caa a22 4500 397557329 CHVBK 20180308164806.0 cr unu---uuuuu 161202e199604 xx s 000 0 eng 10.1093/oxfordjournals.jbchem.a021309 doi (NATIONALLICENCE)oxford-10.1093/oxfordjournals.jbchem.a021309 F-Actin Bundling Activity of Tetrahymena Elongation Factor lα Is Regulated by Ca2+/Calmodulin [Elektronische Daten] [Yasuhiro Kurasawa, Kazuko Hanyu, Yoshio Watanabe, Osamu Numata] Translation elongation factor la (EF-la) catalyzes the GTP-dependent binding of amino-acyl-tRNA to the ribosome.Previously, Tetrahymena 14-nm filament-associated protein was identified as EF-la [Kurasawa et aL (1992) Exp. Cell Res; 203, 261-268]. This and several other studies suggest that EF-la functions not only in translation but also in regulation of some part of the cytoskeleton. Tetrahymena EF-lα bound to F-actin and induced bundling of F-actin. We investigated the effects of GTP/GDP and Ca2+calmodulin on F-actin bundling activity of EF-lα. The presence of GTP, GDP, or guanylyl-imidodi-phosphate (GMP-PNP) slightly decreased the amount of EF-lαbound to F-actin, but each had virtually no effect on the F-actin bundling activity. The formation of F-actin bundles by EF-lα was Ca2+-insensitive. In the absence of Ca2+, calmodulin did not bind to EF-lα and F-actin. On the other hand, in the presence of Ca2+, calmodulin directly bound to EF-lα but did not have any serious influence on EF-lα/F-actin binding. Under the conditions, electron microscopy demonstrated that Ca2+/calmodulin completely inhibited the F-actin bundling by EF-lα. These results indicate that Ca2+/calmodulin regulates the F-actin bundling activity of EF-lα without inhibition of the binding between EF-lα and F-actin. © by the Journal of Biochemistry Regular Papers nationallicence calmodulin nationallicence cytoskeletal regulation nationallicence elongation factor la nationallicence F-actin bundling nationallicence Tetrahymena nationallicence Kurasawa Yasuhiro Institute of Biological Sciences, University of Tsukuba Tsukuba, Ibaraki 305 aut Hanyu Kazuko Institute of Biological Sciences, University of Tsukuba Tsukuba, Ibaraki 305 aut Watanabe Yoshio Joubu University Isesaki, Gumma 372 aut Numata Osamu Institute of Biological Sciences, University of Tsukuba Tsukuba, Ibaraki 305 aut The Journal of Biochemistry Oxford University Press 119/4(1996-04), 791-798 0021-924X 119:4<791 1996 119 jbchem https://doi.org/10.1093/oxfordjournals.jbchem.a021309 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1093/oxfordjournals.jbchem.a021309 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kurasawa Yasuhiro Institute of Biological Sciences, University of Tsukuba Tsukuba, Ibaraki 305 aut NATIONALLICENCE 700 1- Hanyu Kazuko Institute of Biological Sciences, University of Tsukuba Tsukuba, Ibaraki 305 aut NATIONALLICENCE 700 1- Watanabe Yoshio Joubu University Isesaki, Gumma 372 aut NATIONALLICENCE 700 1- Numata Osamu Institute of Biological Sciences, University of Tsukuba Tsukuba, Ibaraki 305 aut NATIONALLICENCE 773 0- The Journal of Biochemistry Oxford University Press 119/4(1996-04), 791-798 0021-924X 119:4<791 1996 119 jbchem Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford