Microtubule release from the centrosome

摘要: Although microtubules (MTs) are generally thought to originate at the centrosome, a number of cell types have significant populations MTs with no apparent centrosomal connection. The origin these noncentrosomal has been unclear. We applied kinetic analysis MT formation in vivo establish their mode origin. Time-lapse fluorescence microscopy demonstrated that cultured epithelial cells arise primarily by constitutive nucleation at, and release from, centrosome. After release, moved away from centrosome tended depolymerize. Laser-marking experiments released individually plus ends leading, suggesting they were transported minus end-directed motors. Released dynamic. laser marking grew, paused, or shortened while stable shortened. Microtubule may serve two kinds cellular function. Release transport could generate arrays observed cells, neurons, other asymmetric, differentiated cells. would also contribute polymer turnover exposing ends, thereby providing additional sites for loss subunits. population reflect steady-state nucleation, dynamics.