Plus-end tracking protein (+TIP) that binds to the plus-end of microtubules and regulates the dynamics of the microtubule cytoskeleton (PubMed:12388762, PubMed:16109370, PubMed:19632184, PubMed:21646404, PubMed:23001180, PubMed:28726242, PubMed:28814570, PubMed:34608293). Recruits other +TIP proteins to microtubules by binding to a conserved Ser-X-Leu-Pro (SXLP) motif in their polypeptide chains (PubMed:19632184, PubMed:36592928). Promotes cytoplasmic microtubule nucleation and elongation (PubMed:12388762, PubMed:16109370, PubMed:19632184, PubMed:21646404, PubMed:28726242, PubMed:28814570). Involved in mitotic spindle positioning by stabilizing microtubules and promoting dynamic connection between astral microtubules and the cortex during mitotic chromosome segregation (PubMed:12388762, PubMed:34608293). Assists chromosome alignment in metaphase by recruiting the SKA complex to the spindle and stabilizing its interactions with microtubule bundles (K-fibers) (PubMed:27225956, PubMed:36592928). 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 (PubMed:28814570). Promotes elongation of CAMSAP2-decorated microtubule stretches on the minus-end of microtubules (PubMed:28814570). Acts as a regulator of autophagosome transport via interaction with CAMSAP2 (PubMed:28726242). Functions downstream of Rho GTPases and DIAPH1 in stable microtubule formation (By similarity). Promotes microtubule-mediated GJA1/CX43 trafficking to cell membranes via its interaction with DSP, thereby facilitating gap junction intracellular communication (PubMed:25225338). May play a role in cell migration (By similarity). {ECO:0000250|UniProtKB:Q61166, ECO:0000269|PubMed:12388762, ECO:0000269|PubMed:16109370, ECO:0000269|PubMed:19632184, ECO:0000269|PubMed:21646404, ECO:0000269|PubMed:23001180, ECO:0000269|PubMed:25225338, ECO:0000269|PubMed:27225956, ECO:0000269|PubMed:28726242, ECO:0000269|PubMed:28814570, ECO:0000269|PubMed:34608293, ECO:0000269|PubMed:36592928}. This is the function of MAPRE1 (microtubule associated protein RP/EB family member 1, ENSG00000101367).