scholarly journals Dynamic structural order of a low complexity domain facilitates assembly of intermediate filaments

2020 ◽  
Author(s):  
Vasily O. Sysoev ◽  
Masato Kato ◽  
Lillian Sutherland ◽  
Rong Hu ◽  
Steven L. McKnight ◽  
...  
Keyword(s):  
Protein Folding ◽  
Intermediate Filaments ◽  
Cell Morphology ◽  
Intermediate Filament ◽  
Coiled Coil ◽  
Low Complexity ◽  
Tail Domain ◽  
Sequence Complexity ◽  
New Form

AbstractThe coiled-coil domains of intermediate filament (IF) proteins are flanked by regions of low sequence complexity. Whereas IF coiled-coil domains assume dimeric and tetrameric conformations on their own, maturation of eight tetramers into cylindrical IFs is dependent upon either “head” or “tail” domains of low sequence complexity. Here we confirm that the tail domain required for assembly of Drosophila Tm1 IFs functions by forming labile cross-β interactions. These interactions are seen in polymers made from the tail domain alone as well as assembled IFs formed by the intact Tm1 protein. The ability to visualize such interactions in situ within the context of a discrete cellular assembly lends support to the concept that equivalent interactions may be used in organizing other dynamic aspects of cell morphology.One Sentence SummaryA new form of protein folding that interconverts between the structured and unstructured states controls assembly of intermediate filaments.

scholarly journals Dynamic structural order of a low-complexity domain facilitates assembly of intermediate filaments

2020 ◽  
Vol 117 (38) ◽  
pp. 23510-23518
Author(s):  
Vasiliy O. Sysoev ◽  
Masato Kato ◽  
Lillian Sutherland ◽  
Rong Hu ◽  
Steven L. McKnight ◽  
...  
Keyword(s):  
Intermediate Filaments ◽  
Cell Morphology ◽  
Intermediate Filament ◽  
Coiled Coil ◽  
Low Complexity ◽  
Tail Domain ◽  
C Protein ◽  
Sequence Complexity ◽  
Structural Order

The coiled-coil domains of intermediate filament (IF) proteins are flanked by regions of low sequence complexity. Whereas IF coiled-coil domains assume dimeric and tetrameric conformations on their own, maturation of eight tetramers into cylindrical IFs is dependent on either “head” or “tail” domains of low sequence complexity. Here we confirm that the tail domain required for assembly ofDrosophilaTm1-I/C IFs functions by forming labile cross-β interactions. These interactions are seen in polymers made from the tail domain alone, as well as in assembled IFs formed by the intact Tm1-I/C protein. The ability to visualize such interactions in situ within the context of a discrete cellular assembly lends support to the concept that equivalent interactions may be used in organizing other dynamic aspects of cell morphology.

scholarly journals alpha-Internexin, a 66-kD intermediate filament-binding protein from mammalian central nervous tissues.

1985 ◽  
Vol 101 (4) ◽  
pp. 1316-1322 ◽  
Author(s):  
J S Pachter ◽  
R K Liem
Keyword(s):  
Optic Nerve ◽  
Intermediate Filaments ◽  
Intermediate Filament ◽  
Peptide Mapping ◽  
Exchange Chromatography ◽  
Filament Assembly ◽  
Antigen Antibody

In this paper we describe a 66-kD protein that co-purifies with intermediate filaments from rat optic nerve and spinal cord but can be separated further by ion-exchange chromatography. This protein is distinct from the 68-kD neurofilament subunit protein as judged by isoelectric focusing, immunoblotting, peptide mapping, and tests of polymerization competence. This protein is avidly recognized by the monoclonal anti-intermediate filament antigen antibody, previously demonstrated to recognize a common antigenic determinant in all five known classes of intermediate filaments. Also, when isolated this protein binds to various intermediate filament subunit proteins, which suggests an in vivo interaction with the intermediate filament cytoskeleton, and it appears to be axonally transported in the rat optic nerve. Because of this ability to bind to intermediate filaments in situ and in vitro we have named this protein alpha-internexin. A possible functional role for the protein in organizing filament assembly and distribution is discussed.

Plectin: A Cytolinker by Design

1999 ◽  
Vol 380 (2) ◽  
pp. 151-158 ◽  
Author(s):  
F.A. Steinböck ◽  
G. Wiche
Keyword(s):  
Intermediate Filaments ◽  
Intermediate Filament ◽  
Transmembrane Protein ◽  
Coiled Coil ◽  
Cytoskeletal Protein ◽  
Terminal Domain ◽  
Junctional Proteins ◽  
Molecular Backbone ◽  
Cytoskeletal Elements

