Fig. 3.

ST protein is a specific inhibitor of PP2A. (A,A′) Inhibition of APC/C activity by ST protein, as measured by Cyclin B Y170A destruction, can be competed out by co-injection with a 1.5 to 2-fold excess of ascidian PP2A A subunit protein over ST protein (n in parentheses; error bars represent s.e.m.). (B,B′) APC/C activity, again measured by Cyclin B Y170A destruction, is unperturbed when STR7A is injected instead of ST (n in parentheses, error bars represent s.e.m.). All graphs shown are example traces.