Structural basis of filamin A functions

Filamin A (FLNa) can effect orthogonal branching of F-actin and bind many cellular constituents. FLNa dimeric subunits have N-terminal spectrin family F-actin binding domains (ABDs) and an elongated flexible segment of 24 immunoglobulin (Ig) repeats. We generated a library of FLNa fragments to examine their F-actin binding to define the structural properties of FLNa that enable its various functions. We find that Ig repeats 9–15 contain an F-actin–binding domain necessary for high avidity F-actin binding. Ig repeats 16–24, where most FLNa-binding partners interact, do not bind F-actin, and thus F-actin does not compete with Ig repeat 23 ligand, FilGAP. Ig repeats 16–24 have a compact structure that suggests their unfolding may accommodate pre-stress–mediated stiffening of F-actin networks, partner binding, mechanosensing, and mechanoprotection properties of FLNa. Our results also establish the orientation of FLNa dimers in F-actin branching. Dimerization, mediated by FLNa Ig repeat 24, accounts for rigid high-angle FLNa/F-actin branching resistant to bending by thermal forces, and high avidity F-actin binding and cross-linking.

[1]  Ilkka Kilpeläinen,et al.  The structure of the GPIb-filamin A complex. , 2006, Blood.

[2]  P. Janmey,et al.  Tissue Cells Feel and Respond to the Stiffness of Their Substrate , 2005, Science.

[3]  M. D'Addario,et al.  Cell Death and Mechanoprotection by Filamin A in Connective Tissues after Challenge by Applied Tensile Forces* , 2002, The Journal of Biological Chemistry.

[4]  J. Ervasti,et al.  A Cluster of Basic Repeats in the Dystrophin Rod Domain Binds F-actin through an Electrostatic Interaction* , 1998, The Journal of Biological Chemistry.

[5]  J. Hartwig,et al.  Structure of macrophage actin-binding protein molecules in solution and interacting with actin filaments. , 1981, Journal of molecular biology.

[6]  S. Robertson.  Filamin A: phenotypic diversity. , 2005, Current opinion in genetics & development.

[7]  Alex J Levine,et al.  Unfolding cross-linkers as rheology regulators in F-actin networks. , 2007, Physical review. E, Statistical, nonlinear, and soft matter physics.

[8]  J. Hartwig,et al.  Ca2+ and Calmodulin Regulate the Binding of Filamin A to Actin Filaments* , 2005, Journal of Biological Chemistry.

[9]  I. M. Klotz,et al.  Properties of graphical representations of multiple classes of binding sites. , 1971, Biochemistry.

[10]  J. Hartwig,et al.  Actin-binding proteins. , 1991, Current opinion in cell biology.

[11]  K. Jacobson,et al.  Direct interaction with filamins modulates the stability and plasma membrane expression of CFTR. , 2007, The Journal of clinical investigation.

[12]  J. Hartwig,et al.  Actin-binding protein promotes the bipolar and perpendicular branching of actin filaments , 1980, The Journal of cell biology.

[13]  C. Walsh,et al.  The many faces of filamin: A versatile molecular scaffold for cell motility and signalling , 2004, Nature Cell Biology.

[14]  P. Butler,et al.  Structural basis for vertebrate filamin dimerization. , 2005, Structure.

[15]  J. Hartwig,et al.  FilGAP, a Rho- and ROCK-regulated GAP for Rac binds filamin A to control actin remodelling , 2006, Nature Cell Biology.

[16]  J. Hartwig,et al.  Cytoskeletal Protein ABP-280 Directs the Intracellular Trafficking of Furin and Modulates Proprotein Processing in the Endocytic Pathway , 1997, The Journal of cell biology.

[17]  P. Matsudaira,et al.  Actin crosslinking proteins at the leading edge. , 1994, Seminars in cell biology.

[18]  Charles E. Schwartz,et al.  Localized mutations in the gene encoding the cytoskeletal protein filamin A cause diverse malformations in humans , 2003, Nature Genetics.

[19]  J. Hartwig,et al.  Filamins as integrators of cell mechanics and signalling , 2001, Nature Reviews Molecular Cell Biology.

[20]  J. Hartwig,et al.  The architecture of actin filaments and the ultrastructural location of actin-binding protein in the periphery of lung macrophages , 1986, The Journal of cell biology.

[21]  W. H. Goldmann,et al.  Analysis of filamin and α‐actinin binding to actin by the stopped flow method , 1993 .

