Binds to the plus end of microtubules and regulates the dynamics of the microtubule cytoskeleton. May be involved in anchoring microtubules to their nucleation sites and/or functioning as a reservoir for distribution to the growing end. In plants, microtubule minus ends are not necessarily severed from the nucleation site and transported to the plus end of a microtubule as part of the recycling process. May play a role in endomembrane organization during polarized growth of plant cells. Interacts with the tobamovirus movement protein (MP) and may play a role in the association of MP with the microtubule system during infection. Homodimer and heterodimer with EB1B. Interacts with tobamovirus movement protein. Localizes both to the plus ends of microtubules and to the sites of nucleation during division and interphase. Highly expressed in guard cells of leaf stomata, pollen grains and pollen tubes. Expressed in young roots. Composed of two functionally independent domains. The N-terminal domain forms a hydrophobic cleft involved in microtubule binding and the C-terminal is involved in protein binding. In Arabidopsis thaliana, EB1A and EB1B possess an acidic C-terminal tail that has autoinhibitory function, but EB1C has a tail region with patches of basic amino acid residues required for nuclear targeting. No visible phenotype under normal growth conditions. Plant microtubules behave differently from those of other eukaryotes in mitosis: they lack centrosomes and spindles are barrel-shaped with unfocused poles and no astral microtubules. Belongs to the MAPRE family.