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pubmed-2114670
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oai_dc
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pubmed-21146702008-05-01 Cytoskeletal reorganization of human platelets after stimulation revealed by the quick-freeze deep-etch technique Articles We studied the cytoskeletal reorganization of saponized human platelets after stimulation by using the quick-freeze deep-etch technique, and examined the localization of myosin in thrombin-treated platelets by immunocytochemistry at the electron microscopic level. In unstimulated saponized platelets we observed cross-bridges between: adjoining microtubules, adjoining actin filaments, microtubules and actin filaments, and actin filaments and plasma membranes. After activation with 1 U/ml thrombin for 3 min, massive arrays of actin filaments with mixed polarity were found in the cytoplasm. Two types of cross-bridges between actin filaments were observed: short cross-bridges (11 +/- 2 nm), just like those observed in the resting platelets, and longer ones (22 +/- 3 nm). Actin filaments were linked with the plasma membrane via fine short filaments and sometimes ended on the membrane. Actin filaments and microtubules frequently ran close to the membrane organelles. We also found that actin filaments were associated by end- on attachments with some organelles. Decoration with subfragment 1 of myosin revealed that all the actin filaments associated end-on with the membrane pointed away in their polarity. Immunocytochemical study revealed that myosin was present in the saponin-extracted cytoskeleton after activation and that myosin was localized on the filamentous network. The results suggest that myosin forms a gel with actin filaments in activated platelets. Close associations between actin filaments and organelles in activated platelets suggests that contraction of this actomyosin gel could bring about the observed centralization of organelles. The Rockefeller University Press 1987-10-01 /pmc/articles/PMC2114670/ /pubmed/3667697 Text en This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).
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| repository_type |
Open Access Journal
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| institution_category |
Foreign Institution
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| institution |
US National Center for Biotechnology Information
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| building |
NCBI PubMed
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| collection |
Online Access
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| language |
English
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| format |
Online
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| title |
Cytoskeletal reorganization of human platelets after stimulation revealed by the quick-freeze deep-etch technique
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| spellingShingle |
Cytoskeletal reorganization of human platelets after stimulation revealed by the quick-freeze deep-etch technique
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| title_short |
Cytoskeletal reorganization of human platelets after stimulation revealed by the quick-freeze deep-etch technique
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| title_full |
Cytoskeletal reorganization of human platelets after stimulation revealed by the quick-freeze deep-etch technique
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| title_fullStr |
Cytoskeletal reorganization of human platelets after stimulation revealed by the quick-freeze deep-etch technique
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| title_full_unstemmed |
Cytoskeletal reorganization of human platelets after stimulation revealed by the quick-freeze deep-etch technique
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| title_sort |
cytoskeletal reorganization of human platelets after stimulation revealed by the quick-freeze deep-etch technique
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| description |
We studied the cytoskeletal reorganization of saponized human platelets after stimulation by using the quick-freeze deep-etch technique, and examined the localization of myosin in thrombin-treated platelets by immunocytochemistry at the electron microscopic level. In unstimulated saponized platelets we observed cross-bridges between: adjoining microtubules, adjoining actin filaments, microtubules and actin filaments, and actin filaments and plasma membranes. After activation with 1 U/ml thrombin for 3 min, massive arrays of actin filaments with mixed polarity were found in the cytoplasm. Two types of cross-bridges between actin filaments were observed: short cross-bridges (11 +/- 2 nm), just like those observed in the resting platelets, and longer ones (22 +/- 3 nm). Actin filaments were linked with the plasma membrane via fine short filaments and sometimes ended on the membrane. Actin filaments and microtubules frequently ran close to the membrane organelles. We also found that actin filaments were associated by end- on attachments with some organelles. Decoration with subfragment 1 of myosin revealed that all the actin filaments associated end-on with the membrane pointed away in their polarity. Immunocytochemical study revealed that myosin was present in the saponin-extracted cytoskeleton after activation and that myosin was localized on the filamentous network. The results suggest that myosin forms a gel with actin filaments in activated platelets. Close associations between actin filaments and organelles in activated platelets suggests that contraction of this actomyosin gel could bring about the observed centralization of organelles.
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| publisher |
The Rockefeller University Press
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| publishDate |
1987
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| url |
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2114670/
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| _version_ |
1611413362253496320
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