Figure 5.

α–E-catenin is necessary to couple dynactin-mediated organelle traffic and the actin cytoskeleton. (A–D) Prominent actin cytoskeletons in wild-type (WT; A) and α–E-catenin^−/− (KO; B) keratinocytes and their disruption by latrunculin A treatment (C and D). Immunofluorescence staining with phalloidin. (E and F) Quantitation of lysosome motility in wild-type (E) and α–E-catenin^−/− (F) keratinocytes treated with latrunculin A (+LatruA) or DMSO control. Note that the disruption of the actin cytoskeleton significantly accelerates lysosome motility in wild-type cells (E) but has only a minor impact in α–E-catenin^−/− cells (F). n = 336 for WT + DMSO, n = 337 for WT + LatruA, n = 319 for KO + DMSO, and n = 347 for KO + LatruA. (G) Quantitation of lysosome motility in α–E-catenin^−/− cells expressing the HBT tag, full-length (HBT–α-cat), or VH1–VH2 fragment (HBT–α-cat VH1–2) of α–E-catenin. n = 326 for KO + HBT, n = 323 for KO + HBT–α-cat, and n = 327 for KO + HBT–α-cat VH1–2. Note the decrease in lysosome motility in cells expressing full-length but not truncated α–E-catenin. Quantitation was performed as described in Fig. 4 A. Bar, 23 μm.