ADAM-17 but not caspase-3 cleaves 31 kDa fractalkine. (a) Caspase-3 and (b) α-secretase activities were measured in tissue lysates prepared in phosphate-buffered saline without protease inhibitors using a fluorimetric assay. Bars represent mean, error bars represent standard deviation (n = 5). * P < 0.05. Recombinant mouse caspase-3 (panel a) and a disintegrin and metalloprotease domain (ADAM)-10 or -17 (panel b) were incubated with brain lysate and analysed by Western blotting (n = 4). Numbers represent mass (kDa), as determined using a molecular weight marker.