[22]  Jonathan M. Lee,et al.  Cyclin B1/Cdk1 binds and phosphorylates Filamin A and regulates its ability to cross‐link actin , 2007, FEBS letters.

[23]  D. Branton,et al.  Structural comparison of several actin-binding macromolecules , 1980, The Journal of cell biology.

[24]  T. Holak,et al.  Filamins: promiscuous organizers of the cytoskeleton. , 2006, Trends in biochemical sciences.

[25]  J. Hartwig,et al.  Ca2+ control of actin filament length. Effects of macrophage gelsolin on actin polymerization. , 1981, The Journal of biological chemistry.

[26]  M. Schliwa,et al.  Stabilization and the cytoplasmic ground substance in detergent-opened cells and a structural and biochemical analysis of its composition. , 1981, Proceedings of the National Academy of Sciences of the United States of America.

[27]  J. Hartwig,et al.  Thrombin-induced GPIb-IX centralization on the platelet surface requires actin assembly and myosin II activation. , 1996, Blood.

[28]  B. Jockusch,et al.  The F-actin Cross-linking and Focal Adhesion Protein Filamin A Is a Ligand and in Vivo Substrate for Protein Kinase Cα* , 2003, Journal of Biological Chemistry.

[29]  P. Amrein,et al.  Three-dimensional structure of actin filaments and of an actin gel made with actin-binding protein , 1983, Journal of Cell Biology.

[30]  J H Hartwig,et al.  Human endothelial actin-binding protein (ABP-280, nonmuscle filamin): a molecular leaf spring , 1990, The Journal of cell biology.

[31]  V. Rybin,et al.  Crystal structure of human filamin C domain 23 and small angle scattering model for filamin C 23-24 dimer. , 2007, Journal of molecular biology.

[32]  D A Weitz,et al.  Prestressed F-actin networks cross-linked by hinged filamins replicate mechanical properties of cells. , 2006, Proceedings of the National Academy of Sciences of the United States of America.

[33]  Olli T Pentikäinen,et al.  Structure of three tandem filamin domains reveals auto-inhibition of ligand binding , 2007, The EMBO journal.

[34]  J. Trochu,et al.  Mutations in the Gene Encoding Filamin A as a Cause for Familial Cardiac Valvular Dystrophy , 2006, Circulation.

[35]  I. Campbell,et al.  The molecular basis of filamin binding to integrins and competition with talin. , 2006, Molecular cell.

[36]  J. Hartwig,et al.  Filamin A, the Arp2/3 complex, and the morphology and function of cortical actin filaments in human melanoma cells , 2001, The Journal of cell biology.

[37]  Luis Vidali,et al.  Filamin A (FLNA) is required for cell–cell contact in vascular development and cardiac morphogenesis , 2006, Proceedings of the National Academy of Sciences.

[38]  D. Erle,et al.  Integrin β Cytoplasmic Domains Differentially Bind to Cytoskeletal Proteins* , 1998, The Journal of Biological Chemistry.

[39]  P. Janmey,et al.  Comparison of Filamin A-induced Cross-linking and Arp2/3 Complex-mediated Branching on the Mechanics of Actin Filaments* 210 , 2002, The Journal of Biological Chemistry.

[40]  T. Tanaka,et al.  The role of tropomyosin in the interactions of F-actin with caldesmon and actin-binding protein (or filamin). , 1987, European journal of biochemistry.

[41]  S. Cross,et al.  Cardiac malformations and midline skeletal defects in mice lacking filamin A. , 2006, Human molecular genetics.

[42]  C. Herberhold,et al.  The repeating segments of the F-actin cross-linking gelation factor (ABP-120) have an immunoglobulin-like fold , 1997, Nature Structural Biology.

[43]  R. Huber,et al.  Molecular structure of the rod domain of dictyostelium filamin. , 2004, Journal of molecular biology.

[44]  R. Ezzell,et al.  Direct interaction of filamin (ABP-280) with the beta 2-integrin subunit CD18. , 1995, Journal of immunology.

[45]  L. Tuosto,et al.  CD28 interaction with filamin-A controls lipid raft accumulation at the T-cell immunological synapse , 2006, Nature Cell Biology.

[46]  R. J. Ferland,et al.  Periventricular nodular heterotopia and Williams syndrome , 2006, American journal of medical genetics. Part A.

[47]  T. Steck,et al.  Length distribution of F-actin in Dictyostelium discoideum. , 1990, The Journal of biological chemistry.