Regulates microtubule organization and stabilization. Promotes microtubule growth and bundling formation and stabilizes microtubules by increasing intense acetylation of microtubules. Both tubulin-binding and homodimer formation are required for NCKAP5L-mediated microtubule bundle formation. Homodimer. Interacts with CDK5RAP2. Interacts with MAPRE1. Interacts with beta-tubulin. Localizes to microtubule plus ends. Associates with centrosomes during interphase, but dissociates from these structures from the onset of mitosis. CDK1/Cyclin B-dependent phosphorylation mediates its dissociation from centrosomes during mitosis.