Direct Demonstration of the Bifunctional Property ofTetrahymena14-nm Filament Protein/Citrate Synthase Following Expression of the Gene inEscherichia coli

1997 ◽  
Vol 237 (2) ◽  
pp. 205-210 ◽  
Author(s):  
Tetsuya Takeda ◽  
Yoshio Watanabe ◽  
Osamu Numata
Keyword(s):  
Citrate Synthase ◽  
Inescherichia Coli ◽  
Direct Demonstration ◽  
Filament Protein

Tetrahymena Intramitochondrial Filamentous Inclusions Contain 14-nm Filament Protein/Citrate Synthase

1995 ◽  
Vol 218 (1) ◽  
pp. 123-131 ◽  
Author(s):  
Osamu Numata ◽  
Tomoyoshi Yasuda ◽  
Yoshio Watanabe
Keyword(s):  
Citrate Synthase ◽  
Filament Protein ◽  
Filamentous Inclusions

scholarly journals The Hsc66-Hsc20 Chaperone System inEscherichia coli: Chaperone Activity and Interactions with the DnaK-DnaJ-GrpE System

1998 ◽  
Vol 180 (24) ◽  
pp. 6617-6624 ◽  
Author(s):  
Jonathan J. Silberg ◽  
Kevin G. Hoff ◽  
Larry E. Vickery
Keyword(s):  
Molecular Chaperone ◽  
Citrate Synthase ◽  
Chaperone Activity ◽  
Inescherichia Coli ◽  
Nucleotide Exchange ◽  
Cellular Functions ◽  
Nucleotide Exchange Factor ◽  
Endogenous Substrates ◽  
Substrate Proteins

ABSTRACT Hsc66, a stress-70 protein, and Hsc20, a J-type accessory protein, comprise a newly described Hsp70-type chaperone system in addition to DnaK-DnaJ-GrpE in Escherichia coli. Because endogenous substrates for the Hsc66-Hsc20 system have not yet been identified, we investigated chaperone-like activities of Hsc66 and Hsc20 by their ability to suppress aggregation of denatured model substrate proteins, such as rhodanese, citrate synthase, and luciferase. Hsc66 suppressed aggregation of rhodanese and citrate synthase, and ATP caused effects consistent with complex destabilization typical of other Hsp70-type chaperones. Differences in the activities of Hsc66 and DnaK, however, suggest that these chaperones have dissimilar substrate specificity profiles. Hsc20, unlike DnaJ, did not exhibit intrinsic chaperone activity and appears to function solely as a regulatory cochaperone protein for Hsc66. Possible interactions between the Hsc66-Hsc20 and DnaK-DnaJ-GrpE chaperone systems were also investigated by measuring the effects of cochaperone proteins on Hsp70 ATPase activities. The nucleotide exchange factor GrpE did not stimulate the ATPase activity of Hsc66 and thus appears to function specifically with DnaK. Cross-stimulation by the cochaperones Hsc20 and DnaJ was observed, but the requirement for supraphysiological concentrations makes it unlikely that these interactions occur significantly in vivo. Together these results suggest that Hsc66-Hsc20 and DnaK-DnaJ-GrpE comprise separate molecular chaperone systems with distinct, nonoverlapping cellular functions.

Immunocytochemical localization of desmin and vimentin in chick embryonic myocardial cells

1990 ◽  
Vol 48 (3) ◽  
pp. 448-449
Author(s):  
Yukiko Sugi
Keyword(s):  
Sodium Methoxide ◽  
Intermediate Filament Protein ◽  
Chick Embryos ◽  
Immunocytochemical Localization ◽  
Myocardial Cells ◽  
Immunofluorescence Study ◽  
Immunofluorescent Localization ◽  
Rabbit Igg ◽  
Semithin Sections ◽  
Filament Protein

In cultured skeletal muscle cells of chick, one intermediate filament protein, vimentin, is primarily formed and then synthesis of desmin follows. Coexistence of vimentin and desmin has been immunocytochemically confirmed in chick embryonic skeletal musclecells. Immunofluorescent localization of vimentin and desmin has been described in developing myocardial cells of hamster. However, initial localization of desmin and vimentin in early embryonic heart has not been reported in detail. By quick-freeze deep-etch method a loose network of intermediate filaments was revealed to exist surrounding myofibrils. In this report, immunocytochemical localization of desmin and vimentin is visualized in early stages of chick embryonic my ocardium.Chick embryos, Hamburger-Hamilton (H-H) stage 8 to hatch, and 1 day old postnatal chicks were used in this study. For immunofluorescence study, each embryo was fixed with 4% paraformaldehyde and embedded in Epon 812. De-epoxinized with sodium methoxide, semithin sections were stained with primary antibodies (rabbit anti-desmin antibody and anti-vimentin antibody)and secondary antibody (RITC conjugated goat-anti rabbit IgG).

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