Microtubule-binding protein which stabilizes dynamic microtubules by slowing growth and shrinkage at both plus and minus ends and serves as a sensor of microtubule damage (By similarity). Induces microtubule branching which is mediated by the formation of long SSNA1 fibrils which guide microtubule protofilaments to split apart from the mother microtubule and form daughter microtubules (PubMed:30250060). Required for cell division (PubMed:12640030). Self-assembles into fibrils in a head-to-tail fashion. During cell division, levels are elevated between hours 0 at the onset of division and 4 at mid-divison. After 5 hours, when division is close to completion, levels decrease and stay low until hour 7. RNAi-mediated knockdown results in multinucleate, multiflagellate cells. Belongs to the SSNA1 family.