Fig. 4

Both phosphorylation and expression pattern of DRP-1 is altered in Aβ accumulating astrocytes. To investigate fission and fusion changes further, the total DRP-1 levels were measured, but there were no changes (A). Depending on where DRP-1 is phosphorylated it can enhance fission (S616) or fusion/fission (S637). However, the protein may also have other functions. Levels of pDRP-1 (S616) were increased in Aβ-exposed astrocytes at day 7 (B), while pDRP-1 (S637) was increased at 7d + 6d after Aβ exposure (C). ICC revealed that the pattern of pDRP-1 (S616) changes dramatically in the presence of Aβ. Aβ-accumulating astrocytes displayed large, concentrated clumps of pDRP-1 (S616), which was not present in control astrocytes (D). Moreover, pDRP-1 (S637) was found to encapsulate BODIPY-positive lipid droplets (E). The separate channels of the merged image (E) are shown in Additional file 4. Scale bar: D = 20 µm; E = 2 µm