The C-terminal region of Hok1 targets to endosomes. (A) The organization of human Hook3, Hok1, and the truncated proteins Hok11–224, Hok1225–624, and Hok1625–930. (B) Morphology of Δhok1 expressing Hok11–224, Hok1225–624, and Hok1625–930. (C) Colocalization of Hok11–224, Hok1225–624, Hok1625–930, and Hok11–624 and mCherry-Rab5a–labeled EEs in Δhok1. The cell edge is indicated in blue. Only the C-terminal fragment of Hok1 localizes to apical EE clusters. (D) Organization of Hok11–624 and Hok11–624PX. The latter carries an EE-targeting PX domain (Wedlich-Söldner et al., 2000). (E) Morphology of control cells and Δhok1 that express Hok1, Hok11–624, and Hok11–624PX. Targeting of truncated Hok1 to EEs partially rescues the growth defect. (F) Bidirectional motility of mCherry-Rab5a–labeled EEs and Hok11–624PX. The upper two kymographs are contrast inverted. Hok11–624PX locates on the moving organelles (yellow lines in merged image). See also Video 3. Images in B, C, E, and F were adjusted in brightness, contrast, and γ settings. Horizontal bars are in micrometers, and the vertical bar is in seconds.
