Klar Functions in Nuclear Migration and Droplet Transport
M. A. Welte, S. P. Gross, M. Postner, S. M. Block, E. F. Wieschaus
regulation of vesicle transport in Drosophila embryos: forces and kinetics" Cell
Klar mutations disrupt clouding in the early embryo because lipid droplets fail to move out to the periphery (top panels). Klar mutations also interfere with nuclear migration during eye development (lower panels). In the developing eye disk, the nuclei of the photoreceptor cells are normally positioned apically. In klar mutant animals, these nuclei accumulate on the other, basal side of the tissue.
The role of Klar in eye development appears analogous to its role in droplet transport. Both transport processes reverse net transport with precise timing, and Klar is necessary for the switch from net basal to net apical transport. In both cases, apical transport requires the minus-end motor cytoplasmic dynein. Thus, Klar directly or indirectly regulates this universal eukaryotic motor.