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Interaction of AU‐rich sequence binding proteins with actin: Possible involvement of the actin cytoskeleton in lymphokine mRNA turnover
Author(s) -
Henics Tamás,
Nagy Eszter,
SzekeresBarthó Júlia
Publication year - 1997
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/(sici)1097-4652(199710)173:1<19::aid-jcp3>3.0.co;2-m
Subject(s) - cytochalasin , microfilament , biology , cytoskeleton , actin , microbiology and biotechnology , cytochalasin b , actin binding protein , polysome , cytochalasin d , lymphokine , messenger rna , cytoplasm , actin cytoskeleton , rna , in vitro , biochemistry , cell , gene , ribosome
In the current study, we report that cytochalasin‐induced disruption of microfilaments stabilizes lymphokine mRNAs in activated human peripheral blood lymphocytes. Parallel with this, a dose‐ and time‐dependent increase in AU‐rich sequence binding protein (AUPB) activities is apparent in the nonionic detergent‐resistant fractions of these cells, suggesting that cytochalasin‐induced modulation of lymphokine mRNA stability might be mediated through cytoplasmic AUBPs. We provide evidence that some of the AUBPs can be immunoprecipitated with anti‐actin antibodies, implicating the potential of these proteins to associate with the actin‐based cytoskeleton in vivo. Moreover, disruption of the microfilament network by cytochalasins produces increased immunoprecipitable actin‐AUBP complexes in the detergent‐resistant cytoplasmic subfractions of lymphocytes. We show that cytochalasin‐induced changes in AUBP activities are parallel with their higher binding affinity to RNA containing AU‐rich instability sequence element as judged by in vitro competition and in vivo ultraviolet‐crosslinking analysis. Correlation of these findings with changes in mRNA stability indicates that the actin cytoskeleton may play a physiologically important role in posttranscriptional regulation of lymphokine gene expression during early lymphocyte activation. J. Cell. Physiol. 173:19–27, 1997. © 1997 Wiley‐Liss, Inc.