Microtubule plus-end tracking protein that promotes the stabilization of dynamic microtubules. Required for several aspects of mitotic spindle formation including the formation of the overlapping central spindle microtubules and kinetochore attachment. Required for the incorporation of tubulin subunits at the plus ends of kinetochore microtubules during poleward microtubule flux. Acts antagonistically to Klp10A and Klp67A to maintain metaphase spindle length. Also required for guidance of CNS axons downstream of Abl. May function to identify a subset of microtubules that probe the peripheral growth cone domain; where guidance signals exert their influence on cytoskeletal organization. Also required during oogenesis for the organization of the polarized microtubule network inside the 16-cell cyst that ensures oocyte differentiation. {ECO:0000269|PubMed:10747094; ECO:0000269|PubMed:10899121; ECO:0000269|PubMed:12034769; ECO:0000269|PubMed:12538517; ECO:0000269|PubMed:15207236; ECO:0000269|PubMed:15240569; ECO:0000269|PubMed:15592460; ECO:0000269|PubMed:16303556; ECO:0000269|PubMed:16723741}.