scholarly journals Human keratin 1/10‐1B tetramer structures reveal a knob‐pocket mechanism in intermediate filament assembly

2019 ◽  
Vol 38 (11) ◽  
Author(s):  
Sherif A Eldirany ◽  
Minh Ho ◽  
Alexander J Hinbest ◽  
Ivan B Lomakin ◽  
Christopher G Bunick
Keyword(s):  
Intermediate Filament ◽  
Filament Assembly ◽  
Keratin 1

Mutations in the non-helical linker segment L1-2 of keratin 5 in patients with Weber-Cockayne epidermolysis bullosa simplex

1994 ◽  
Vol 107 (4) ◽  
pp. 765-774
Author(s):  
Y.M. Chan ◽  
Q.C. Yu ◽  
J. LeBlanc-Straceski ◽  
A. Christiano ◽  
L. Pulkkinen ◽  
...  
Keyword(s):  
Epidermolysis Bullosa ◽  
Intermediate Filament ◽  
Point Mutations ◽  
Epidermolysis Bullosa Simplex ◽  
Keratin Gene ◽  
Filament Assembly ◽  
Keratin Polypeptides ◽  
Epidermolytic Hyperkeratosis ◽  
Hands And Feet ◽  
Linker Segment

Keratins are the major structural proteins of the epidermis. Analyzing keratin gene sequences, appreciating the switch in keratin gene expression that takes place as epidermal cells commit to terminally differentiate, and elucidating how keratins assemble into 10 nm filaments, have provided the foundation that has led to the discoveries of the genetic bases of two major classes of human skin diseases, epidermolysis bullosa simplex (EBS) and epidermolytic hyperkeratosis (EH). These diseases involve point mutations in either the basal epidermal keratin pair, K5 and K14 (EBS), or the suprabasal pair, K1 and K10 (EH). In severe cases of EBS and EH, mutations are found in the highly conserved ends of the alpha-helical rod domain, regions that, by random mutagenesis, had already been found to be important for 10 nm filament assembly. In order to identify regions of the keratin polypeptides that might be more subtly involved in 10 nm filament assembly and to explore the diversity in mutations within milder cases of these diseases, we have focused on Weber-Cockayne EBS, where mild blistering occurs primarily on the hands and feet in response to mechanical stress. In this report, we show that affected members of two different W-C EBS families have point mutations within 1 residue of each other in the non-helical linker segment of the K5 polypeptide. Genetic linkage analyses, the absence of this mutation in > 150 wild-type alleles and filament assembly studies suggest that these mutations are responsible for the W-C EBS phenotype. These findings provide the best evidence to date that the non-helical linker region in the middle of the keratin polypeptides plays a subtle but significant role in intermediate filament structure and/or intermediate filament cytoskeletal architecture.

Peripherin assembles into homopolymers in SW13 cells

1995 ◽  
Vol 108 (10) ◽  
pp. 3279-3284 ◽  
Author(s):  
C. Cui ◽  
P.J. Stambrook ◽  
L.M. Parysek
Keyword(s):  
Intermediate Filament ◽  
Network Formation ◽  
Full Length ◽  
Intermediate Filament Proteins ◽  
Filament Assembly ◽  
Mature Neurons ◽  
Carboxyl Terminal ◽  
Relationship Of ◽  
Filament Network ◽  
Carboxyl Tail

The properties of full-length and mutant peripherins were studied in intermediate filament-less SW13 cells to define regions of peripherin that are essential for initiation of filament assembly. A full-length rat peripherin gene transfected into SW13 cells resulted in filament formation, consistent with the close structural relationship of peripherin to other type III intermediate filament proteins that readily form homopolymers. Translation of full-length rat peripherin is initiated predominantly at the second of two inframe AUGs. Deletions within the amino terminus of wild-type peripherin abolished its ability to form filaments in SW13 cells. In contrast, deletion of the entire carboxyl-terminal tail of peripherin did not affect its ability to form filamentous arrays in transfected SW13 cells. These results indicate that, of the intermediate filament proteins that are expressed in mature neurons, only peripherin and alpha-internexin are capable of making homopolymer intermediate filaments. In addition, mutations of the carboxyl tail of peripherin generally do not interfere with filament network formation.

scholarly journals Completion of the Vimentin Rod Domain Structure Using Experimental Restraints: A New Tool for Exploring Intermediate Filament Assembly and Mutations

Structure ◽  
2019 ◽  
Vol 27 (10) ◽  
pp. 1547-1560.e4 ◽  
Author(s):  
David D. Gae ◽  
Madhu S. Budamagunta ◽  
John F. Hess ◽  
Robert M. McCarrick ◽  
Gary A. Lorigan ◽  
...  
Keyword(s):  
Domain Structure ◽  
Intermediate Filament ◽  
Filament Assembly

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.

scholarly journals Chemotactic Peptide-induced Changes of Intermediate Filament Organization in Neutrophils during Granule Secretion: Role of Cyclic Guanosine Monophosphate

1998 ◽  
Vol 9 (10) ◽  
pp. 2933-2947 ◽  
Author(s):  
Katherine B. Pryzwansky ◽  
Elizabeth P. Merricks
Keyword(s):  
Intermediate Filaments ◽  
Intermediate Filament ◽  
Cyclic Guanosine Monophosphate ◽  
Cytochalasin D ◽  
Guanosine Monophosphate ◽  
Microtubule Organization ◽  
Intact Cells ◽  
Filament Assembly ◽  
Dependent Protein ◽  
Granule Secretion

In neutrophils activated to secrete with formyl-methionyl-leucyl-phenylalanine, intermediate filaments are phosphorylated transiently by cyclic guanosine monophosphate (cGMP)-dependent protein kinase (G-kinase). cGMP regulation of vimentin organization was investigated. During granule secretion, cGMP levels were elevated and intermediate filaments were transiently assembled at the pericortex to areas devoid of granules and microfilaments. Microtubule and microfilament inhibitors affected intermediate filament organization, granule secretion, and cGMP levels. Cytochalasin D and nocodazole caused intermediate filaments to assemble at the nucleus, rather than at the pericortex. cGMP levels were elevated in neutrophils by both inhibitors; however, with cytochalasin D, cGMP was elevated earlier and granule secretion was excessive. Nocodazole did not affect normal cGMP elevations, but specific granule secretion was delayed. LY83583, a guanylyl cyclase antagonist, inhibited granule secretion and intermediate filament organization, but not microtubule or microfilament organization. Intermediate filament assembly at the pericortex and secretion were partially restored by 8-bromo-cGMP in LY83583-treated neutrophils, suggesting that cGMP regulates these functions. G-kinase directly induced intermediate filament assembly in situ, and protein phosphatase 1 disassembled filaments. However, in intact cells stimulated with formyl-methionyl-leucyl-phenylalanine, intermediate filament assembly is focal and transient, suggesting that vimentin phosphorylation is compartmentalized. We propose that, in addition to changes in microfilament and microtubule organization, granule secretion is also accompanied by changes in intermediate filament organization, and that cGMP regulates vimentin filament organization via activation of G-kinase.

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