1
|
Labus J, Tang K, Henklein P, Krüger U, Hofmann A, Hondke S, Wöltje K, Freund C, Lucka L, Danker K. The α 1 integrin cytoplasmic tail interacts with phosphoinositides and interferes with Akt activation. Biochim Biophys Acta Biomembr 2024; 1866:184257. [PMID: 37992949 DOI: 10.1016/j.bbamem.2023.184257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 11/03/2023] [Accepted: 11/14/2023] [Indexed: 11/24/2023]
Abstract
Integrin α1β1 is an adhesion receptor that binds to collagen and laminin. It regulates cell adhesion, cytoskeletal organization, and migration. The cytoplasmic tail of the α1 subunit consists of 15 amino acids and contains six positively charged lysine residues. In this study, we present evidence that the α1 integrin cytoplasmic tail (α1CT) directly associates with phosphoinositides, preferentially with phosphatidylinositol 3,4,5-trisphosphate (PI(3,4,5)P3). Since the association was disrupted by calcium, magnesium and phosphate ions, this interaction appears to be in ionic nature. Here, the peptide-lipid interaction was driven by the conserved KIGFFKR motif. The exchange of both two potential phospholipid-binding lysines for glycines in the KIGFFKR motif increased α1β1 integrin-specific adhesion and F-actin cytoskeleton formation compared to cells expressing the unmodified α1 subunit, whereas only mutation of the second lysine at position 1171 increased levels of constitutively active α1β1 integrins on the cell surface. In addition, enhanced focal adhesion formation and increased phosphorylation of focal adhesion kinase, but decreased phosphorylation of AKT was observed in these cells. We conclude that the KIGFFKR motif, and in particular lysine1171 is involved in the dynamic regulation of α1β1 integrin activity and that the interaction of α1CT with phosphoinositides may contribute to this process.
Collapse
Affiliation(s)
- Josephine Labus
- Institute for Biochemistry, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany; Hannover Medical School, Department of Cellular Neurophysiology, 30625 Hannover, Germany.
| | - Kerstin Tang
- Institute for Biochemistry, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany; Senate Department for Higher Education and Research, Health, Long-Term Care and Gender Equality, Sector Pharmaceuticals and Medical Devices, Oranienstraße 106, 10969 Berlin, Germany.
| | - Petra Henklein
- Institute for Biochemistry, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany.
| | - Ulrike Krüger
- Institute for Biochemistry, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany; BIH Core Facility Genomik, Charité-Universitätsmedizin Berlin, CVK, Charitéplatz 1, 10117 Berlin, Germany.
| | - Andreas Hofmann
- Structural Chemistry Program, Griffith Institute for Drug Discovery, Griffith University, Brisbane, Queensland 4111, Australia; Dept of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia; NRZ-Authent, Max-Rubner-Institut, Bundesforschungsinstitut für Ernährung und Lebensmittel, E.-C.-Baumann-Str. 20, 95326 Kulmbach, Germany.
| | - Sylvia Hondke
- Institute for Biochemistry, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany
| | - Kerstin Wöltje
- Institute for Biochemistry, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany; Charité-Universitätsmedizin Berlin, Med. Klinik m.S. Infektiologie & Pneumologie, Augustenburger Platz 1, 13353 Berlin, Germany.
| | - Christian Freund
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany.
| | - Lothar Lucka
- Institute for Biochemistry, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany.
| | - Kerstin Danker
- Institute for Biochemistry, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany.
| |
Collapse
|
2
|
Chouhan BS, Käpylä J, Denessiouk K, Denesyuk A, Heino J, Johnson MS. Early chordate origin of the vertebrate integrin αI domains. PLoS One 2014; 9:e112064. [PMID: 25409021 PMCID: PMC4237329 DOI: 10.1371/journal.pone.0112064] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 10/11/2014] [Indexed: 12/17/2022] Open
Abstract
Half of the 18 human integrins α subunits have an inserted αI domain yet none have been observed in species that have diverged prior to the appearance of the urochordates (ascidians). The urochordate integrin αI domains are not human orthologues but paralogues, but orthologues of human αI domains extend throughout later-diverging vertebrates and are observed in the bony fish with duplicate isoforms. Here, we report evidence for orthologues of human integrins with αI domains in the agnathostomes (jawless vertebrates) and later diverging species. Sequence comparisons, phylogenetic analyses and molecular modeling show that one nearly full-length sequence from lamprey and two additional fragments include the entire integrin αI domain region, have the hallmarks of collagen-binding integrin αI domains, and we show that the corresponding recombinant proteins recognize the collagen GFOGER motifs in a metal dependent manner, unlike the α1I domain of the ascidian C. intestinalis. The presence of a functional collagen receptor integrin αI domain supports the origin of orthologues of the human integrins with αI domains prior to the earliest diverging extant vertebrates, a domain that has been conserved and diversified throughout the vertebrate lineage.
