Finally, it is highly probable that many mitotic substrates of Cdk1 aretargets for PP2A-B55, since they are poorly phosphorylated in extracts in which Cdk1 activity is high,
but PP2A-B55 cannot be turned off. But in all these cases, direct tests have not been performed, and
comparisons with other forms of PP2A or other protein phosphatases either in the PP2A family or not,
remain to be done.