title: Glutamylated tubulin: diversity of expression and distribution of isoforms.
abstract: Glutamylation of alpha and beta tubulin isotypes is a major posttranslational modification giving rise to diversified isoforms occurring mainly in neurotubules, centrioles, and axonemes. Monoglutamylated tubulin isoforms can be differentially recognized by two mAbs, B3 and GT335, which both recognize either polyglutamylated isoforms. In the present study, immunoelectron microscopy and immunofluorescence analyses were performed with these two mAbs to determine the expression and distribution of glutamylated tubulin isoforms in selected biological models whose tubulin isotypes are characterized. In mouse spermatozoa, microtubules of the flagellum contain polyglutamylated isoforms except in the tip where only monoglutamylated isoforms are detected. In spermatids, only a subset of manchette microtubules contain monoglutamylated tubulin isoforms. Cytoplasmic microtubules of Sertoli cells are monoglutamylated. Mitotic and meiotic spindles of germ cells are monoglutamylated whereas the HeLa cell mitotic spindle is polyglutamylated. Three models of axonemes are demonstrated as a function of the degree and extent of tubulin glutamylation. In lung ciliated cells, axonemes are uniformly polyglutamylated. In sea urchin sperm and Chlamydomonas, flagellar microtubules are polyglutamylated in their proximal part and monoglutamylated in their distal part. In Paramecium, cilia are bi- or monoglutamylated only at their base. In all cells, centrioles or basal bodies are polyglutamylated. These new data emphasize the importance of glutamylation in all types of microtubules and strengthen the hypothesis of its role in the regulation of the intracellular traffic and flagellar motility.
authors.affiliation: Laboratoire de Biologie Cellulaire, EA 2508 MENRT, Université Paris V, UFR Biomedicale, 45 rue des Saintes-Pères, 75270 Paris cedex 06, France. Marie-Louise.Kann@biomedicale.univ-paris5.fr
authors.forename: Marie-Louise
authors.initials: ML
authors.lastname: Kann
authors.forename: Sylvie
authors.initials: S
authors.lastname: Soues
authors.forename: Nicolette
authors.initials: N
authors.lastname: Levilliers
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Fouquet
mesh_terms: D000818:Animals; D002696:Chlamydomonas; D056890:Eukaryota / Q000378:metabolism* / Q000648:ultrastructure; D005407:Flagella / Q000378:metabolism / Q000648:ultrastructure; D018698:Glutamic Acid / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008854:Microscopy, Electron; D008870:Microtubules / Q000378:metabolism* / Q000648:ultrastructure; D008954:Models, Biological; D010247:Paramecium; D020033:Protein Isoforms / Q000378:metabolism; D011499:Protein Processing, Post-Translational / Q000502:physiology; D011817:Rabbits; D051381:Rats; D017208:Rats, Wistar; D020545:Respiratory Mucosa / Q000378:metabolism* / Q000648:ultrastructure; D013094:Spermatozoa / Q000378:metabolism* / Q000648:ultrastructure; D014404:Tubulin / Q000378:metabolism*
chemical_list: D020033:Protein Isoforms; D014404:Tubulin; D018698:Glutamic Acid