Drosophila katanin is a microtubule depolymerase that regulates cortical-microtubule plus-end interactions and cell migration

Abstract

Regulation of microtubule dynamics at the cell cortex is important for cell motility, morphogenesis and division. Here we show that the Drosophila Katanin, Dm-Kat60, functions to generate a dynamic cortical-microtubule interface in interphase cells. In S2 cells, Dm-Kat60 concentrates at the interphase cell cortex where it suppresses the polymerization of microtubule plus-ends thereby preventing the formation of aberrantly dense cortical arrays. Dm-Kat60 also localizes to the leading edge migratory D17 cells and negatively regulates multiple parameters of their motility. Finally, in vitro, Dm-Kat60 severs and depolymerizes MTs from their ends. Based on these data, we propose that Dm-Kat60 removes tubulin from microtubule ends or lattice that contact specific cortical sites to preventing stable and/or lateral attachments. The asymmetric distribution of such an activity could help generate regional variations in MT behaviors involved in cell migration.

Progressive Transverse Microtubule Array Organization in Hormone-InducedArabidopsisHypocotyl Cells

“…Alternatively, the bias for edge-ward polymerization could be due to cell edge effects (Ambrose et al, 2011;Zhang et al, 2011), such as an upregulation of catastrophe or microtubule severing at the perimeter of these untreated cells (Burk et al, 2001;Wasteneys and Ambrose, 2009;Nakamura et al, 2010). If microtubules underwent a cycle of preferential catastrophe or severing at the edge of the periclinal/anticlinal cell face, followed by a high probability of rescue to polymerization at points within the periclinal array, we would expect to count more apparent plus ends polymerizing toward the cell edge than coming from the cell edge.…”

Microtubule-severing protein Katanin regulates neuromuscular junction development and dendritic elaboration in Drosophila

“…Caenorhabditis elegans mutant for the katanin 60 homolog mei-1 show meiotic spindle abnormalities (Srayko et al, 2006). In Drosophila S2 cells, overexpression of Katanin 60 results in MT severing and depolymerization (Díaz-Valencia et al, 2011;Zhang et al, 2007;Zhang et al, 2011). The susceptibility of MTs to katanin-mediated severing is controlled by many factors; for example, acetylation of MTs sensitizes their severing by katanin (Sudo and Baas, 2010) whereas tau binding to MTs protects them from katanin severing (Qiang et al, 2006;Qiang et al, 2010;Sudo and Baas, 2010;Yu et al, 2008).…”

Microtubule-severing enzymes at the cutting edge

“…1). In other cases, they have more nuanced roles in regulating the behaviors and composition of microtubule ends (Díaz-Valencia et al, 2011;Zhang et al, 2011). This Commentary focuses on our emerging understanding of both the mechanisms of action and cellular functions of this unique group of proteins.…”

“…(D) Drosophila S2 cell migration is mediated by severing enzymes, and katanin has been demonstrated to localize to the leading edge (arrowhead). Reproduced with permission from Zhang, et al 2011. (E) Severing enzymes are found at spindle poles (arrowhead indicates centrosome) and on the chromosomes (arrow) during S2 cell mitosis.…”