Vertebrate liver cytokeratins: a comparative study

1987 ◽  
Vol 65 (6) ◽  
pp. 547-557 ◽  
Author(s):  
R. G. Pankov ◽  
A.A. Uschewa ◽  
B. T. Tasheva ◽  
G. G. Markov
Keyword(s):  
Electron Microscopy ◽  
Molecular Weight ◽  
Intermediate Filaments ◽  
Methodological Approach ◽  
Type I ◽  
Type Ii ◽  
Electron Microscopic ◽  
Intermediate Filament Proteins ◽  
Lower Vertebrates ◽  
Microscopic Morphology

The structure and composition of intermediate filaments isolated from liver of representatives of different vertebrate classes have been studied by electron microscopy and biochemical and immunochemical methods. It has been shown that the methodological approach for isolation of rat liver intermediate filaments can be efficiently applied to all other classes of vertebrates. The intermediate filaments studied have the same electron microscopic morphology and are species undistinguishable. The molecular weight of intermediate filament proteins varies from 40 000 to 60 000 and their isoelectric point varies from 5.0 to 6.45. Immunological investigations show that in all animals studied the intermediate filaments are built up of cytokeratins belonging to both types of keratins: type I and type II. Only one protein of the type II cytokeratins is present in all vertebrate classes, whereas in lower vertebrates two or even three type I cytokeratins contribute to the structure of liver intermediate filaments. The biochemical and immunochemical results are discussed with regard to the evolution of liver cytokeratins.

Light and Electron Microscopic Study of Lungs in Bidri Goat and Deccani Sheep

2018 ◽  
Vol 13 (03) ◽  
Author(s):  
S. Ashwini ◽  
A. Ashok Pawar ◽  
K. KB. Sathisha ◽  
M. H. Girish
Keyword(s):  
Electron Microscopy ◽  
Histological Study ◽  
Structural Difference ◽  
Ovis Aries ◽  
Capra Hircus ◽  
Type I ◽  
Type Ii ◽  
Electron Microscopic ◽  
Type Ii Pneumocytes ◽  
Spherical Structures

The histological study of lungs in Bidri goat (Capra hircus) and Deccani sheep (Ovis aries) was carried out to know the structural differences in lungs of these animals. Lungs of both the species had respiratory bronchioles, alveolar duct, alveolar sac and alveoli. Respiratory bronchioles were lined by simple cuboidal epithelium in both the species and more number of respiratory bronchioles was seen in adult Bidri goat than adult Deccani sheep. The alveolar ducts were lined by low cuboidal to simple squamous epithelial cells. Alveoli were spherical structures lined by flat and membranous Type-I pneumocytes and large dome shaped Type-II pneumocytes. In transmission electron microscopy (TEM), more numbers of lamellar bodies were seen in cytoplasm of Type-II pneumocytes of Deccani sheep as compared to Bidri goat. Macrophages and mast cells were noticed in interalveolar septa of both the species. In scanning electron microscopy (SEM), no major structural difference was noticed.

Genes for intermediate filament proteins and the draft sequence of the human genome

2001 ◽  
Vol 114 (14) ◽  
pp. 2569-2575 ◽  
Author(s):  
Michael Hesse ◽  
Thomas M. Magin ◽  
Klaus Weber
Keyword(s):  
Human Genome ◽  
Dna Sequences ◽  
Intermediate Filament ◽  
Muscle Protein ◽  
Gene Families ◽  
Type I ◽  
Type Ii ◽  
Draft Sequence ◽  
Intermediate Filament Proteins ◽  
Processed Pseudogenes

We screened the draft sequence of the human genome for genes that encode intermediate filament (IF) proteins in general, and keratins in particular. The draft covers nearly all previously established IF genes including the recent cDNA and gene additions, such as pancreatic keratin 23, synemin and the novel muscle protein syncoilin. In the draft, seven novel type II keratins were identified, presumably expressed in the hair follicle/epidermal appendages. In summary, 65 IF genes were detected, placing IF among the 100 largest gene families in humans. All functional keratin genes map to the two known keratin clusters on chromosomes 12 (type II plus keratin 18) and 17 (type I), whereas other IF genes are not clustered. Of the 208 keratin-related DNA sequences, only 49 reflect true keratin genes, whereas the majority describe inactive gene fragments and processed pseudogenes. Surprisingly, nearly 90% of these inactive genes relate specifically to the genes of keratins 8 and 18. Other keratin genes, as well as those that encode non-keratin IF proteins, lack either gene fragments/pseudogenes or have only a few derivatives. As parasitic derivatives of mature mRNAs, the processed pseudogenes of keratins 8 and 18 have invaded most chromosomes, often at several positions. We describe the limits of our analysis and discuss the striking unevenness of pseudogene derivation in the IF multigene family. Finally, we propose to extend the nomenclature of Moll and colleagues to any novel keratin.

