Human T Cell L-Plastin Bundles Actin Filaments in a Calcium Dependent Manner<sup>1</sup>
Namba, Yuziro; Ito, Masaya; Zu, Youli; Shigesada, Katsuya; Maruyama, Koscak; Namba Yuziro; Department of Cell Biology, Institute for Virus Research, Kyoto University; Ito Masaya; Department of Genetics and Molecular Biology, Institute for Virus Research, Kyoto University; Zu Youli; Department of Cell Biology, Institute for Virus Research, Kyoto University; Shigesada Katsuya; Department of Biology, Faculty of Science, Chiba University; Maruyama Koscak; Department of Genetics and Molecular Biology, Institute for Virus Research, Kyoto University
Журнал:
Journal of Biochemistry
Дата:
1992
Аннотация:
The amino acid sequences deduced from cDNA analyses revealed that human leucocyte L-plastin phosphorylated in response to interleukin 1, 2 closely resembles a chicken intestinal microvilli protein, fimbrin, that bundles actin filaments [de Arruda et al. (1990) J. Cell Biol. 111, 1069–1079]. In the present work, it was observed that unphosphorylated L-plastin isolated from human T cells bundled F-actin just as fimbrin does. L-Plastin acted on T cell β-actin, but hardly acted on muscle γ-actin or chicken gizzard α-actin, whereas fimbrin bundled muscle α-actin. Unlike fimbrin, L-plastin's actin-bundling action was strictly calcium-dependent: the bundles were formed at pCa 7, but not at pCa 6. Under suitable conditions, approximately one molecule of L-plastin bound to 8 molecules of actin monomer in the actin filament.
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