tailieunhanh - Báo cáo Y học: Binding of gelsolin domain 2 to actin An actin interface distinct from that of gelsolin domain 1 and from ADF/cofilin

UMR 5539 (CNRS) Laboratoire de Motilite Cellulaire (Ecole Pratique des Hautes Etudes), Universite de Montpellier, France; ´ Centre de Recherches de Biochimie Macromoleculaire, Montpellier, France; 3Genes and Development Group, Department of Biomedical Sciences, University of Edinburgh, Scotland It is generally assumed that of the six domains that comprise gelsolin, domain 2 is primarily responsible for the initial contact with the actin filament that will ultimately result in the filament being severed. Other actin-binding regions within domains 1 and 4 are involved in gelsolin’s severing and subsequent capping activity | Eur. J. Biochem. 268 6165-6175 2001 FEBS 2001 Binding of gelsolin domain 2 to actin An actin interface distinct from that of gelsolin domain 1 and from ADF cofilin Celine Renoult1 Laurence Blondin1 Abdellatif Fattoum2 Diane Ternent3 Sutherland K. Maciver3 Fabrice Raynaud1 Yves Benyamin1 and Claude Roustan1 1UMR 5539 CNRS Laboratoire de Motilite Cellulaire Ecole Pratique des Hautes Etudes Universite de Montpellier France 2Centre de Recherches de Biochimie Macromoleculaire Montpellier France 3Genes and Development Group Department of Biomedical Sciences University of Edinburgh Scotland It is generally assumed that of the six domains that comprise gelsolin domain 2 is primarily responsible for the initial contact with the actin filament that will ultimately result in the filament being severed. Other actin-binding regions within domains 1 and 4 are involved in gelsolin s severing and subsequent capping activity. The overall fold of all gelsolin repeated domains are similar to the actin depolymerizing factor ADF cofilin family of actin-binding proteins and it has been proposed that there is a similarity in the actin-binding interface. Gelsolin domains 1 and 4 bind G-actin in a similar manner and compete with each other whereas domain 2 binds F-actin at physiological salt concentrations and does not compete with domain 1. Here we investigate the domain 2 actin interface and compare this to our recent studies of the cofilin actin interface. We conclude that important differences exist between the interfaces of actin with gelsolin domains 1 and 2 and with ADF cofilin. We present a model for F-actin binding of domain 2 with respect to the F-actin severing and capping activity of the whole gelsolin molecule. Keywords actin actin-binding proteins cofilin gelsolin. The organization of the actin microfilaments in cells is dynamic and is quickly rearranged in response to extracellular signals. Gelsolin is one of the members of a family of proteins . severin villin that is .