Fig. 5. Distribution of GFP-tagged myosin 5 in cdk5^ts mutants. (A) In the control strain FB1, a biologically active GFPMyo5 fusion protein localizes to the growing tip of the bud and the distal cell pole, in which it is thought to prepare the next bud site. Bar, 3 µm. (B) In budding cdk5^ts mutant cells at the permissive temperature, GFP-Myo5 is also concentrated at the growing cell poles (arrows). In addition, GFP-Myo5 is found at septa that are, in contrast to control cells, often found in the middle of the mother cell. The polar localization of GFP-Myo5 remains constant over time (compare T=0s and T=16s). Bar, 3 µm. (C) At restrictive temperature (34°C, 4-5 hours), some cdk5^ts cells still contain a polar cluster of GFP-Myo5 (arrow at T=0s and box). However, cells only transiently accumulate GFP-Myo5 at the cell pole (arrow in T=16s). In cases where the GFP-Myo5 spot remains at one cell pole, it rapidly rearranges at the putative growth region (arrowheads in detail). Bar, 3 µm. (D) Time series of cell poles of cdk5^ts cells show that the GFP-Myo5 accumulation at the growth region remains stationary at the permissive temperature (left series, 22°C), but undergoes rapid rearrangement at restrictive temperature (arrow in right series, 34°C). Elapsed time is given in seconds:milliseconds. Bar, 2 µm.