Proper organization of microtubule arrays is essential for intracellular trafficking and cell
motility. It is generally assumed that most if not all microtubules in vertebrate somatic
cells are formed by the centrosome. Here we demonstrate that a large number of
microtubules in untreated human cells originate from the Golgi apparatus in a
centrosome-independent manner. Both centrosomal and Golgi-emanating microtubules
need γ-tubulin for nucleation. Additionally, formation of microtubules at the Golgi
requires CLASPs, microtubule-binding proteins that selectively coat non-centrosomal
microtubule seeds. We show that CLASPs are recruited to trans-Golgi network (TGN) at
the Golgi periphery by the TGN protein GCC185. In sharp contrast to radial centrosomal
arrays, microtubules nucleated at the peripheral Golgi compartment are preferentially
oriented toward the leading edge in motile cells. We propose that Golgi–emanating
microtubules contribute to the asymmetric microtubule networks in polarized cells and
support diverse processes including post-Golgi transport to the cell front
