Cell Cycle-Dependent Localization of Dynactin Subunit p150^glued at Centrosome

p150^glued is the largest subunit of dynactin protein complex, through which cargo vesicles link to the microtubule minus-end directed motor protein dynein. In addition, p150^glued also locates in the mother centriole where it organizes the subdistal appendage. The components of appendage are dynamically regulated throughout the cell cycle stages, but it is still unclear whether the centrosomal residency of p150^glued correlated with cell cycle progression. Here we found that p150^glued was located in the mother centriole during G1/S stage and its centrosomal residency was independent of microtubule transportation. However, the centrosomal p150^glued became blurred at G2/M phase and this event was not regulated by its phosphorylation. Entering into mitosis, p150^glued was robustly enriched in the mitotic spindle nearby the spindle poles but not in the centrosome. During serum starvation (G0 stage), p150^glued appeared at the base of primary cilium and its depletion attenuated starvation-induced primary cilium formation. We also checked its role in the maintenance of centrosome homeostasis and configuration, and found depletion of p150^glued did not induce centrosome amplification or splitting but inhibited U2OS cell growth. G1 arrest and reduced EdU incorporation were observed in p150^glued deficient U2OS cells. In addition, cyclin E was downregulated following p150^glued depletion. The p53/p21 signaling was activated indicating that CDKs were inactivated. The reduced cell growth was ameliorated in the p150^glued depleted cells when treated with p53 inhibitor. Thus, we have identified the centrosomal targeting of p150^glued in distinct cell cycle stage and uncovered its role in controlling G1/S transition. J. Cell. Biochem. 116: 2049-2060, 2015.