scholarly journals Structural basis of filamin A functions

2007 ◽  
Vol 179 (5) ◽  
pp. 1011-1025 ◽  
Author(s):  
Fumihiko Nakamura ◽  
Teresia M. Osborn ◽  
Christopher A. Hartemink ◽  
John H. Hartwig ◽  
Thomas P. Stossel
Keyword(s):  
Actin Binding ◽  
Structural Basis ◽  
High Avidity ◽  
Filamin A ◽  
Compact Structure ◽  
Actin Networks ◽  
Binding Domains ◽  
Binding Partners ◽  
Actin Binding Domain ◽  
Flexible Segment

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.

scholarly journals Structural basis of the filamin A actin-binding domain interaction with F-actin

2018 ◽  
Vol 25 (10) ◽  
pp. 918-927 ◽  
Author(s):  
Daniel V. Iwamoto ◽  
Andrew Huehn ◽  
Bertrand Simon ◽  
Clotilde Huet-Calderwood ◽  
Massimiliano Baldassarre ◽  
...  
Keyword(s):  
Binding Domain ◽  
Actin Binding ◽  
Structural Basis ◽  
Filamin A ◽  
Domain Interaction ◽  
Actin Binding Domain

scholarly journals Filamin A Regulates Cardiovascular Remodeling

2021 ◽  
Vol 22 (12) ◽  
pp. 6555
Author(s):  
Sashidar Bandaru ◽  
Chandu Ala ◽  
Alex-Xianghua Zhou ◽  
Levent M. Akyürek
Keyword(s):  
Transcription Factors ◽  
Respiratory Diseases ◽  
Cell Function ◽  
Actin Binding ◽  
Cardiovascular Development ◽  
Filamin A ◽  
Cardiovascular Malformations ◽  
Experimental Animal Models ◽  
Actin Networks ◽  
Cardiovascular Remodeling

Filamin A (FLNA) is a large actin-binding cytoskeletal protein that is important for cell motility by stabilizing actin networks and integrating them with cell membranes. Interestingly, a C-terminal fragment of FLNA can be cleaved off by calpain to stimulate adaptive angiogenesis by transporting multiple transcription factors into the nucleus. Recently, increasing evidence suggests that FLNA participates in the pathogenesis of cardiovascular and respiratory diseases, in which the interaction of FLNA with transcription factors and/or cell signaling molecules dictate the function of vascular cells. Localized FLNA mutations associate with cardiovascular malformations in humans. A lack of FLNA in experimental animal models disrupts cell migration during embryogenesis and causes anomalies, including heart and vessels, similar to human malformations. More recently, it was shown that FLNA mediates the progression of myocardial infarction and atherosclerosis. Thus, these latest findings identify FLNA as an important novel mediator of cardiovascular development and remodeling, and thus a potential target for therapy. In this update, we summarized the literature on filamin biology with regard to cardiovascular cell function.

scholarly journals Control of microtubule dynamics using an optogenetic microtubule plus end–F-actin cross-linker

2017 ◽  
Vol 217 (2) ◽  
pp. 779-793 ◽  
Author(s):  
Rebecca C. Adikes ◽  
Ryan A. Hallett ◽  
Brian F. Saway ◽  
Brian Kuhlman ◽  
Kevin C. Slep
Keyword(s):  
Blue Light ◽  
Actin Binding ◽  
Cross Linking ◽  
Dependent Manner ◽  
Exclusion Zone ◽  
Actin Networks ◽  
Drosophila Melanogaster S2 Cells ◽  
Actin Binding Domain ◽  
Specific Factors ◽  
Insight Into

We developed a novel optogenetic tool, SxIP–improved light-inducible dimer (iLID), to facilitate the reversible recruitment of factors to microtubule (MT) plus ends in an end-binding protein–dependent manner using blue light. We show that SxIP-iLID can track MT plus ends and recruit tgRFP-SspB upon blue light activation. We used this system to investigate the effects of cross-linking MT plus ends and F-actin in Drosophila melanogaster S2 cells to gain insight into spectraplakin function and mechanism. We show that SxIP-iLID can be used to temporally recruit an F-actin binding domain to MT plus ends and cross-link the MT and F-actin networks. Cross-linking decreases MT growth velocities and generates a peripheral MT exclusion zone. SxIP-iLID facilitates the general recruitment of specific factors to MT plus ends with temporal control enabling researchers to systematically regulate MT plus end dynamics and probe MT plus end function in many biological processes.

