Biochemical evidence for interaction between smoothelin and filamentous actin

Article Article scientifique Article Biochemical evidence for interaction between smoothelin and filamentous actin eng 2004 author Niessen Petra author Clement Sophie 759123 author Fontao Lionel 514347 author Chaponnier Christine 25579 author Teunissen Birgit 133495 author Rensen Sander author Van Eys Guillaume author Gabbiani Giulio 24889 170-178 10.1016/j.yexcr.2003.09.005 14720516 0014-4827 http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6WFC-49W6NNN-4-C&_cdi=6791&_user=779890&_pii=S0014482703004920&_orig=search&_coverDate=01%2F01%2F2004&_sk=997079998&view=c&wchp=dGLbVtz-zSkWb&md5=07fb72a337cab46a80411d98ab6890e5&ie=/sdarticle.pdf The two major isoforms of smoothelin (A and B) contain a calponin homology (CH) domain, colocalize with alpha-smooth muscle actin (alpha-SMA) in stress fibers and are only expressed in contractile smooth muscle cells (SMCs). Based on these findings, we hypothesized that smoothelins are involved in smooth muscle cell contraction, presumably via interaction with actin. The interaction between smoothelins and three different actin isoforms (alpha- and gamma-smooth muscle and alpha-skeletal actin [alpha-SKA]) was investigated using several in vitro assays. Smoothelin-B co-immunoprecipitated with alpha-smooth muscle actin from pig aorta extracts. In rat embryonic fibroblasts, transfected smoothelins-A and -B associated with stress fibers. In vitro dot blot assays, in which immobilized actin was overlaid with radio-labeled smoothelin, showed binding of smoothelin-A to actin filaments, but not to monomeric G-actin. A truncated smoothelin, containing the calponin homology domain, associated with stress fibers when transfected and bound to actin filaments in overlay, but to a lesser extent. ELISA results showed that the binding of smoothelin to actin has no significant isoform specificity. Our results indicate an interaction between smoothelin and actin filaments. Moreover, the calponin homology domain and its surrounding sequences appear to be sufficient to accomplish this interaction, although the presence of other domains is apparently necessary to facilitate and/or strengthen the binding to actin. Actins/ metabolism Animals Aorta/chemistry Calcium-Binding Proteins/metabolism Cell Line Cytoskeletal Proteins/chemistry/genetics/ metabolism Enzyme-Linked Immunosorbent Assay Escherichia coli/genetics Fibroblasts/cytology/ metabolism Glutathione Transferase/metabolism Microfilament Proteins Muscle Proteins Precipitin Tests Protein Isoforms/chemistry/genetics/ metabolism Protein Structure, Tertiary Rats/ embryology Recombinant Fusion Proteins/metabolism Stress Fibers/metabolism Swine Transfection Dewey 616.07 137 Département de pathologie et immunologie 21F false Experimental cell research 292 1 6b3298e4-7bc9-42c9-968b-f6070dc70705 Article Restricted file1.pdf 535102 application/pdf restrictedAccess Faculté de médecine / Section de médecine fondamentale / Département de pathologie et immunologie

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Biochemical evidence for interaction between smoothelin and filamentous actin	Experimental cell research			2004	656	0

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Teunissen, Birgit