X Zhang, Q Chen, J Feng, J Hou, F Yang, J Liu, Q Jiang and C. Zhang
Journal of Cell Science, 2009, 122(13), 2240-2251. DOI: 10.1242/jcs.042747
Nedd1 is a new member of the -tubulin ring complex (TuRC) and targets the TuRC to the centrosomes for microtubule nucleation and spindle assembly in mitosis. Although its role is known, its functional regulation mechanism remains unclear. Here we report that the function of Nedd1 is regulated by Cdk1 and Plk1. During mitosis, Nedd1 is firstly phosphorylated at T550 by Cdk1, which creates a binding site for the polo-box domain of Plk1. Then, Nedd1 is further phosphorylated by Plk1 at four sites: T382, S397, S637 and S426. The sequential phosphorylation of Nedd1 by Cdk1 and Plk1 promotes its interaction with -tubulin for targeting the TuRC to the centrosome and is important for spindle formation. Knockdown of Plk1 by RNAi decreases Nedd1 phosphorylation and attenuates Nedd1 accumulation at the spindle pole and subsequent -tubulin recruitment at the spindle pole for microtubule nucleation. Taken together, we propose that the sequential phosphorylation...