Collapse
Affiliation(s)
- Bhanupratap Singh Chouhan
- Structural Bioinformatics Laboratory, Biochemistry, Department of Biosciences, Åbo Akademi University, Turku, Finland
| | - Jarmo Käpylä
- Department of Biochemistry, University of Turku, Turku, Finland
| | - Konstantin Denessiouk
- Structural Bioinformatics Laboratory, Biochemistry, Department of Biosciences, Åbo Akademi University, Turku, Finland
| | - Alexander Denesyuk
- Structural Bioinformatics Laboratory, Biochemistry, Department of Biosciences, Åbo Akademi University, Turku, Finland
| | - Jyrki Heino
- Department of Biochemistry, University of Turku, Turku, Finland
| | - Mark S. Johnson
- Structural Bioinformatics Laboratory, Biochemistry, Department of Biosciences, Åbo Akademi University, Turku, Finland
| |
Collapse
|
3
|
Chin YKY, Headey S, Mohanty B, Emsley J, Simpson JS, Scanlon MJ. Assignments of human integrin α1I domain in the apo and Mg²⁺ bound states. Biomol NMR Assign 2014; 8:117-121. [PMID: 23339031 DOI: 10.1007/s12104-013-9465-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 01/12/2013] [Indexed: 06/01/2023]
Abstract
The α1β1 integrin receptor binds to its main extracellular ligand, collagen, through an inserted domain in its α-subunit called the αI domain (αI). αI contains a metal binding site that allows collagen to coordinate to the domain through a divalent metal ion. Here we report the backbone assignments of the apo and Mg(2+) bound state of the isolated human α1I and the chemical shift changes resulting from metal coordination.
Collapse
Affiliation(s)
- Yanni K-Y Chin
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, VIC, 3052, Australia
| | | | | | | | | | | |
Collapse
|
4
|
Chin YKY, Headey SJ, Mohanty B, Patil R, McEwan PA, Swarbrick JD, Mulhern TD, Emsley J, Simpson JS, Scanlon MJ. The structure of integrin α1I domain in complex with a collagen-mimetic peptide. J Biol Chem 2013; 288:36796-809. [PMID: 24187131 PMCID: PMC3873540 DOI: 10.1074/jbc.m113.480251] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 10/04/2013] [Indexed: 11/06/2022] Open
Abstract
We have determined the structure of the human integrin α1I domain bound to a triple-helical collagen peptide. The structure of the α1I-peptide complex was investigated using data from NMR, small angle x-ray scattering, and size exclusion chromatography that were used to generate and validate a model of the complex using the data-driven docking program, HADDOCK (High Ambiguity Driven Biomolecular Docking). The structure revealed that the α1I domain undergoes a major conformational change upon binding of the collagen peptide. This involves a large movement in the C-terminal helix of the αI domain that has been suggested to be the mechanism by which signals are propagated in the intact integrin receptor. The structure suggests a basis for the different binding selectivity observed for the α1I and α2I domains. Mutational data identify residues that contribute to the conformational change observed. Furthermore, small angle x-ray scattering data suggest that at low collagen peptide concentrations the complex exists in equilibrium between a 1:1 and 2:1 α1I-peptide complex.
