Fig. 3. Changes in the levels of podosome-associated actin and paxillin during cluster-ring transition. RAW cells expressing GFP-actin or YFP-paxillin were induced to differentiate into osteoclasts, and recorded at 15-second intervals by time-lapse video microscopy. Frames are presented in an intensity spectrum scale. A negative time point indicates seconds before the transition. Time point 0 indicates the beginning of cluster-ring transition. (A) An increase in GFP-actin intensity (about tenfold) is evident during cluster-ring transition (0-105"). (B) A slight decrease in YFP-paxillin intensity is noted during cluster-ring transition (0-105"). Arrows indicate the ring. Bars, 10 µm.