The Ncd tail domain promotes microtubule assembly and stability

Non-claret disjunctional (Ncd) is a Drosophila kinesin-like motor required for spindle assembly and maintenance in oocytes and early embryos. Ncd has an ATP-independent microtubule binding site in the N-terminal tail domain a s well as an ATP-dependent microtubule binding site in the C-terminal motor domain. The Ncd tail domain shares many properties with the microtubule-as sociated proteins that regulate microtubule assembly, including microtubule binding and bundling activity and an abundance of basic and proline residu es. Given these similarities, we examined the ability of Ncd tail domain pr oteins to promote MT assembly and stability. The results indicate that the Ncd tail domain can promote MT assembly and stabilize MTs against condition s that induce MT disassembly, and suggest that Ncd may influence MT dynamic s within the spindle. (C) 1999 Academic Press.