Collapse
Affiliation(s)
- Yanni K.-Y. Chin
- From Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences and
| | - Stephen J. Headey
- From Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences and
| | - Biswaranjan Mohanty
- From Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences and
- Australian Research Council Centre of Excellence for Coherent X-ray Science, Monash University, Parkville, Victoria 3052, Australia
| | - Rahul Patil
- From Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences and
| | - Paul A. McEwan
- School of Pharmacy, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom, and
| | - James D. Swarbrick
- From Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences and
| | - Terrence D. Mulhern
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria 3010, Australia
| | - Jonas Emsley
- School of Pharmacy, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom, and
| | - Jamie S. Simpson
- From Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences and
| | - Martin J. Scanlon
- From Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences and
- Australian Research Council Centre of Excellence for Coherent X-ray Science, Monash University, Parkville, Victoria 3052, Australia
| |
Collapse
|
5
|
Lai C, Liu X, Tian C, Wu F. Integrin α1 has a long helix, extending from the transmembrane region to the cytoplasmic tail in detergent micelles. PLoS One 2013; 8:e62954. [PMID: 23646163 PMCID: PMC3639902 DOI: 10.1371/journal.pone.0062954] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 03/26/2013] [Indexed: 12/12/2022] Open
Abstract
Integrin proteins are very important adhesion receptors that mediate cell-cell and cell-extracellular matrix interactions. They play essential roles in cell signaling and the regulation of cellular shape, motility, and the cell cycle. Here, the transmembrane and cytoplasmic (TMC) domains of integrin α1 and β1 were over-expressed and purified in detergent micelles. The structure and backbone relaxations of α1-TMC in LDAO micelles were determined and analyzed using solution NMR. A long helix, extending from the transmembrane region to the cytoplasmic tail, was observed in α1-TMC. Structural comparisons of α1-TMC with reported αIIb-TMC domains indicated different conformations in the transmembrane regions and cytoplasmic tails. An NMR titration experiment indicated weak interactions between α1-TMC and β1-TMC through several α1-TMC residues located at its N-terminal juxta-transmembrane region and C-terminal extended helix region.
Collapse
Affiliation(s)
- Chaohua Lai
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China
| | - Xiaoxi Liu
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China
| | - Changlin Tian
- Hefei National Laboratory for Physical Science at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui, China
- * E-mail: (CT); (FW)
| | - Fangming Wu
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui, China
- * E-mail: (CT); (FW)
| |
Collapse
|
6
|
Weinreb PH, Li S, Gao SX, Liu T, Pepinsky RB, Caravella JA, Lee JH, Woods VL. Dynamic structural changes are observed upon collagen and metal ion binding to the integrin α1 I domain. J Biol Chem 2012; 287:32897-912. [PMID: 22847004 PMCID: PMC3463359 DOI: 10.1074/jbc.m112.354365] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Revised: 07/11/2012] [Indexed: 02/05/2023] Open
Abstract
We have applied hydrogen-deuterium exchange mass spectrometry, in conjunction with differential scanning calorimetry and protein stability analysis, to examine solution dynamics of the integrin α1 I domain induced by the binding of divalent cations, full-length type IV collagen, or a function-blocking monoclonal antibody. These studies revealed features of integrin activation and α1I-ligand complexes that were not detected by static crystallographic data. Mg(2+) and Mn(2+) stabilized α1I but differed in their effects on exchange rates in the αC helix. Ca(2+) impacted α1I conformational dynamics without altering its gross thermal stability. Interaction with collagen affected the exchange rates in just one of three metal ion-dependent adhesion site (MIDAS) loops, suggesting that MIDAS loop 2 plays a primary role in mediating ligand binding. Collagen also induced changes consistent with increased unfolding in both the αC and allosteric C-terminal helices of α1I. The antibody AQC2, which binds to α1I in a ligand-mimetic manner, also reduced exchange in MIDAS loop 2 and increased exchange in αC, but it did not impact the C-terminal region. This is the first study to directly demonstrate the conformational changes induced upon binding of an integrin I domain to a full-length collagen ligand, and it demonstrates the utility of the deuterium exchange mass spectrometry method to study the solution dynamics of integrin/ligand and integrin/metal ion interactions. Based on the ligand and metal ion binding data, we propose a model for collagen-binding integrin activation that explains the differing abilities of Mg(2+), Mn(2+), and Ca(2+) to activate I domain-containing integrins.
