Microtubule plus-end tracking protein that promotes the stabilization of dynamic microtubules. Involved in the nucleation of noncentrosomal microtubules originating from the trans-Golgi network (TGN). Required for the polarization of the cytoplasmic microtubule arrays in migrating cells towards the leading edge of the cell. May act at the cell cortex to enhance the frequency of rescue of depolymerizing microtubules. This cortical microtubule stabilizing activity is regulated at least in part by phosphatidylinositol 3-kinase signaling. Also performs a similar stabilizing function at the kinetochore which is essential for the bipolar alignment of chromosomes on the mitotic spindle. Interacts with microtubules. Localizes to microtubule plus ends. The two SXIP sequence motifs are important for targeting to the growing microtubule plus ends. Two TOG regions display structural characteristics similar to HEAT repeat domains and mediate interaction with microtubules. Belongs to the CLASP family.