Modifications of Alpha and Beta Carboxy-Terminal Tails Regulate Microtubule Severing by Katanin

Abstract

Microtubules are part of a dynamic cytoskeletal network that is constantly being reorganized to control cell processes such as neuronal development and maintenance, cell division, and cargo transport. Many stabilizing and destabilizing enzymes function to reorganize these networks for the specific needs of the cell in a spatiotemporal manner. Katanin p60 is a microtubule destabilizing enzyme from the ATPases Associated with various Activities (AAA+) family. It recognizes the tubulin carboxy-terminal tails (CTTs) to sever microtubules. Our lab has previously shown free tubulin dimers and CTTs alone can inhibit katanin severing. We seek to determine the manner that tubulin CTTs sequence can regulate katanin activity using polypeptide sequences of CTTs of different tubulin isoforms. We find that the sequence's ionic, hydrophobic, and steric features play a role in determining katanin's activity.