A Novel Microtubule-Depolymerizing Kinesin Involved in Length Control of a Eukaryotic Flagellum

Christine Blaineau (1) , Magali Tessier (1) , Pascal Dubessay (2) , Lena Tasse (3) , Lucien Crobu (4) , Michel Pagès (4) , Patrick Bastien (5)

1 FRE3013 - Biologie moléculaire, biologie cellulaire et biodivesité des protozoaires parasites
2 RGM - Réparation du Génome Mitochondrial Normal et Pathologique
3 LISBP - Laboratoire d'Ingénierie des Systèmes Biologiques et des Procédés
4 MIVEGEC - Maladies infectieuses et vecteurs : écologie, génétique, évolution et contrôle
5 MIVEGEC-BioGEPPE - Biologie, Génétique et Pathologie des Pathogènes Eucaryotes

Cilia and flagella are complex, microtubule (MT)-filled cell organelles of which the structure is evolutionarily conserved from protistan cells to mammalian sperm and the size is regulated. The best-established model for flagellar length (FL) control is set by the balance of continuous MT assembly and disassembly occurring at the flagellar tip. Because steady-state assembly of tubulin onto the distal end of the flagellum requires intraflagellar transport (IFT)—a bidirectional movement of large protein complexes that occurs within the flagellum—FL control must rely upon the regulation of IFT. This does not preclude that other pathways might ‘‘directly’’ affect MT assembly and disassembly. Now, among the super family of kinesins, family-13 (MCAK/KIF2) members exhibit a MT-depolymerizing activity responsible for their essential functions in mitosis. Here we present a novel family-13 kinesin from the flagellated protozoan parasite Leishmania major, that localizes essentially to the flagellum, and whose over expression produces flagellar shortening and knockdown yields long flagella. Using negative mutants, we demonstrate that this phenotype is linked with the MT-binding and depolymerizing activity of this kinesin. This is the first report of an effector protein involved in FL control through a direct action in MT dynamics, thus this finding complements the assembly–disassembly model.

Keywords: Flagella; Depolymerizing; kinesins; Protein

Domains: Life Sciences [q-bio]; Life Sciences [q-bio]; Microbiology and Parasitology; Parasitology; Life Sciences [q-bio]; Cellular Biology; Subcellular Processes [q-bio.SC]

Christine Blaineau, Magali Tessier, Pascal Dubessay, Lena Tasse, Lucien Crobu, et al.. A Novel Microtubule-Depolymerizing Kinesin Involved in Length Control of a Eukaryotic Flagellum. Current Biology - CB, 2007, 17 (9), pp.778-782. ⟨10.1016/j.cub.2007.03.048⟩. ⟨hal-02049647⟩