Cytoplasmic dynein is a molecular motor responsible for various cellular activities, including intracellular transport and cell division. To achieve various functions, dynein needs to be regulated by other proteins, and it has still been elusive how these regulations are achieved in many cellular contexts.
Using the early embryos of Caenorhabditis elegans, we focused on the spatiotemporal regulation of dynein during mitosis, where dynein and its regulatory proteins translocated from the cytoplasm to the spindle region, and observed the dynamics of dynein and the regulatory proteins.
We revealed that there are i) selectivity, ii) varieties in the accumulation sites, and iii) the order of accumulation in the accumulation dynamics in the spindle region.
Furthermore, we found that the accumulation of NUD-2 was unique among the dynein regulators we analyzed. NUD-2 started to accumulate before NEBD (pre-NEBD accumulation). Using a protein injection approach, we revealed that the C-terminal helix of NUD-2 was responsible for pre-NEBD accumulation. These findings suggest a fine temporal control of the subcellular localization of regulatory proteins.
This work was supported by JSPS Grants-in-Aid for Scientific Research JP19K16094, JP18H02414, JP18H05529, and JP18KK0202.
Figure: (a) The future spindle region (purple) is compartmentalized by nuclear membrane before cell division. In mitosis, nuclear envelope breakdown (NEBD) allows proteins to translocate between the cytoplasm and the spindle region. Dynein and its related proteins (green) mainly exist in the cytoplasm before NEBD and enter the spindle region upon NEBD. (b) The graph shows the temporal patterns of protein accumulations in the spindle region. The mean intensity of proteins in the spindle region is normalized by the mean intensity of cytoplasmic proteins. The plots show that the accumulation does not occur simultaneously, but sequentially.
