Figure 4.

SKIP Contains a KLC2 Binding Motif and Is Required for Acidification-Induced Movement of Lysosomes

(A and B) Schematic of human SKIP showing the region encoded by exon 7 which is skipped in some mRNAs, and an alignment with the same region of SKIP orthologs from other vertebrates (Xl, Xenopus laevis, Dr, Danio rerio, Tn, Tetraodon nigroviridis). The regions similar to the kinesin-binding WD motif are highlighted in red, with the motif shown underneath (Morgan et al., 2010).

(C) Confocal micrographs showing the distribution of lysosomes in cells expressing the two splice variants of SKIP. The variant lacking exon 7 does not induce a peripheral accumulation of lysosomes.

(D) Confocal micrographs of HeLa cells stained for the lysosomal marker CD63 with, or without, treatment with acetate Ringer's solution pH 6.5 for 30 min to acidify the cytosol. Lysosomal movement to the periphery was reduced by RNAi of Arl8b or SKIP.

(E and F) Quantitation of siRNA-treated cells on a micropatterned array as in Figure 2F shows reduced peripheral movement even after prolonged acetate treatment (60 min) See also Figure S4.