A pool of flagellar surface proteins on the plasma membrane can supply regenerating flagella.

<p>Cells were biotinylated and flagella were isolated from the freshly biotinylated cells (1^st). Cells regenerated flagella, deflagellated (R1), and regenerated flagella a second time (R2). A: Flagellar lengths before the first deflagellation (1^st), first (R1) and second (R2) regeneration. B–D: Membrane+Matrix stained with CB or blotted and stained with AP-streptavidin (Biotin). Density of selected bands stained with CB (1C–6C) or AP-streptavidin (6B–13B) presented as a percentage of the density of the bands in flagella isolated immediately after biotinylation (1^st). Coomassie blue stained proteins in each fraction were nearly identical (B) but the quantity of biotinylated protein decreased with each regeneration (C), indicating that the pool of biotinylated protein was gradually depleted as flagella grew.