scholarly journals Binding partner- and force-promoted changes in αE-catenin conformation probed by native cysteine labeling

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ksenia Terekhova ◽  
Sabine Pokutta ◽  
Yee S. Kee ◽  
Jing Li ◽  
Emad Tajkhorshid ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Binding Protein ◽  
Binding Domain ◽  
Actin Binding ◽  
Titration Calorimetry ◽  
Allosteric Coupling ◽  
Actin Binding Protein ◽  
Binding Partners ◽  
Actin Binding Domain ◽  
Cysteine Labeling

Abstract Adherens Junctions (AJs) are cell-cell adhesion complexes that sense and propagate mechanical forces by coupling cadherins to the actin cytoskeleton via β-catenin and the F-actin binding protein αE-catenin. When subjected to mechanical force, the cadherin•catenin complex can tightly link to F-actin through αE-catenin, and also recruits the F-actin-binding protein vinculin. In this study, labeling of native cysteines combined with mass spectrometry revealed conformational changes in αE-catenin upon binding to the E-cadherin•β-catenin complex, vinculin and F-actin. A method to apply physiologically meaningful forces in solution revealed force-induced conformational changes in αE-catenin when bound to F-actin. Comparisons of wild-type αE-catenin and a mutant with enhanced vinculin affinity using cysteine labeling and isothermal titration calorimetry provide evidence for allosteric coupling of the N-terminal β-catenin-binding and the middle (M) vinculin-binding domain of αE-catenin. Cysteine labeling also revealed possible crosstalk between the actin-binding domain and the rest of the protein. The data provide insight into how binding partners and mechanical stress can regulate the conformation of full-length αE-catenin, and identify the M domain as a key transmitter of conformational changes.

scholarly journals Evidence for functional homology in the F-actin binding domains of gelsolin and alpha-actinin: implications for the requirements of severing and capping.

1992 ◽  
Vol 119 (4) ◽  
pp. 835-842 ◽  
Author(s):  
M Way ◽  
B Pope ◽  
A G Weeds
Keyword(s):  
Calcium Ions ◽  
Actin Filaments ◽  
Tandem Repeats ◽  
Actin Binding ◽  
Binding Affinities ◽  
Binding Domains ◽  
Functional Homology ◽  
Actin Binding Domain ◽  
Extended Sequence ◽  
Actin Binding Site

The F-actin binding domains of gelsolin and alpha-actinin compete for the same site on actin filaments with similar binding affinities. Both contain tandem repeats of approximately 125 amino acids, the first of which is shown to contain the actin-binding site. We have replaced the F-actin binding domain in the NH2-terminal half of gelsolin by that of alpha-actinin. The hybrid severs filaments almost as efficiently as does gelsolin or its NH2-terminal half, but unlike the latter, requires calcium ions. The hybrid binds two actin monomers and caps the barbed ends of filaments in the presence or absence of calcium. The cap produced by the hybrid binds with lower affinity than that of gelsolin and is not stable: It dissociates from filament ends with a half life of approximately 15 min. Although there is no extended sequence homology between these two different F-actin binding domains, our experiments show that they are functionally equivalent and provide new insights into the mechanism of microfilament severing.

scholarly journals The BPAG1 locus

2001 ◽  
Vol 154 (4) ◽  
pp. 691-698 ◽  
Author(s):  
Conrad L. Leung ◽  
Min Zheng ◽  
Susan M. Prater ◽  
Ronald K.H. Liem
Keyword(s):  
Coiled Coil ◽  
Binding Domain ◽  
Mutant Mice ◽  
Actin Binding ◽  
Spectrin Repeat ◽  
Binding Domains ◽  
Microtubule Binding Domain ◽  
Actin Binding Domain ◽  
Skin Fragility ◽  
Interaction Domains

