Reference: Van Hoof C, et al. (2005) Specific interactions of PP2A and PP2A-like phosphatases with the yeast PTPA homologues, Ypa1 and Ypa2. Biochem J 386(Pt 1):93-102

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Abstract


To elucidate the specific biological role of the yeast homologues of PTPA (phosphatase 2A phosphatase activator), Ypa1 and Ypa2 (where Ypa stands for yeast phosphatase activator), in the regulation of PP2A (protein phosphatase 2A), we investigated the physical interaction of both Ypa proteins with the catalytic subunit of the different yeast PP2A-like phosphatases. Ypa1 interacts specifically with Pph3, Sit4 and Ppg1, whereas Ypa2 binds to Pph21 and Pph22. The Ypa1 and Ypa2 proteins do not compete with Tap42 (PP2A associating protein) for binding to PP2A family members. The interaction of the Ypa proteins with the catalytic subunit of PP2A-like phosphatases is direct and independent of other regulatory subunits, implicating a specific function for the different PP2A-Ypa complexes. Strikingly, the interaction of Ypa2 with yeast PP2A is promoted by the presence of Ypa1, suggesting a positive role of Ypa1 in the regulation of PP2A association with other interacting proteins. As in the mammalian system, all yeast PP2A-like enzymes associate as an inactive complex with Yme (yeast methyl esterase). Ypa1 as well as Ypa2 can reactivate all these inactive complexes, except Pph22-Yme. Ypa1 is the most potent activator of PP2A activity, suggesting that there is no direct correlation between activation potential and binding capacity.

Reference Type
Comparative Study | Journal Article | Research Support, Non-U.S. Gov't
Authors
Van Hoof C, Martens E, Longin S, Jordens J, Stevens I, Janssens V, Goris J
Primary Lit For
RRD1 | RRD2
Additional Lit For
PPH22 | PPH3 | PPE1 | PPH21 | SIT4 | PPG1 | TAP42 | TAP42-RRD2-PPH21 phosphatase complex | TAP42-RRD2-PPH22 phosphatase complex | TAP42-RRD1-SIT4 phosphatase complex

Interaction Annotations


Genetic Interactions

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Interactor Interactor Allele Assay Annotation Action Phenotype SGA score P-value Source Reference

Physical Interactions 10 entries for 7 genes

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InteractorInteractorAssayAnnotationActionModification
PPH21RRD2Reconstituted Complexmanually curatedHit-BaitNo Modification
PPH21TAP42Reconstituted Complexmanually curatedHit-BaitNo Modification
PPH22RRD2Reconstituted Complexmanually curatedHit-BaitNo Modification
PPH22TAP42Reconstituted Complexmanually curatedHit-BaitNo Modification
PPH3TAP42Reconstituted Complexmanually curatedHit-BaitNo Modification
RRD1PPH3Reconstituted Complexmanually curatedBait-HitNo Modification
RRD1SIT4Reconstituted Complexmanually curatedBait-HitNo Modification
RRD1SIT4Affinity Capture-Westernmanually curatedHit-BaitNo Modification
SIT4RRD2Affinity Capture-Westernmanually curatedBait-HitNo Modification
SIT4TAP42Reconstituted Complexmanually curatedHit-BaitNo Modification
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