Supplementary Figure 9: Mechanism of PxL-motif-promoted dephosphorylation.
From: A PxL motif promotes timely cell cycle substrate dephosphorylation by the Cdc14 phosphatase
(a), Depiction of the distances from the C-terminal end of the resolved PxL motif peptide to the MES molecule found in the phosphatase active site in the same (cis) or adjacent (trans) protomer. (b), No evidence for allosteric phosphatase activation by the PxL motif. Velocity of p-NPP hydrolysis by Cdc14 was recorded in the presence of the indicated concentrations of wild-type or scrambled Cbk1-derived PxL motif peptide. The means and s.d. from three independent experiments are shown. (c), Kinetics analysis of peptide dephosphorylation by Cdc14 using an optimal phospho-SPxKK substrate containing an upstream functional or mutant PxL motif. (d), A PxL motif facilitates threonine dephosphorylation by Cdc14. Dephosphorylation velocities were determined using 1 μM Cdc14 and the indicated phosphopeptide concentrations, containing a pTP site preceded by a functional or mutant PxL motif.