Collapse
Affiliation(s)
| | - Sheng Li
- the Department of Medicine and Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, California 92093-0656
| | - Sharon X. Gao
- From Biogen Idec, Inc., Cambridge, Massachusetts 02142 and
| | - Tong Liu
- the Department of Medicine and Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, California 92093-0656
| | | | | | - Jun H. Lee
- the Department of Medicine and Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, California 92093-0656
| | - Virgil L. Woods
- the Department of Medicine and Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, California 92093-0656
| |
Collapse
|
7
|
Lahti M, Bligt E, Niskanen H, Parkash V, Brandt AM, Jokinen J, Patrikainen P, Käpylä J, Heino J, Salminen TA. Structure of collagen receptor integrin α(1)I domain carrying the activating mutation E317A. J Biol Chem 2011; 286:43343-51. [PMID: 22030389 PMCID: PMC3234817 DOI: 10.1074/jbc.m111.261909] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Revised: 10/07/2011] [Indexed: 11/06/2022] Open
Abstract
We have analyzed the structure and function of the integrin α(1)I domain harboring a gain-of-function mutation E317A. To promote protein crystallization, a double variant with an additional C139S mutation was used. In cell adhesion assays, the E317A mutation promoted binding to collagen. Similarly, the double mutation C139S/E317A increased adhesion compared with C139S alone. Furthermore, soluble α(1)I C139S/E317A was a higher avidity collagen binder than α(1)I C139S, indicating that the double variant represents an activated form. The crystal structure of the activated variant of α(1)I was solved at 1.9 Å resolution. The E317A mutation results in the unwinding of the αC helix, but the metal ion has moved toward loop 1, instead of loop 2 in the open α(2)I. Furthermore, unlike in the closed αI domains, the metal ion is pentacoordinated and, thus, prepared for ligand binding. Helix 7, which has moved downward in the open α(2)I structure, has not changed its position in the activated α(1)I variant. During the integrin activation, Glu(335) on helix 7 binds to the metal ion at the metal ion-dependent adhesion site (MIDAS) of the β(1) subunit. Interestingly, in our cell adhesion assays E317A could activate collagen binding even after mutating Glu(335). This indicates that the stabilization of helix 7 into its downward position is not required if the α(1) MIDAS is already open. To conclude, the activated α(1)I domain represents a novel conformation of the αI domain, mimicking the structural state where the Arg(287)-Glu(317) ion pair has just broken during the integrin activation.
Collapse
Affiliation(s)
- Matti Lahti
- From the Department of Biochemistry and Food Chemistry, University of Turku, Turku FI-20014, Finland and
| | - Eva Bligt
- the Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, Turku FI-20520, Finland
| | - Henri Niskanen
- From the Department of Biochemistry and Food Chemistry, University of Turku, Turku FI-20014, Finland and
| | - Vimal Parkash
- the Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, Turku FI-20520, Finland
| | - Anna-Maria Brandt
- the Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, Turku FI-20520, Finland
| | - Johanna Jokinen
- From the Department of Biochemistry and Food Chemistry, University of Turku, Turku FI-20014, Finland and
| | - Pekka Patrikainen
- From the Department of Biochemistry and Food Chemistry, University of Turku, Turku FI-20014, Finland and
| | - Jarmo Käpylä
- From the Department of Biochemistry and Food Chemistry, University of Turku, Turku FI-20014, Finland and
| | - Jyrki Heino
- From the Department of Biochemistry and Food Chemistry, University of Turku, Turku FI-20014, Finland and
| | - Tiina A. Salminen
- the Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, Turku FI-20520, Finland
| |
Collapse
|
8
|
Seo N, Russell BH, Rivera JJ, Liang X, Xu X, Afshar-Kharghan V, Höök M. An engineered alpha1 integrin-binding collagenous sequence. J Biol Chem 2010; 285:31046-54. [PMID: 20675378 PMCID: PMC2945595 DOI: 10.1074/jbc.m110.151357] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Indexed: 01/15/2023] Open
Abstract
Collagen is an extracellular matrix structural component that can regulate cellular processes through its interaction with the integrins, α1β1, α2β1, α10β1, and α11β1. Collagen-like proteins have been identified in a number of bacterial species. Here, we used Scl2 from Streptococcus pyogenes serotype M28 strain MGAS6274 as a backbone for the introduction of discrete integrin-binding sequences. The introduced sequences GLPGER, GFPGER, or GFPGEN did not affect triple helix stability of the Scl (Streptococcal collagen-like) protein. Using ELISA and surface plasmon resonance, we determined that Scl2(GLPGER) and Scl2(GFPGER) bound to recombinant human α1 and α2 I-domains in a metal ion-dependent manner and without a requirement for hydroxyproline. We predicted a novel and selective integrin-binding sequence, GFPGEN, through the use of computer modeling and demonstrated that Scl2(GFPGEN) shows specificity toward the α1 I-domain and does not bind the α2 I-domain. Using C2C12 cells, we determined that intact integrins interact with the modified Scl2 proteins with the same selectivity as recombinant I-domains. These modified Scl2 proteins also acted as cell attachment substrates for fibroblast, endothelial, and smooth muscle cells. However, the modified Scl2 proteins were unable to aggregate platelets. These results indicate that Scl2 is a suitable backbone for the introduction of mammalian integrin-binding sequences, and these sequences may be manipulated to individually target α1β1 and α2β1.
