Rabbit Anti-Human PPP2CA (Phospho-Tyr307) polyclonal antibody

Spindle positioning and spindle elongation are critical for proper cell division. In human cells, an evolutionary conserved ternary complex (NuMA/LGN/Gai) anchors dynein at the cortex during metaphase, thus ensuring correct spindle positioning. Whether this complex contributes to anaphase spindle elongation is not known. More generally, the mechanisms coupling mitotic progression with spindle behaviour remain elusive. Here, we uncover that levels of cortical dynein markedly increase during anaphase in a NuMA-dependent manner. We demonstrate that during metaphase, CDK1-mediated phosphorylation at T2055 negatively regulates NuMA cortical localization and that this phosphorylation is counteracted by PPP2CA phosphatase activity. We establish that this tug of war is essential for proper levels of cortical dynein and thus spindle positioning during metaphase. Moreover, we find that upon CDK1 inactivation in anaphase, the rise in dephosphorylated NuMA at the cell cortex leads to cortical dynein enrichment, and thus to robust spindle elongation. Our findings uncover a mechanism whereby the status of NuMA phosphorylation coordinates mitotic progression with proper spindle function.

The protein phosphatase type 2A alpha throughout the dephosphorylation of serine/threonine residues of phosphoproteins is involved in numerous cellular functions, including cell division. Using the fluorescence in situ hybridization method, the gene encoding catalytic subunit-of PP2A alpha (locus symbol Ppp2ca) was assigned to rat chromosome 10 at a band of q22. The present study provides new evidence for the conserved syntenic association between human chromosome 5q23-q31 and the rat chromosome 10q22.