Abstract Plectin is a cytoskeletal protein of > 500 kDa that forms dumbbell-shaped homodimers comprising a central parallel α-helical coiled coil rod domain flanked by globular domains, thus providing a molecular backbone ideally suited to mediate the protein's interactions with an array of other cytoskeletal elements. Plectin self-associates and interacts with actin and intermediate filament cytoskeleton networks at opposite ends, and it binds at both ends to the hemidesmosomal transmembrane protein integrin beta-4, and likely to other junctional proteins. The central coiled coil rod domain can form bridges over long stretches and serves as a flexible linker between the structurally diverse N-terminal domain and the highly conserved C-terminal domain. Plectin is also a target of p34cdc2 kinase that regulates its dissociation from intermediate filaments during mitosis.

scholarly journals Neurofilaments are obligate heteropolymers in vivo

1993 ◽  
Vol 122 (6) ◽  
pp. 1337-1350 ◽  
Author(s):  
MK Lee ◽  
Z Xu ◽  
PC Wong ◽  
DW Cleveland
Keyword(s):  
Intermediate Filaments ◽  
Intermediate Filament ◽  
Cultured Cells ◽  
Dna Transfection ◽  
Tail Domain ◽  
In Vitro Assembly ◽  
Mature Neurons ◽  
Filament Network

Neurofilaments (NFs), composed of three distinct subunits NF-L, NF-M, and NF-H, are neuron-specific intermediate filaments present in most mature neurons. Using DNA transfection and mice expressing NF transgenes, we find that despite the ability of NF-L alone to assemble into short filaments in vitro NF-L cannot form filament arrays in vivo after expression either in cultured cells or in transgenic oligodendrocytes that otherwise do not contain a cytoplasmic intermediate filament (IF) array. Instead, NF-L aggregates into punctate or sheet like structures. Similar nonfilamentous structures are also formed when NF-M or NF-H is expressed alone. The competence of NF-L to assemble into filaments is fully restored by coexpression of NF-M or NF-H to a level approximately 10% of that of NF-L. Deletion of the head or tail domain of NF-M or substitution of the NF-H tail onto an NF-L subunit reveals that restoration of in vivo NF-L assembly competence requires an interaction provided by the NF-M or NF-H head domains. We conclude that, contrary to the expectation drawn from earlier in vitro assembly studies, NF-L is not sufficient to assemble an extended filament network in an in vivo context and that neurofilaments are obligate heteropolymers requiring NF-L and NF-M or NF-H.

Intermediate filaments: molecular architecture, assembly, dynamics and polymorphism

1999 ◽  
Vol 32 (2) ◽  
pp. 99-187 ◽  
Author(s):  
David A. D. Parry ◽  
Peter M. Steinert
Keyword(s):  
Intermediate Filaments ◽  
Intermediate Filament ◽  
Tertiary Structure ◽  
Quaternary Structure ◽  
Lattice Structure ◽  
Coiled Coil ◽  
Salt Bridges ◽  
Molecular Architecture

1. Introduction 1002. Molecular architecture 1072.1 Primary structure 1082.1.1 Homologous regions 1092.1.2 Chain typing 1152.1.3 Post-translational modifications 1172.2 Secondary structure 1182.2.1 Central rod domain 1182.2.2 Head and tail domains 1192.3 Tertiary structure 1232.3.1 Coiled-coil rod domain 1232.3.1.1 Specificity through salt bridges 1242.3.1.2 Specificity through apolar interactions 1272.3.1.3 A consensus trigger sequence for two-stranded coiled-coils 1282.3.2 Discontinuities in the rod domain 1282.3.2.1 Links 1292.3.2.2 Stutter 1312.3.3 Head and tail domains 1312.4 Electron microscope observations 1333. Assembly 1363.1 Role of the coiled-coil rod domain 1373.2 Role of end domains 1413.3 Experimentally induced crosslinks and modes of assembly 1453.4 Naturally occurring crosslinks for tissue coordination 1543.5 STEM data 1544. Quaternary structure 1604.1 Protofilaments and protofibrils 1604.2 Head and tail domains 1634.3 Surface lattice structure 1644.4 Crystal studies on intermediate filament fragments 1685. Polymorphism 1695.1 Variations on a theme 1705.1.1 Axial structure 1705.1.2 Lateral structure 1716. Keratin intermediate filament chains in diseases 1727. Concluding remarks 1758. Acknowledgments 1769. References 176Three types of intracellular filament have been identified in eukaryotic cells, and together they constitute the key elements of the cytoskeleton. They are the microtubules, the actin-containing microfilaments and the intermediate filaments. The uniqueness of the former two types of filament in cells has been well known for a long time but, in contrast, the intermediate filaments have been a relative new-comer to the scene. The microtubules and the microfilaments have always been easy to distinguish from one another on the grounds of their respective sizes (microtubules are about 25 nm in diameter and microfilaments are about 7–10 nm in diameter). Additionally, microtubules were capable of being disaggregated by the action of colchicine, and microfilaments could be disassembled by other drugs or be decorated with heavy meromyosin to generate arrowhead-like structures. Importantly, in both microtubules and microfilaments the constituent protein subunits were arranged to give the filaments a directionality, and the ability of these filaments to function in vivo depended crucially on this feature of their structure. Microtubules, for example, are involved in mitosis, motility and transport within the cell: each of these functions is clearly a ‘directional’ one. With this background the discovery and characterization of the intermediate filaments can begin.