scholarly journals The Type II Deiodinase Is Retrotranslocated to the Cytoplasm and Proteasomes via p97/Atx3 Complex

2013 ◽  
Vol 27 (12) ◽  
pp. 2105-2115 ◽  
Author(s):  
Rafael Arrojo e Drigo ◽  
Péter Egri ◽  
Sungro Jo ◽  
Balázs Gereben ◽  
Antonio C. Bianco
Keyword(s):  
Molecular Weight ◽  
Endoplasmic Reticulum ◽  
Thyroid Hormone ◽  
High Molecular Weight ◽  
20S Proteasome ◽  
Type I ◽  
Type Ii ◽  
Cell Models ◽  
Natural Substrate ◽  
Iodothyronine Deiodinase

The type II iodothyronine deiodinase (D2) is a type I endoplasmic reticulum (ER)-resident thioredoxin fold-containing selenoprotein that activates thyroid hormone. D2 is inactivated by ER-associated ubiquitination and can be reactivated by two ubiquitin-specific peptidase-class D2-interacting deubiquitinases (DUBs). Here, we used D2-expressing cell models to define that D2 ubiquitination (UbD2) occurs via K48-linked ubiquitin chains and that exposure to its natural substrate, T4, accelerates UbD2 formation and retrotranslocation to the cytoplasm via interaction with the p97-ATPase complex. D2 retrotranslocation also includes deubiquitination by the p97-associated DUB Ataxin-3 (Atx3). Inhibiting Atx3 with eeyarestatin-I did not affect D2:p97 binding but decreased UbD2 retrotranslocation and caused ER accumulation of high-molecular weight UbD2 bands possibly by interfering with the D2-ubiquitin-specific peptidases binding. Once in the cytosol, D2 is delivered to the proteasomes as evidenced by coprecipitation with 19S proteasome subunit S5a and increased colocalization with the 20S proteasome. We conclude that interaction between UbD2 and p97/Atx3 mediates retranslocation of UbD2 to the cytoplasm for terminal degradation in the proteasomes, a pathway that is accelerated by exposure to T4.

scholarly journals The amino acid sequence of component 7c, a type II intermediate-filament protein from wool

1989 ◽  
Vol 261 (3) ◽  
pp. 1015-1022 ◽  
Author(s):  
L G Sparrow ◽  
C P Robinson ◽  
D T W McMahon ◽  
M R Rubira
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Intermediate Filament ◽  
Coiled Coil ◽  
British Library ◽  
Intermediate Filament Protein ◽  
Type I ◽  
Type Ii ◽  
Blocking Group ◽  
Intermediate Filament Proteins

Component 7c is one of the four homologous type II intermediate-filament proteins that, by association with the complementary type I proteins, form the microfibrils or intermediate filaments in wool. Component 7c was isolated as the S-carboxymethyl derivative from Merino wool and its amino acid sequence was determined by manual and automatic sequencing of peptides produced by chemical and enzymic cleavage reactions. It is an N-terminally blocked molecule of 491 residues and Mr (not including the blocking group) of 55,600; the nature of the blocking group has not been determined. The predicted secondary structure shows that component 7c conforms to the now accepted pattern for intermediate-filament proteins in having a central rod-like region of approximately 310 residues of coiled-coil alpha-helix flanked by non-helical N-and C-terminal regions. The central region is divided by three non-coiled-coil linking segments into four helical segments 1A, 1B, 2A and 2B. The N-and C-terminal non-helical segments are 109 and 71 residues respectively and are rich in cysteine. Details of procedures use in determining the sequence of component 7c have been deposited as a Supplementary Publication SUP 50152 (65 pages) at the British Library Document Supply Centre, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1989) 257,5. The information comprises: (1) details of chemical and enzymic methods used for cleavage of component 7c, peptides CN1, CN2 and CN3, and various other peptides, (2) details of the procedures used for the fractionation and purification of peptides from (1), including Figures showing the elution profiles from the chromatographic steps used, (3) details of methods used to determine the C-terminal sequence of peptide CN3, and (4) detailed evidence to justify a number of corrections to the previously published sequence.

scholarly journals A keratin scaffold regulates epidermal barrier formation, mitochondrial lipid composition, and activity

