Criteria used for membrane bud identification in Pf4-Cre:YFP ABM. Plasma membrane buds were identified in high-time-resolution movies using a two-step process: (1) changes to the Mk membrane were initially identified using a surface rendering of YFP and confirmed using z-projection of the raw data; and (2) inspection of each optical section through the entire z-series. (A and B) Plt-like structures at the Mk membrane were classified as buds if they were continuous with the Mk (A); they were classified as passing Plts if no continuity was observed (B). Scale bars, 10 µm. Red arrows in A indicate position of bud; blue arrows in B indicate the position of a passing Plt.