223467 DOI: 10.1074/jbc.m201779200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The focal adhesion kinase (FAK) and cell adhesion kinase beta (CAKbeta, PYK2, CADTK, RAFTK) are highly homologous FAK family members, yet clearly have unique roles in the cell. Comparative analyses of FAK and CAKbeta have revealed intriguing differences in their activities. These differences were investigated further through the characterization of a set of FAK/CAKbeta chimeric kinases. CAKbeta exhibited greater catalytic activity than FAK in vitro, providing a molecular basis for differential substrate phosphorylation by FAK and CAKbeta in vivo. Furthermore, the N terminus may regulate catalytic activity since chimeras containing the FAK N terminus and CAKbeta catalytic domain exhibited a striking high level of catalytic activity and substrate phosphorylation. Unexpectedly, a modulatory role for the N termini in subcellular localization was also revealed. Chimeras containing the FAK N terminus and CAKbeta C terminus localized to focal adhesions, whereas chimeras containing the N and C termini of CAKbeta did not. Finally, prominent changes in cell morphology were induced upon expression of chimeras containing the CAKbeta N terminus, which were not associated with apoptotic cell death, cell cycle progression delay, or changes in Rho activity. These results demonstrate novel regulatory roles for the N terminus of FAK family kinases.
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Affiliation(s)
- Jill M Dunty
- Department of Cell and Developmental Biology, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina 27599, USA
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43
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Toutant M, Costa A, Studler JM, Kadaré G, Carnaud M, Girault JA. Alternative splicing controls the mechanisms of FAK autophosphorylation. Mol Cell Biol 2002; 22:7731-43. [PMID: 12391143 PMCID: PMC134714 DOI: 10.1128/mcb.22.22.7731-7743.2002] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Focal adhesion kinase (FAK) is activated following integrin engagement or stimulation of transmembrane receptors. Autophosphorylation of FAK on Tyr-397 is a critical event, allowing binding of Src family kinases and activation of signal transduction pathways. Tissue-specific alternative splicing generates several isoforms of FAK with different autophosphorylation rates. Despite its importance, the mechanisms of FAK autophosphorylation and the basis for differences between isoforms are not known. We addressed these questions using isoforms of FAK expressed in brain. Autophosphorylation of FAK(+), which is identical to that of "standard" FAK, was intermolecular in transfected cells, although it did not involve the formation of stable multimeric complexes. Coumermycin-induced dimerization of gyrase B-FAK(+) chimeras triggered autophosphorylation of Tyr-397. This was independent of cell adhesion but required the C terminus of the protein. In contrast, the elevated autophosphorylation of FAK(+6,7), the major neuronal splice isoform, was not accounted for by transphosphorylation. Specifically designed immune precipitate kinase assays confirmed that autophosphorylation of FAK(+) was intermolecular, whereas autophosphorylation of FAK(+6,7) or FAK(+7) was predominantly intramolecular and insensitive to the inhibitory effects of the N-terminal domain. Our results clarify the mechanisms of FAK activation and show how alternative splicing can dramatically alter the mechanism of autophosphorylation of a protein kinase.
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Aguirre Ghiso JA. Inhibition of FAK signaling activated by urokinase receptor induces dormancy in human carcinoma cells in vivo. Oncogene 2002; 21:2513-24. [PMID: 11971186 DOI: 10.1038/sj.onc.1205342] [Citation(s) in RCA: 167] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2002] [Revised: 01/17/2002] [Accepted: 01/18/2002] [Indexed: 11/09/2022]
Abstract
Activation of focal adhesion kinase (FAK), overexpressed in several human cancers, induces survival, proliferation and motility of cells in culture, but its functional importance in human tumor growth in vivo has not been elucidated. I explored the role of FAK in regulating tumorigenicity of human carcinoma cells, HEp3. These cells overexpress urokinase receptor (uPAR) which, by activating alpha5beta1 integrin, initiates an intracellular signal through FAK and Src leading to ERK activation and tumorigenicity in vivo. Down regulation of uPAR in these cells led to an approximately 3-5-fold reduction in FAK phosphorylation and association with Src and dormancy in vivo. Both FAK phosphorylation and ability to grow in vivo were restored by re-expression of uPAR. The FAK signaling pathway in T-HEp3 cells, measured by FAK phosphorylation, GTP-loaded Ras and ERK activation, was inhibited by transient or stable transfection of FAK related non-kinase (FRNK), known to have a dominant negative function, but not by a FRNK mutant version (S1034-FRNK). Most importantly, while vector- and mutant-S1034-FRNK transfected cells inoculated onto chicken embryo CAMs formed progressively growing tumors, the HA-FRNK-expressing T-HEp3 cells did not proliferate in vivo and remained dormant for at least 6 weeks. Both cell types had similar rate of apoptosis in vivo and the p38(SAPK) or PI3K-Akt signaling pathways were unaffected by FRNK. FRNK induced dormancy could be reverted by expression of an active-R4F-Mek1 mutant. These results show that active FAK is an important mediator of uPAR-regulated tumorigenicity of HEp3 cells and that interruption of FAK mitogenic signaling either through down-regulation of uPAR or by expression of FRNK can force human carcinoma cells into dormancy.