2015 ◽  
Vol 211 (5) ◽  
pp. 1057-1075 ◽  
Author(s):  
Vinod Kumar ◽  
Jamal-Eddine Bouameur ◽  
Janina Bär ◽  
Robert H. Rice ◽  
Hue-Tran Hornig-Do ◽  
...  
Keyword(s):  
Intermediate Filaments ◽  
Lipid Composition ◽  
Comparative Proteomics ◽  
Type I ◽  
Type Ii ◽  
Barrier Formation ◽  
Strong Adhesion ◽  
A Cell ◽  
Mitochondrial Lipid ◽  
Keratin Intermediate Filaments

Keratin intermediate filaments (KIFs) protect the epidermis against mechanical force, support strong adhesion, help barrier formation, and regulate growth. The mechanisms by which type I and II keratins contribute to these functions remain incompletely understood. Here, we report that mice lacking all type I or type II keratins display severe barrier defects and fragile skin, leading to perinatal mortality with full penetrance. Comparative proteomics of cornified envelopes (CEs) from prenatal KtyI−/− and KtyII−/−K8 mice demonstrates that absence of KIF causes dysregulation of many CE constituents, including downregulation of desmoglein 1. Despite persistence of loricrin expression and upregulation of many Nrf2 targets, including CE components Sprr2d and Sprr2h, extensive barrier defects persist, identifying keratins as essential CE scaffolds. Furthermore, we show that KIFs control mitochondrial lipid composition and activity in a cell-intrinsic manner. Therefore, our study explains the complexity of keratinopathies accompanied by barrier disorders by linking keratin scaffolds to mitochondria, adhesion, and CE formation.

scholarly journals Immunogold probes for electron microscopy: evaluation of staining by fluorescence microscopy.

1985 ◽  
Vol 33 (10) ◽  
pp. 995-1000 ◽  
Author(s):  
R B Alexander ◽  
W B Isaacs ◽  
E R Barrack
Keyword(s):  
Electron Microscopy ◽  
Fluorescence Microscopy ◽  
Intermediate Filaments ◽  
Colloidal Gold ◽  
Microscopic Level ◽  
Secondary Antibody ◽  
Light Microscopic Level ◽  
Electron Microscopic ◽  
Cell Monolayers ◽  
Adenocarcinoma Cells

A method is presented whereby the staining of intracellular structures with immunogold probes for electron microscopy can be evaluated at the light microscopic level. Methanol-fixed monolayers of cultured Dunning R-3327-H rat prostatic adenocarcinoma cells were stained for cytokeratins using a two-step immunogold technique consisting of primary anti-keratin antibody followed by gold-labeled secondary antibody. Bound immunogold probe was then visualized with a fluorescent tertiary anti-immunogold probe antibody. Fluorescence microscopy of the whole cell monolayers showed a typical keratin cytoskeleton. The extra staining step did not interfere with subsequent fixation, embedding, and sectioning for electron microscopy, which showed cytoplasmic intermediate filaments decorated with colloidal gold. Using this method, it should be possible to manipulate parameters critical to staining with immunogold probes and to evaluate the labeling without necessitating repeated time-consuming electron microscopic processing. The method also provides a useful correlation between the light microscopic and ultrastructural labeling patterns of immunogold probes.

scholarly journals OBSERVATIONS ON ETCHED ENAMEL IN NON-ERUPTED DECIDUOUS MOLARS: A SCANNING ELECTRON MICROSCOPIC STUDY

1997 ◽  
Vol 11 (3) ◽  
pp. 157-160 ◽  
Author(s):  
Marcelo FAVA ◽  
Ii-Sei WATANABE ◽  
Flávio FAVA DE MORAES ◽  
Luciane RIBEIRO DE REZENDE SUCASAS DA COSTA
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Phosphoric Acid ◽  
Acid Etching ◽  
Etching Time ◽  
Type I ◽  
Type Ii ◽  
Electron Microscopic ◽  
Deciduous Molars ◽  
Scanning Electron

Under the scanning electron microscope, the characteristics of the buccal surface enamel of human non-erupted deciduous molars were evaluated after using 15, 30, and 45 seconds of phosphoric acid etching time. The teeth were extracted, kept in a 70% alcohol solution and later dehydrated and metallized for analysis with the scanning electron microscope JEOL, JSM-6.100. The in vitro experiment with 35% phosphoric acid revealed that there is a tendency of predominance of interprismatic enamel dissolution or type II pattern with 15 and 45 seconds etching time. The dissolution of the interprismatic enamel was more pronounced when an acid etching time of 45 seconds was used. The enamel surface demonstrated type I and type II patterns when acid etching time was 30 seconds

scholarly journals Tailless keratins assemble into regular intermediate filaments in vitro

