Arabidopsis katanin binds microtubules using a multimeric microtubule-binding domain.
Katanin is a heterodimeric protein that mediates ATP-dependent destabilization of microtubules in animal cells. In plants, the catalytic subunit of Arabidopsis thaliana katanin (AtKSS, Arabidopsis thaliana Katanin Small Subunit) has been identified and its microtubule-severing activity has been demonstrated in vitro. In vivo, plant katanin plays a role in the organization of cortical microtubules, but the way it achieves this function is unknown. To go further in our understanding of the mechanisms by which katanin severs microtubules, we analyzed the functional domains of Arabidopsis katanin. We characterized the microtubule-binding domain of katanin both in vitro and in vivo. It corresponds to a poorly conserved sequence between plant and animal katanins that is located in the N-terminus of the protein. This domain interacts with cortical microtubules in vivo and has a low affinity for microtubules in vitro. We also observed that katanin microtubule-binding domain oligomerizes into trimers. These results show that, besides being involved in the interaction of katanin with microtubules, the microtubule-binding domain may also participate in the oligomerization of katanin. At the structural level, we observed that AtKSS forms ring-shaped oligomers.
Stoppin-Mellet
Virginie
V
Laboratoire de Physiologie Cellulaire Végétale, UMR 5168, CNRS/CEA/INRA/Université Joseph Fourier, Institut de Recherches en Sciences et Technologies pour le Vivant, 17 rue des Martyrs, Grenoble Cedex 9, France.
Gaillard
Jérémie
J
Timmers
Ton
T
Neumann
Emmanuelle
E
Conway
James
J
Vantard
Marylin
M
D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D006801:Humans; D000074201:Katanin; D008870:Microtubules / Q000378:metabolism*; D008969:Molecular Sequence Data; D030821:Plants, Genetically Modified; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D029681:Arabidopsis Proteins; D017931:DNA Primers; D018744:DNA, Plant; D011993:Recombinant Fusion Proteins; D000251:Adenosine Triphosphatases; C436244:KTN1 protein, Arabidopsis; D000074201:Katanin