scholarly journals Cholera toxin can catalyze ADP-ribosylation of cytoskeletal proteins.

1981 ◽  
Vol 91 (2) ◽  
pp. 410-413 ◽  
Author(s):  
H R Kaslow ◽  
V E Groppi ◽  
M E Abood ◽  
H R Bourne

Cholera toxin catalyzes transfer of radiolabel from [32P]NAD+ to several peptides in particulate preparations of human foreskin fibroblasts. Resolution of these peptides by two-dimensional gel electrophoresis allowed identification of two peptides of Mr = 42,000 and 52,000 as peptide subunits of a regulatory component of adenylate cyclase. The radiolabeling of another group of peptides (Mr = 50,000 to 65,000) suggested that cholera toxin could catalyze ADP-ribosylation of cytoskeletal proteins. This suggestion was confirmed by showing that incubation with cholera toxin and [32P]NAD+ caused radiolabeling of purified microtubule and intermediate filament proteins.

1986 ◽  
Vol 240 (2) ◽  
pp. 593-596
Author(s):  
P Strocchi ◽  
J M Gilbert

One of the most abundant acidic proteins in rat brain has an Mr of 68,000 and a pI of 5.6 (68K 5.6 protein) when analysed by two-dimensional gel electrophoresis. The 68K 5.6 protein was found in large relative amounts in brain cytoskeleton preparations and in membrane and supernatant fractions. High-salt washing and proteolytic digestion did not remove this protein from the membrane elements. The 68K 5.6 protein was also found in the microtubule-associated protein fraction of purified microtubules and was present in large relative amounts in preparations of intermediate-filament proteins. The 68K 5.6 protein binds to calmodulin in the presence of Ca2+ ions, and we found it to be an abundant acidic calmodulin-binding protein in brain tissue.


1982 ◽  
Vol 28 (4) ◽  
pp. 955-961 ◽  
Author(s):  
C S Giometti ◽  
K E Willard ◽  
N L Anderson

Abstract Differences in proteins between cells grown as suspension cultures and those grown as attached cultures were studied by comparing the proteins of detergent-resistant cytoskeletons prepared from peripheral blood leukocytes and a lymphoblastoid cell line (GM607) (both grown as suspension cultures) and those of human skin fibroblasts (grown as attached cultures) by two-dimensional gel electrophoresis. The major cytoskeletal proteins of the leukocytes were also present in the protein pattern of GM607 cytoskeletons. In contrast, the fibroblast cytoskeletal protein pattern contained four groups of proteins that differed from the patterns of the leukocytes and GM607. Three groups (Cytoskf:8--10, :14--16, and :17--18) showed qualitative differences, and the fourth group (Cytoskf:11 and :13) showed quantitative differences. In addition, surface labeling of GM607 and human fibroblasts with 125I demonstrated that substantial amounts of vimentin and actin are exposed at the surface of the attached fibroblasts, but there is little evidence of similar exposure at the surface of the suspension-grown GM607. Cytoskf:11 and :13 in fibroblast preparations were also labeled with the 125I. These results demonstrate some differences in cytoskeletal protein composition between different types of cells could be related to their ability or lack of ability to grow as attached cells in tissue culture.


Development ◽  
1986 ◽  
Vol 92 (1) ◽  
pp. 103-113
Author(s):  
Jean Gautier ◽  
Renée Tencer

Patterns of protein phosphorylation and synthesis during axolotl (Ambystoma mexicanum) oocyte maturation were studied by incorporation of [32P]orthophosphate and [35S]methionine into polypeptides, followed by two-dimensional gel electrophoresis. Various alterations were observed after progesterone treatment: de novo appearance of [35S]methionine-labelled polypeptides, a quantitative increase in previously synthesized proteins and a quantitative decrease in or disappearance of other previously synthesized proteins. Changes in 32P- and 35S-labelling were observed very early during maturation. Neither prior oocyte enucleation nor α-amanitin treatment had a significant effect on these changes. Stimulation with MPF provided the same final protein pattern as PG treatment. However, cholera toxin inhibited all the changes seen during maturation. Comparisons between the patterns of [35S]methionine- and [32P]phosphatelabelling provide further information on the biochemical events that take place during oocyte maturation.


1985 ◽  
Vol 54 (03) ◽  
pp. 626-629 ◽  
Author(s):  
M Meyer ◽  
F H Herrmann

SummaryThe platelet proteins of 9 thrombasthenic patients from 7 families were analysed by high resolution two-dimensional gel electrophoresis (HR-2DE) and crossed immunoelectrophoresis (CIE). In 7 patients both glycoproteins (GPs) IIb and Ilia were absent or reduced to roughly the same extent. In two related patients only a trace of GP Ilb-IIIa complex was detected in CIE, but HR-2DE revealed a glycopeptide in the position of GP Ilia in an amount comparable to type II thrombasthenia. This GP Ilia-like component was neither recognized normally by anti-GP Ilb-IIIa antibodies nor labeled by surface iodination. In unreduced-reduced two-dimensional gel electrophoresis two components were observed in the region of GP Ilia. The assumption of a structural variant of GP Ilia in the two related patients is discussed.


2015 ◽  
Vol 22 (12) ◽  
pp. 1066-1075 ◽  
Author(s):  
Adriana Magalhães ◽  
Rayner Queiroz ◽  
Izabela Bastos ◽  
Jaime Santana ◽  
Marcelo Sousa ◽  
...  

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