1990 ◽  
Vol 97 (2) ◽  
pp. 317-324
Author(s):  
M. Hatzfeld ◽  
K. Weber
Keyword(s):  
Intermediate Filaments ◽  
Consensus Sequence ◽  
In Vitro Mutagenesis ◽  
Type I ◽  
Type Ii ◽  
Tail Domain ◽  
Filament Formation ◽  
Wild Type ◽  
Keratin 8

To study the influence of the non alpha-helical tail domain of keratins in filament formation, we prepared a truncated keratin 8 mutant, K8/tailless. Using site-directed in vitro mutagenesis we introduced a stop codon in the position coding for amino acid number 417 of the K8/wild-type sequence, thereby deleting 86 amino acids of the non alpha-helical tail domain but leaving the consensus sequence at the end of the rod domain intact. Expression of the truncated keratin 8 in Escherichia coli allowed us to purify the protein by a two-step procedure. The filament-forming capacity of the truncated K8 with wild-type K18 and K19 was analyzed using in vitro reconstitution. The in vitro assembly studies with K8/tailless and K18 wild-type indicate that the C-terminal tail domain of a type II keratin, including the homologous subdomain H2, is not required for filament formation. Moreover, reconstitution experiments with K8/tailless and K19, a naturally occurring tailless keratin I, show that the tail domains of type I as well as type II keratins are not an essential requirement for in vitro filament formation. Our results suggest that in vitro filament elongation does not depend on interactions between head and tail domains, although the tail domain might have a role in stabilization of intermediate filaments arising from certain keratin pairs.

Structure and synthesis of the peritrophic membrane in Trichoptera larvae

Zoosymposia ◽  
2011 ◽  
Vol 5 (1) ◽  
pp. 63-70
Author(s):  
CARLA CORALLINI
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cardiac Valve ◽  
Food Type ◽  
Peritrophic Membrane ◽  
Type I ◽  
Type Ii ◽  
Food Ingestion ◽  
Transmission Electron ◽  
Anterior Midgut

The peritrophic membrane (PM) in Trichoptera larvae was examined by light, scanning and transmission electron microscopy. The gut of most insects produces 2 fundamental types of PM: Type I is synthesized and secreted by the entire midgut epithelium in response to the ingestion of food; type II is synthesized by specialized cells of the cardiac valve located in the anterior midgut independent from food ingestion. Corallini (2003) described, in the midgut of Limnephilidae larvae, a type I PM which is also secreted by unfed larvae. In this study, both types of PM were observed. Type I PM was evident in larvae of Rhyacophilidae, Leptoceridae, Sericostomatidae and Odontoceridae; the type II PM was observed in larvae of Philopotamidae, Polycentropodidae and Hydropsychidae.

scholarly journals Immunocytochemistry of the pituitary glycoprotein hormones.

1976 ◽  
Vol 24 (7) ◽  
pp. 846-863 ◽  
Author(s):  
G C Moriarty
Keyword(s):  
Secretory Granules ◽  
Thyroid Stimulating Hormone ◽  
Type I ◽  
Glycoprotein Hormones ◽  
Type Ii ◽  
Electron Microscopic ◽  
Tsh Cells ◽  
Immunocytochemical Techniques ◽  
Lh Cells ◽  
Stimulating Hormone

The storage sites of the pituitary glycoprotein hormones were identified with the use of electron microscopic immunocytochemical techniques and antisera to the beta (beta) chains of follicle-stimulating hormone (FSH), luteinizing hormone (LH) and thyroid-stimulating hormone (TSH). The TSH cells in normal rats is ovoid or angular and contains small granules 60-160 nm in diameter. In TSH cells hypertrophied 45 days after thyroidectomy, staining is in globular patches in granules or diffusely distributed in the expanded profiles of dilated rough endoplasmic reticulum. The gonadotrophs (FSH and LH cells) exhibited three different morphologies. Type I cells are ovoid with a population of large granules and a population of small granules. Staining for FSHbeta or LHbeta was intense and specific only in the large granules (diameter of 400 nm or greater). Type II cells are angular or stellate and contain numerous secretory granules averaging 200-220 nm in diameter. They predominate during stages in the estrous cycle when FSH or LH secretion is high. Type III cells look like adrenocorticotropin (ACTH) cells in that they are stellate with peripherally arranged granules. They generally stain only with anti-FSHbeta and their staining can not be abolished by the addition of 100 ng ACTH. In preliminary quantitative studies of cycling females, we found that on serial sections FSH cells and LH cells show similar shifts to a more angular population of cells during stages of active secretion. However, the shifts are not in phase with one another. Furthermore, there are at least 1.5 times more FSH cells than LH cells at all stages of the cycle. Our collection of serial cells shows that some cells (usually type I or II) stain for both gonadotropic hormones, whereas others (usually type II or III) contain only one.

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