Collapse
Affiliation(s)
- Neungseon Seo
- From the Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M University System Health Science Center, Houston, Texas 77030 and
| | - Brooke H. Russell
- From the Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M University System Health Science Center, Houston, Texas 77030 and
| | - Jose J. Rivera
- From the Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M University System Health Science Center, Houston, Texas 77030 and
| | - Xiaowen Liang
- From the Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M University System Health Science Center, Houston, Texas 77030 and
| | - Xuejun Xu
- From the Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M University System Health Science Center, Houston, Texas 77030 and
| | | | - Magnus Höök
- From the Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M University System Health Science Center, Houston, Texas 77030 and
| |
Collapse
|
9
|
Zhuang S, Kelo L, Nardi JB, Kanost MR. Multiple alpha subunits of integrin are involved in cell-mediated responses of the Manduca immune system. Dev Comp Immunol 2008; 32:365-79. [PMID: 17868866 DOI: 10.1016/j.dci.2007.07.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2007] [Revised: 07/27/2007] [Accepted: 07/28/2007] [Indexed: 05/17/2023]
Abstract
The cell-mediated responses of the insect innate immune system-phagocytosis, nodulation, encapsulation-involve multiple cell adhesion molecules of hemocyte surfaces. A hemocyte-specific (HS) integrin and a member of the immunoglobulin (Ig) superfamily (neuroglian) are involved in the encapsulation response of hemocytes in Manduca sexta. In addition, two new integrin alpha (alpha) subunits have been found on these hemocytes. The alpha2 subunit is mainly expressed in epidermis and Malphigian tubules, whereas the alpha3 subunit is primarily expressed on hemocytes and fat body cells. Of the three known alpha subunits, the alpha1 subunit found in HS integrin is the predominant subunit of hemocytes. Cell adhesion assays indicate that alpha2 belongs to the integrin family with RGD-binding motifs, confirming the phylogenetic analysis of alpha subunits based on the amino-acid sequence alignment of different alpha subunits. Double-stranded RNAs (dsRNAs) targeting each of these three integrin alpha subunits not only specifically decreased transcript expression of each alpha subunit in hemocytes, but also abolished the cell-mediated encapsulation response of hemocytes to foreign surfaces. The individual alpha subunits of M. sexta integrins, like their integrin counterparts in mammalian immune systems, have critical, individual roles in cell-substrate and cell-cell interactions during immune responses.
Collapse
Affiliation(s)
- Shufei Zhuang
- Department of Biochemistry, Kansas State University, Manhattan, KS 66506, USA
| | | | | | | |
Collapse
|
10
|
Smerling C, Tang K, Hofmann W, Danker K. Role of the α1 integrin cytoplasmic tail in the formation of focal complexes, actin organization, and in the control of cell migration. Exp Cell Res 2007; 313:3153-65. [PMID: 17632102 DOI: 10.1016/j.yexcr.2007.06.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2007] [Revised: 06/04/2007] [Accepted: 06/05/2007] [Indexed: 10/23/2022]
Abstract
Integrins play a key role in cellular motility; an essential process for embryonic development and tissue morphogenesis, and also for pathological processes such as tumor cell invasion and metastasis. Recently, we showed that the cytoplasmic tail of integrin alpha(1) regulates the formation of focal complexes, F-actin cytoskeleton reorganization, and migration. We now report that the alpha(1) tail directly engages in collagen IV-mediated migration by regulation of the small GTPase Rac1. Deletion variants of the alpha(1) integrin differ in their ability to activate Rac1. Constitutively active Rac1 rescues motility in otherwise immotile cells expressing a truncated alpha(1) integrin without any cytoplasmic tail. In these cells, levels of GTP-Rac1 are constitutively elevated, but kept non-functional in the cytoplasm. The conserved GFFKR motif is sufficient to convey Rac1 activation, but downregulates the amount of GTP-Rac1 in the absence of the alpha(1)-specific sequence PLKKKMEK. This sequence is also required for the recruitment of PI3K to focal adhesions following Rac1 activation. Our results demonstrate that the short alpha(1) cytoplasmic tail is crucial for Rac1 activation and PI3K localization, which in turn results in cytoskeletal rearrangement and subsequent migration.