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Affiliation(s)
- Julio A Aguirre Ghiso
- Division of Medical Oncology, Department of Medicine, Rochelle Belfer Chemotherapy Foundation Laboratory, Mount Sinai School of Medicine, New York, NY 10029, USA.
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Rajfur Z, Roy P, Otey C, Romer L, Jacobson K. Dissecting the link between stress fibres and focal adhesions by CALI with EGFP fusion proteins. Nat Cell Biol 2002; 4:286-93. [PMID: 11912490 DOI: 10.1038/ncb772] [Citation(s) in RCA: 156] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Chromophore-assisted laser inactivation (CALI) is a light-mediated technique used to selectively inactivate proteins within cells. Here, we demonstrate that GFP can be used as a CALI reagent to locally inactivate proteins in living cells. We show that focused laser irradiation of EGFP-alpha-actinin expressed in Swiss 3T3 fibroblasts results in the detachment of stress fibres from focal adhesions (FAs), whereas the integrity of FAs, as determined by interference reflection microscopy (IRM), is preserved. Moreover, consistent with a function for focal adhesion kinase (FAK) in FA signalling and not FA structure, laser irradiation of EGFP-FAK did not cause either visible FA damage or stress fibre detachment, although in vitro CALI of isolated EGFP-FAK decreased its kinase activity, but not its binding to paxillin. These data indicate that CALI of specific FA components may be used to precisely dissect the functional significance of individual proteins required for the maintenance of this cytoskeletal structure. In vitro CALI experiments also demonstrated a reduction of EGFP-alpha-actinin binding to the cytoplasmic domain of the beta(1) integrin subunit, but not to actin. Thus, alpha-actinin is essential for the binding of microfilaments to integrins in the FA. CALI-induced changes in alpha-actinin result in the breakage of that link and the subsequent retraction of the stress fibre.
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Affiliation(s)
- Zenon Rajfur
- Department of Cell and Developmental Biology, University of North Carolina, Chapel Hill, NC, USA
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Liu G, Guibao CD, Zheng J. Structural insight into the mechanisms of targeting and signaling of focal adhesion kinase. Mol Cell Biol 2002; 22:2751-60. [PMID: 11909967 PMCID: PMC133741 DOI: 10.1128/mcb.22.8.2751-2760.2002] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Focal adhesion kinase (FAK) is a nonreceptor tyrosine kinase whose focal adhesion targeting (FAT) domain interacts with other focal adhesion molecules in integrin-mediated signaling. Localization of activated FAK to focal adhesions is indispensable for its function. Here we describe a solution structure of the FAT domain bound to a peptide derived from paxillin, a FAK-binding partner. The FAT domain is composed of four helices that form a "right-turn" elongated bundle; the globular fold is mainly maintained by hydrophobic interactions. The bound peptide further stabilizes the structure. Certain signaling events such as phosphorylation and molecule interplay may induce opening of the helix bundle. Such conformational change is proposed to precede departure of FAK from focal adhesions, which starts focal adhesion turnover.
