Microtubules (MTs) are dynamic cytoskeleton polymers forming a polarized intracellular network that provides structural support, facilitates intracellular transport and drives chromosome segregation. To investigate how microtubules control cell dynamics with high spatial and temporal accuracy, we developed a photo-inactivated variant of the key MT plus-end adaptor EB1, that allows local and acute manipulation of MT growth dynamics by controlling the recruitment of EB-dependent plus end tracking proteins (+TIPs) to MT ends. Blue light-induced rapid and reversible dissociation of the +TIP complex from MTs results in a MT growth rate decrease and induces depolymerization of cell edge associated MTs (van Haren et al. 2018, Nat. Cell Biol. 20, 252–261). I will discuss our development and validation of this optogenetic tool and results supporting independent roles of +TIP complexes and the canonical MT polymerase XMAP215/CKAP5 in promoting physiological MT growth rates in cells, as well as ongoing work investigating the consequences of local modulation of MT growth on neuron morphogenesis.