a map6-related protein is present in protozoa and is involved in flagellum motilitymap6-related蛋白存在于原生动物,参与鞭毛的能动性.pdfVIP

A MAP6-Related Protein Is Present in Protozoa and Is Involved in Flagellum Motility Denis Dacheux1,2,3, Nicolas Landrein1,2, Magali Thonnus1,2, Guillaume Gilbert1,2¤, Annelise Sahin1,2, 1,2 1,2 ´ 1,2 Harald Wodrich , Derrick R. Robinson , Melanie Bonhivers * ´ ´ ´ ´ ´ 1 Microbiologie Fondamentale et Pathogenicite, Universite de Bordeaux, UMR 5234, Bordeaux, France, 2 Microbiologie Fondamentale et Pathogenicite, CNRS, UMR 5234, ´ ´ Bordeaux, France, 3 Microbiologie Fondamentale et Pathogenicite, Institut Polytechnique de Bordeaux, UMR 5234, Bordeaux, France Abstract In vertebrates the microtubule-associated proteins MAP6 and MAP6d1 stabilize cold-resistant microtubules. Cilia and flagella have cold-stable microtubules but MAP6 proteins have not been identified in these organelles. Here, we describe TbSAXO as the first MAP6-related protein to be identified in a protozoan, Trypanosoma brucei. Using a heterologous expression system, we show that TbSAXO is a microtubule stabilizing protein. Furthermore we identify the domains of the protein responsible for microtubule binding and stabilizing and show that they share homologies with the microtubule- stabilizing Mn domains of the MAP6 proteins. We demonstrate, in the flagellated parasite, that TbSAXO is an axonemal protein that plays a role in flagellum motility. Lastly we provide evidence that TbSAXO belongs to a group of MAP6-related proteins (SAXO proteins) present only in ciliated or flagellated organisms ranging from protozoa to mamm