Fig. 3. Cell spreading is altered by HDAC6 level. (A) Early events in spreading of HDAC6 WT and HDAC6 KO MEFs, measured using computer-assisted TIRF microscopy to track the boundaries of the cell during spreading on fibronectin-coated coverslips. Top two panels show quantification of spread cell areas at each time interval. Bottom panel shows quantification of the percentage of membrane protrusions (red) and retractions (blue) in the two cell types, calculated as active length along the periphery vs total length along the periphery. The percentage of edge activity (protrusion in red, retraction in blue) was determined at each time by the quotient (active length of the cell periphery) ÷ (total length of the periphery). The warmth of color (green to blue; yellow to red) indicates greater velocity of retractions and protrusions, respectively. Note that the time course selected by the automated analysis software is slightly different for the two cell types in the lower graphs. (B) Long-term spreading of HDAC6 WT and HDAC6 KO MEFs that had been allowed to spread on uncoated-glass coverslips was quantified from the surface area drawn to include all adhesions.