Bullous pemphigoid antigen 1 (BPAG1) is a member of the plakin family with cytoskeletal linker properties. Mutations in BPAG1 cause sensory neuron degeneration and skin fragility in mice. We have analyzed the BPAG1 locus in detail and found that it encodes different interaction domains that are combined in tissue-specific manners. These domains include an actin-binding domain (ABD), a plakin domain, a coiled coil (CC) rod domain, two different potential intermediate filament–binding domains (IFBDs), a spectrin repeat (SR)-containing rod domain, and a microtubule-binding domain (MTBD). There are at least three major forms of BPAG1: BPAG1-e (302 kD), BPAG1-a (615 kD), and BPAG1-b (834 kD). BPAG1-e has been described previously and consists of the plakin domain, the CC rod domain, and the first IFBD. It is the primary epidermal BPAG1 isoform, and its absence that is the likely cause of skin fragility in mutant mice. BPAG1-a is the major isoform in the nervous system and a homologue of the microtubule actin cross-linking factor, MACF. BPAG1-a is composed of the ABD, the plakin domain, the SR-containing rod domain, and the MTBD. The absence of BPAG1-a is the likely cause of sensory neurodegeneration in mutant mice. BPAG1-b is highly expressed in muscles, and has extra exons encoding a second IFBD between the plakin and SR-containing rod domains of BPAG1-a.

scholarly journals Structure and Function of Filamin C in the Muscle Z-Disc

2020 ◽  
Vol 21 (8) ◽  
pp. 2696 ◽  
Author(s):  
Zhenfeng Mao ◽  
Fumihiko Nakamura
Keyword(s):  
Sequence Similarity ◽  
Actin Binding ◽  
Amino Acid Residues ◽  
Filamin A ◽  
Dimerization Domain ◽  
High Sequence Similarity ◽  
Actin Binding Domain ◽  
And Function ◽  
Filamin C

Filamin C (FLNC) is one of three filamin proteins (Filamin A (FLNA), Filamin B (FLNB), and FLNC) that cross-link actin filaments and interact with numerous binding partners. FLNC consists of a N-terminal actin-binding domain followed by 24 immunoglobulin-like repeats with two intervening calpain-sensitive hinges separating R15 and R16 (hinge 1) and R23 and R24 (hinge-2). The FLNC subunit is dimerized through R24 and calpain cleaves off the dimerization domain to regulate mobility of the FLNC subunit. FLNC is localized in the Z-disc due to the unique insertion of 82 amino acid residues in repeat 20 and necessary for normal Z-disc formation that connect sarcomeres. Since phosphorylation of FLNC by PKC diminishes the calpain sensitivity, assembly, and disassembly of the Z-disc may be regulated by phosphorylation of FLNC. Mutations of FLNC result in cardiomyopathy and muscle weakness. Although this review will focus on the current understanding of FLNC structure and functions in muscle, we will also discuss other filamins because they share high sequence similarity and are better characterized. We will also discuss a possible role of FLNC as a mechanosensor during muscle contraction.

scholarly journals Control of microtubule dynamics using an optogenetic microtubule plus end–F-actin cross-linker

2017 ◽  
Author(s):  
Rebecca C. Adikes ◽  
Ryan A. Hallett ◽  
Brian F. Saway ◽  
Brian Kuhlman ◽  
Kevin C. Slep
Keyword(s):  
Blue Light ◽  
Microtubule Dynamics ◽  
Actin Binding ◽  
Cross Linking ◽  
Dependent Manner ◽  
Exclusion Zone ◽  
Actin Networks ◽  
Actin Binding Domain ◽  
Specific Factors

AbstractWe developed a novel optogenetic tool, SxIP-iLID, to facilitate the reversible recruitment of factors to microtubule (MT) plus ends in an End Binding (EB) protein-dependent manner using blue light. We show that SxIP-iLID can track MT plus ends and recruit tgRFP-SspB upon blue light activation. We then used this system to investigate the effects of cross-linking MT plus ends and F-actin in Drosophila S2 cells to gain insight into spectraplakin function and mechanism. We show that SxIP-iLID can be used to temporally recruit a F-actin binding domain to MT plus ends and cross-link the MT and F-actin networks. Light-mediated MT-F-actin cross-linking decreases MT growth velocities and generates a MT exclusion zone in the lamella. SxIP-iLID facilitates the general recruitment of specific factors to MT plus ends with temporal control enabling researchers to systematically regulate MT plus end dynamics and probe MT plus end function in many biological processes.SummarySxIP-iLID is a novel optogenetic tool designed to assess the spatiotemporal role of proteins on microtubule dynamics. We establish that optogenetic cross-linking of microtubule and actin networks decreases MT growth velocities and increases the cell area void of microtubules.

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