Document Detail

Microfilament dynamics during HaCaT cell volume regulation.
MedLine Citation:
PMID:  19036471     Owner:  NLM     Status:  MEDLINE    
Cell volume is an important parameter in many physiological processes, and is closely regulated in many cell types. In those cells, swelling induced by hypotonic media is followed by an ion-driven regulatory volume decrease. In many cell types, this regulatory volume decrease requires an intact actin cytoskeleton. Therefore, we investigated the changes in the structure and polymerization state of the actin cytoskeleton in HaCaT keratinocytes during cell swelling and regulatory volume decrease. Disruption of the actin cytoskeleton by 2microM cytochalasin D inhibits regulatory volume decrease in HaCaT cells. Cells swollen in the presence of low concentrations of cytochalasin D (0.8microM, 305-250mosM) keep the elevated volume even after cytochalasin D removal. A further decrease of tonicity (250-200mosM) is again counteracted by regulatory volume decrease reaching the volume, which has been established at 250mosM. In contrast, no visible changes occurred in actin cytoskeleton morphology of EGFP-actin-transfected HaCaT cells during swelling or regulatory volume decrease. However, biochemical analysis showed an increase in total F-actin levels 90s after the onset of hypotonicity. The ratio of Triton-soluble to -insoluble actin also increased after hypotonic shock, suggesting that the measured increase in F-actin is primarily due to de novo polymerization and formation of short actin filaments, i.e., actin oligomers. These results show that a rapid reorganization of the actin cytoskeleton takes place after hypotonic treatment. This reorganization can influence signaling in response to hypotonicity either indirectly by means of sequestering or releasing actin-associated proteins, or directly by the interaction of short actin filaments with plasma membrane ion channels, and may be involved in determining a new volume set point.
Christopher Blase; Daniel Becker; Sven Kappel; Jürgen Bereiter-Hahn
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-11-25
Journal Detail:
Title:  European journal of cell biology     Volume:  88     ISSN:  1618-1298     ISO Abbreviation:  Eur. J. Cell Biol.     Publication Date:  2009 Mar 
Date Detail:
Created Date:  2009-01-26     Completed Date:  2009-05-18     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7906240     Medline TA:  Eur J Cell Biol     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  131-9     Citation Subset:  IM    
Institute for Cell Biology and Neuroscience, Center of Excellence Frankfurt: Macromolecular Complexes, JW Goethe University, Frankfurt/Main, Germany.
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MeSH Terms
Actins / metabolism
Cell Line
Cell Size* / drug effects
Cytochalasin D / pharmacology
Detergents / pharmacology
Hypotonic Solutions / pharmacology
Keratinocytes / cytology*,  drug effects
Microfilaments / drug effects,  metabolism*
Solubility / drug effects
Reg. No./Substance:
0/Actins; 0/Detergents; 0/Hypotonic Solutions; 22144-77-0/Cytochalasin D

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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