scholarly journals Affinity to cellulose is a shared property among coiled-coil domains of intermediate filaments and prokaryotic intermediate filament-like proteins

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Niklas Söderholm ◽  
Ala Javadi ◽  
Isabel Sierra Flores ◽  
Klas Flärdh ◽  
Linda Sandblad
Keyword(s):  
Intermediate Filaments ◽  
Intermediate Filament ◽  
Coiled Coil ◽  
Shared Property

Characterization of an Intermediate Filament Protein from the Platyhelminth, Dugesia japonica

2020 ◽  
Vol 27 (5) ◽  
pp. 432-446
Author(s):  
Akiko Yamamoto ◽  
Ken-ichiro Matsunaga ◽  
Toyoaki Anai ◽  
Hitoshi Kawano ◽  
Toshihisa Ueda ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Immunohistochemical Analysis ◽  
Protein Characterization ◽  
Intermediate Filament Protein ◽  
Tail Domain ◽  
Animal Cells ◽  
Dugesia Japonica ◽  
Function Relationship

Background: Intermediate Filaments (IFs) are major constituents of the cytoskeletal systems in animal cells. Objective: To gain insights into the structure-function relationship of invertebrate cytoplasmic IF proteins, we characterized an IF protein from the platyhelminth, Dugesia japonica, termed Dif-1. Method: cDNA cloning, in situ hybridization, immunohistochemical analysis, and IF assembly experiments in vitro using recombinant Dif-1, were performed for protein characterization. Results: The structure deduced from the cDNA sequence showed that Djf-1 comprises 568 amino acids and has a tripartite domain structure (N-terminal head, central rod, and C-terminal tail) that is characteristic of IF proteins. Similar to nuclear IF lamins, Djf-1 contains an extra 42 residues in the coil 1b subdomain of the rod domain that is absent from vertebrate cytoplasmic IF proteins and a nuclear lamin-homology segment of approximately 105 residues in the tail domain; however, it contains no nuclear localization signal. In situ hybridization analysis showed that Djf-1 mRNA is specifically expressed in cells located within the marginal region encircling the worm body. Immunohistochemical analysis showed that Djf-1 protein forms cytoplasmic IFs located close to the microvilli of the cells. In vitro IF assembly experiments using recombinant proteins showed that Djf-1 alone polymerizes into IFs. Deletion of the extra 42 residues in the coil 1b subdomain resulted in the failure of IF formation. Conclusions: Together with data from other histological studies, our results suggest that Djf- 1 is expressed specifically in anchor cells within the glandular adhesive organs of the worm and that Djf-1 IFs may play a role in protecting the cells from mechanical stress.

scholarly journals Caspase Cleavage of Keratin 18 and Reorganization of Intermediate Filaments during Epithelial Cell Apoptosis

1997 ◽  
Vol 138 (6) ◽  
pp. 1379-1394 ◽  
Author(s):  
Carlos Caulín ◽  
Guy S. Salvesen ◽  
Robert G. Oshima
Keyword(s):  
Intermediate Filaments ◽  
Cleavage Site ◽  
Uv Light ◽  
Tail Domain ◽  
Proteolytic Fragment ◽  
Intermediate Filament Proteins ◽  
Caspase Cleavage ◽  
Structural Cell ◽  
Caspase 6

Keratins 8 (K8) and 18 (K18) are major components of intermediate filaments (IFs) of simple epithelial cells and tumors derived from such cells. Structural cell changes during apoptosis are mediated by proteases of the caspase family. During apoptosis, K18 IFs reorganize into granular structures enriched for K18 phosphorylated on serine 53. K18, but not K8, generates a proteolytic fragment during drug- and UV light–induced apoptosis; this fragment comigrates with K18 cleaved in vitro by caspase-6, -3, and -7. K18 is cleaved by caspase-6 into NH2-terminal, 26-kD and COOH-terminal, 22-kD fragments; caspase-3 and -7 additionally cleave the 22-kD fragment into a 19-kD fragment. The cleavage site common for the three caspases was the sequence VEVD/A, located in the conserved L1-2 linker region of K18. The additional site for caspases-3 and -7 that is not cleaved efficiently by caspase-6 is located in the COOH-terminal tail domain of K18. Expression of K18 with alanine instead of serine at position 53 demonstrated that cleavage during apoptosis does not require phosphorylation of serine 53. However, K18 with a glutamate instead of aspartate at position 238 was resistant to proteolysis during apoptosis. Furthermore, this cleavage site mutant appears to cause keratin filament reorganization in stably transfected clones. The identification of the L1-2 caspase cleavage site, and the conservation of the same or very similar sites in multiple other intermediate filament proteins, suggests that the processing of IFs during apoptosis may be initiated by a similar caspase cleavage.

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