Both AK1 and AK1B expression inhibits MT nucleation at the GA. (A) Control or flag-AK1–transfected cells incubated on ice for 40 min to depolymerize MTs and rewarmed at the indicated times were triple stained for flag, α-tubulin (αtub), and GMAP210. Single labelings for flag are shown on the left, and the corresponding merged images for α-tubulin and GMAP210 are shown in the middle with enlarged boxes on the right. MT repolymerization in control cells at the same time points (minutes) is shown on the right for comparison. (B) Identical experiments were performed in flag-AK1B–transfected cells, but MTs were depolymerized by NZ treatment. At the indicated times after washout, cells were triple stained for flag, α-tubulin, and GMAP210. NZ recovery in control cells at the same time points is shown on the right for comparison. Bars, 2.5 µm.