Plus-end tracking protein (+TIP) that binds to the plus-end of microtubules and regulates the dynamics of the microtubule cytoskeleton. Recruits other +TIP proteins to microtubules by binding to a conserved Ser-X-Leu-Pro (SXLP) motif in their polypeptide chains. Promotes cytoplasmic microtubule nucleation and elongation. Involved in mitotic spindle positioning by stabilizing microtubules and promoting dynamic connection between astral microtubules and the cortex during mitotic chromosome segregation. Assists chromosome alignment in metaphase by recruiting the SKA complex to the spindle and stabilizing its interactions with microtubule bundles (K-fibers). Also acts as a regulator of minus-end microtubule organization: interacts with the complex formed by AKAP9 and PDE4DIP, leading to recruit CAMSAP2 to the Golgi apparatus, thereby tethering non-centrosomal minus-end microtubules to the Golgi, an important step for polarized cell movement. Promotes elongation of CAMSAP2-decorated microtubule stretches on the minus-end of microtubules. Acts as a regulator of autophagosome transport via interaction with CAMSAP2. Functions downstream of Rho GTPases and DIAPH1 in stable microtubule formation. May play a role in cell migration 