During establishment of epithelial cell polarity, microtubules (MTs) undergo a dramatic reorganization from a radial array to a vertical alignment of non-centrosomal MT bundles that run along the lateral membrane, with their minus ends toward the apical surface and a MT meshwork under the apical and basal membranes. However, the mechanisms underlying MT reorganization are not fully understood. It has been suggested that these MT bundles nucleate from the apical centrosome and are then captured by MT-minus-end-binding proteins, but it is unclear how they are bundled. On page 4671, Atsushi Suzuki and co-workers now present the identification of a new MT-binding protein they call microtubule crosslinking factor 1 (MTCL1). They show here that MTCL1 is a new MT-crosslinker that, although not required for the initial radial growth of MTs from the apical centrosome, is essential for the accumulation of MTs at the lateral cortex of polarising epithelial cells where it promotes the development of lateral MT bundles. Furthermore, the authors demonstrate that MTCL1 is a binding partner of the polarity-regulating kinase PAR-1b, which is known to positively regulate MT dynamics and to have a role in MT reorganization in polarised epithelial cells. On the basis of these results, the authors propose that MTCL1 serves as a scaffold for PAR-1b and recruits the kinase to the lateral MT bundles, which in turn maintains their dynamic state.