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Affiliation(s)
- Gaohua Liu
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
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Arold ST, Hoellerer MK, Noble MEM. The structural basis of localization and signaling by the focal adhesion targeting domain. Structure 2002; 10:319-27. [PMID: 12005431 DOI: 10.1016/s0969-2126(02)00717-7] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The localization of focal adhesion kinase (FAK) to sites of integrin clustering initiates downstream signaling. The C-terminal focal adhesion targeting (FAT) domain causes this localization by interacting with talin and paxillin. FAT also mediates signaling through Grb2 via phosphorylated Y925. We report two crystal structures of the FAT domain. Large rearrangements of the structure are indicated to allow phosphorylation of Y925 and subsequent interaction with Grb2. Sequence homology and structural compatibility suggest a FAT-like fold for the C-terminal domains of CAS, Efs/Sin, and HEF1. A structure-based alignment including these proteins and the vinculin tail domain reveals a conserved region that could play a role in focal adhesion targeting. Previously postulated "paxillin binding subdomains" may contribute to structural integrity rather than directly to paxillin binding.
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Affiliation(s)
- Stefan T Arold
- Laboratory of Molecular Biophysics, University of Oxford, United Kingdom
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Abstract
Adapter/scaffold proteins, through their multidomain structure, perform a fundamental role in facilitating signal transduction within cells. Paxillin is a focal adhesion adapter protein implicated in growth factor- as well as integrin-mediated signaling pathways. The amino-terminus of paxillin contains five leucine-rich sequences termed LD motifs. These paxillin LD motifs are highly conserved between species as well as within the paxillin superfamily. They mediate interactions with several structural and regulatory proteins important for coordinating changes in the actin cytoskeleton associated with cell motility and cell adhesion as well as in the regulation of gene expression.
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Affiliation(s)
- David A Tumbarello
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210, USA
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Martin KH, Boerner SA, Parsons JT. Regulation of focal adhesion targeting and inhibitory functions of the FAK related protein FRNK using a novel estrogen receptor "switch". CELL MOTILITY AND THE CYTOSKELETON 2002; 51:76-88. [PMID: 11921165 DOI: 10.1002/cm.10018] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Focal adhesion kinase (FAK) is a regulator of numerous adhesion-dependent processes including cell migration, cell proliferation, and cell survival. The C-terminal domain of FAK, FAK-related nonkinase (FRNK), is autonomously expressed and functions as an inhibitor of FAK signaling. Previous attempts to use FRNK as a tool to dissect FAK signaling have been limited because of an inability to temporally regulate the inhibitory functions of FRNK. In this report, we describe and characterize a conditionally targeted form of FRNK that was created by fusing the hormone-binding domain of the estrogen receptor (ER*) to the C-terminus of FRNK. In the absence of added hormone, FRNK-ER* was diffusely distributed throughout the cytoplasm of cells. Upon addition of hormone, the cytoplasmic pool of FRNK-ER* was rapidly redistributed to focal adhesions. We demonstrate that cells expressing FRNK-ER* show a hormone-dependent decrease in FAK tyrosine phosphorylation and cell migration. Furthermore, when cells expressing of FRNK-ER* were treated with hormone, the cells responded with a dramatic change in cell morphology, suggesting a role for FAK in the regulation of the adhesive properties of focal adhesions.
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Affiliation(s)
- Karen H Martin
- Department of Microbiology, University of Virginia Health System, Charlottesville, Virginia 22908, USA
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Mortier E, Cornelissen F, van Hove C, Dillen L, Richardson A. The focal adhesion targeting sequence is the major inhibitory moiety of Fak-related non-kinase. Cell Signal 2001; 13:901-9. [PMID: 11728830 DOI: 10.1016/s0898-6568(01)00226-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Focal adhesion kinase (FAK) plays an important role in integrin-mediated signal transduction pathways and its C-terminal noncatalytic domain Fak-related non-kinase (FRNK), which is autonomously expressed, acts as an inhibitor of FAK. A model has been proposed where FAK and FRNK compete for an essential common binding protein. A FRNK variant in which the direct interaction with v-Crk-associated tyrosine kinase substrate (CAS) was disturbed by point mutations still functioned as an inhibitor of FAK, suggesting that FRNK is unlikely to inhibit FAK by sequestering CAS. Deletion variants of FRNK within the region N-terminal to the focal adhesion targeting (FAT) sequence were still able to inhibit FAK function, indicating that this region is dispensable for the inhibitory effect of FRNK. Overexpression of a green fluorescent protein (GFP) fusion protein containing the FAT sequence delayed cell spreading and reduced FAK tyrosine phosphorylation. This indicates that the FAT sequence is the major inhibitory moiety within FRNK.
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Affiliation(s)
- E Mortier
- Department of Biochemistry, Janssen Research Foundation, Turnhoutseweg 30, B-2340, Beerse, Belgium
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