CDC-48/p97 is required for proper meiotic chromosome segregation via controlling AIR-2/Aurora B kinase localization in Caenorhabditis elegans

CDC-48/p97 is a AAA (ATPases associated with diverse cellular activities) chaperone involved in protein conformational changes such as the disassembly of protein complexes. We previously reported that Caenorhabditis elegans CDC-48.1 and CDC-48.2 (CDC-48s) are essential for the progression of meiosis I metaphase. Here, we report that CDC-48s are required for proper chromosome segregation during meiosis in C. elegans. In wild-type worms, at the diakinesis phase, phosphorylation of histone H3, one of the known substrates of aurora B kinase (AIR-2), on meiosis I chromatids correlated with AIR-2 localization at the cohesion sites of homologous chromatids. Conversely, depletion of CDC-48s resulted in a significant expansion of signals for AIR-2 and phosphorylated histone H3 over the entire length of meiotic chromosomes, leading to defective chromosome segregation, while the total amount of AIR-2 in lysates was not changed by the depletion of CDC-48s. The defective segregation of meiotic chromosomes caused by the depletion of CDC-48s was suppressed by the simultaneous depletion of AIR-2 and is similar to that observed following the depletion of protein phosphatase 1 (PP1) phosphatases. However, the amount and localization of PP1 were not changed by the depletion of CDC-48s. These results suggest that CDC-48s control the restricted localization of AIR-2 to the cohesion sites of homologous chromatids in meiosis I.