So far, so good. An important question remains, however: what role exactly does PP2A-B55 play in
the establishment, execution and maintenance of mitosis? And what is the role of the Greatwall-Ensa
module in these processes? It has been known since 1989 that inhibition of PP2A with okadaic acid
tends to promote premature entry into M-phase (Picard et al.,1989), a finding that has been repeatedly
confirmed over the years.