Collapse
Affiliation(s)
- Christiane Smerling
- Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Institut für Biochemie und Molekularbiologie, Arnimallee 22, D-14195 Berlin-Dahlem, Germany
| | | | | | | |
Collapse
|
11
|
Abstract
The alpha subunit-inserted (I) domain of integrin alphaLbeta2 [lymphocyte function-associated antigen-1 (LFA-1)] binds to intercellular adhesion molecule-1 (ICAM-1). The C- and N-termini of the alpha I domain are near one another on the "lower" face, opposite the metal ion-dependent adhesion site (MIDAS) on the "upper face". In conversion to the open alpha I domain conformation, a 7 A downward, axial displacement of C-terminal helix alpha7 is allosterically linked to rearrangement of the MIDAS into its high-affinity conformation. Here, we test the hypothesis that when an applied force is appropriately linked to conformational change, the conformational change can stabilize adhesive interactions that resist the applied force. Integrin alpha I domains were anchored to the cell surface through their C- or N-termini using type I or II transmembrane domains, respectively. C-terminal but not N-terminal anchorage robustly supported cell rolling on ICAM-1 substrates in shear flow. In contrast, when the alphaL I domain was mutationally stabilized in the open conformation with a disulfide bond, it mediated comparable levels of firm adhesion with type I and type II membrane anchors. To exclude other effects as the source of differential adhesion, these results were replicated using alpha I domains conjugated through the N- or C-terminus to polystyrene microspheres. Our results demonstrate a mechanical feedback system for regulating the strength of an adhesive bond. A review of crystal structures of integrin alpha and beta subunit I domains and selectins in high- and low-affinity conformations demonstrates a common mechanochemical design in which biologically applied tensile force stabilizes the more extended, high-affinity conformation.
Collapse
Affiliation(s)
| | | | | | | | - Timothy A. Springer
- * To whom correspondence should be addressed. E-mail: . Phone: (617) 278-3200. Fax: (617) 278-3232
| |
Collapse
|
12
|
Peng L, Jin G, Wang L, Guo J, Meng L, Shou C. Identification of integrin alpha1 as an interacting protein of protein tyrosine phosphatase PRL-3. Biochem Biophys Res Commun 2006; 342:179-83. [PMID: 16472776 DOI: 10.1016/j.bbrc.2006.01.102] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2006] [Accepted: 01/20/2006] [Indexed: 01/19/2023]
Abstract
PRL-3 is a newly identified protein tyrosine phosphatase associated with tumor metastasis. It is over-expressed in various cancers, such as colorectal cancer, gastric cancer, and ovarian cancer, and is correlated with the progression and survival of cancers. Although PRL-3 plays a causative role in promoting cancer cell invasion and metastasis, the molecular mechanism is unknown. To investigate PRL-3's roles in tumorigenesis and signal transduction pathway, we screened the human placenta brain cDNA library with the bait of PRL-3 in yeast two-hybrid system. Then we identified integrin alpha1 as a PRL-3-interacting protein for the first time, and verified this physical association with pull-down and co-immunoprecipitation assays. Furthermore, we found that PRL-3 could down-regulate the tyrosine-phosphorylation level of integrin beta1 and increased the phosphorylation level of Erk1/2. Our present discovery will provide new clues for elucidating the molecular mechanism of PRL-3 in promoting cancer invasion and metastasis.
