(a-d) Left: fluorescence images of SY5Y cells co-expressing HA-p38 (red) and GFP (green) forms of FL (a) or the indicated truncated Sph1 (b-d). Cells were treated with lactacystin (12 h) and recovered in the presence or absence of serum. Graphs: percentage of p38 existing alone in Agm or co-aggregating with Sph1 in the forms of Agm or Agg (left), and susceptibility of p38 existing on its own in Agm or co-aggregating with Sph1 proteins in Agm toward serum-stimulated autophagic clearance (right). Values are expressed as folds Agm in the presence of serum and are mean+s.e. (n=3). *Significant versus serum+ condition calculated using Student's t-test. 