Collapse
Affiliation(s)
- Lirong Peng
- Department of Biochemistry and Molecular Biology, Peking University School of Oncology, Beijing Cancer Hospital and Institute, Beijing 100036, PR China
| | | | | | | | | | | |
Collapse
|
13
|
Salas A, Shimaoka M, Kogan AN, Harwood C, von Andrian UH, Springer TA. Rolling adhesion through an extended conformation of integrin alphaLbeta2 and relation to alpha I and beta I-like domain interaction. Immunity 2004; 20:393-406. [PMID: 15084269 DOI: 10.1016/s1074-7613(04)00082-2] [Citation(s) in RCA: 135] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2003] [Revised: 01/16/2004] [Accepted: 02/10/2004] [Indexed: 10/26/2022]
Abstract
In vivo, beta(2) integrins and particularly alpha(L)beta(2) (LFA-1) robustly support firm adhesion of leukocytes, but can also cooperate with other molecules in supporting rolling adhesion. Strikingly, a small molecule alpha/beta I-like allosteric antagonist, XVA143, inhibits LFA-1-dependent firm adhesion, while at the same time it enhances adhesion in shear flow and rolling both in vitro and in vivo. XVA143 appears to induce the extended conformation of integrins as shown by increased activation epitope exposure. Fab to the beta(2) I-like domain converts firm adhesion to rolling adhesion, but does not enhance adhesion. Residue alpha(L)-Glu-310 in the linker following the I domain is critical for communication to the beta(2) I-like domain, rolling, integrin extension, and activation by Mn(2+) of firm adhesion. The results demonstrate the importance of integrin extension in rolling, and suggest that rolling and firm adhesion are mediated by extended conformations of alpha(L)beta(2) that differ in the affinity of the alpha(L) I domain for ICAM-1.
Collapse
Affiliation(s)
- Azucena Salas
- The CBR Institute for Biomedical Research, Department of Pathology, 200 Longwood Avenue, Boston, MA 02115 USA
| | | | | | | | | | | |
Collapse
|
14
|
Bank I, Kapyla J, Grinbaum A, Doolman R, Bank J, Sela BA. Analysis of cell-free human alpha1 integrin with a monoclonal antibody to the I-domain: detection in ocular fluid and function as an adhesion substrate. Cell Commun Adhes 2004; 8:113-23. [PMID: 11936186 DOI: 10.3109/15419060109080711] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The alpha1 beta1 integrin, an inserted (1) domain containing collagen receptor, is expressed in the cell surface membrane of normal and malignant cells, and may play a role in their migration through tissues or in metastatic spread. Here we report that a functional anti-human alpha1beta1 integrin monoclonal antibody (mAb) (1B3.1) directly and specifically binds plastic bound recombinant human alpha1 I-domain protein containing the collagen binding site. Detection was diminished by acidification of the I-domain protein but was enhanced by increasing concentrations of Mg2+ cation. Furthermore, we detected binding of the mAb to proteins from the ocular fluids of 6 patients, with the highest concentration, corresponding to 22.1 ng/ml of I-domain, found in a sample from the eye of a patient with metastatic lung adenocarcinoma. Interestingly, we found that both SKNSH neuroblastoma cells and virally transformed human T cells adhered specifically to plastic wells coated with either immobilized collagen IV or alpha1 I-domain. MAb I B3.1 inhibited adhesion to collagen IV but not to immobilized I-domain. These results suggest a novel function for cell free alpha1 I-domain as a substrate for cellular adhesion, which may have relevance in tumor spread in vivo.
Collapse
Affiliation(s)
- I Bank
- Department of Medicine, Chaim Sheba Medical Center, Tel Hashomer, Israel.
| | | | | | | | | | | |
Collapse
|
15
|
Abstract
Collagen type IV forms a network in the basement membrane into which other constituents of the tissue are incorporated. It also provides cell-adhesion sites that are specifically recognized by cell-surface receptors, i.e., the integrins. Different from the ubiquitous sequential RGD adhesion motif found in most of the matrix proteins, in collagen type IV, the responsible binding sites for alpha1beta1 integrin have been identified as Asp461 of the two alpha1 chains and Arg461 of the alpha2 chain. Because of the heterotrimeric character of this collagen, the spatial geometry of the binding epitope depends not only on the triple-helical fold, but decisively even on the stagger of the chains. To investigate the effects of chain registration on the conformational properties and binding affinities of this adhesion epitope, two synthetic heterotrimeric collagen peptides consisting of the identical three chains were assembled by an artificial cystine knot in two different registers, i.e., in the most plausible alpha2alpha1alpha1' and less probable alpha1alpha2alpha1' chain alignment. A detailed conformational characterization of both trimers allowed to correlate their different binding affinities for alpha1beta1 integrin with the degree of local plasticity of the two different triple helices. Optimal local breathing of the rod-shaped collagens is apparently crucial for selective recognition by proteins interacting with these main components of the extracellular matrix.
Collapse
Affiliation(s)
- Christian Renner
- Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | | | | |
Collapse
|