Reference: Zheng Y and Jiang Y (2005) The yeast phosphotyrosyl phosphatase activator is part of the Tap42-phosphatase complexes. Mol Biol Cell 16(4):2119-27

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Abstract


Phosphotyrosyl phosphatase activator PTPA is a type 2A phosphatase regulatory protein that possesses an ability to stimulate the phosphotyrosyl phosphatase activity of PP2A in vitro. In yeast Saccharomyces cerevisiae, PTPA is encoded by two related genes, RRD1 and RRD2, whose products are 38 and 37% identical, respectively, to the mammalian PTPA. Inactivation of either gene renders yeast cells rapamycin resistant. In this study, we investigate the mechanism underling rapamycin resistance associated with inactivation of PTPA in yeast. We show that the yeast PTPA is an integral part of the Tap42-phosphatase complexes that act downstream of the Tor proteins, the target of rapamycin. We demonstrate a specific interaction of Rrd1 with the Tap42-Sit4 complex and that of Rrd2 with the Tap42-PP2Ac complex. A small portion of PTPA also is found to be associated with the AC dimeric core of PP2A, but the amount is significantly less than that associated with the Tap42-containing complexes. In addition, our results show that the association of PTPA with Tap42-phosphatase complexes is rapamycin sensitive, and importantly, that rapamycin treatment results in release of the PTPA-phosphatase dimer as a functional phosphatase unit.

Reference Type
Journal Article | Research Support, Non-U.S. Gov't
Authors
Zheng Y, Jiang Y
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Gene Ontology Annotations


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Gene/Complex Qualifier Gene Ontology Term Aspect Annotation Extension Evidence Method Source Assigned On Reference

Interaction Annotations


Genetic Interactions

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

Physical Interactions 14 entries for 6 genes

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InteractorInteractorAssayAnnotationActionModification
PPH21RRD2Affinity Capture-Westernmanually curatedHit-BaitNo Modification
RRD1SIT4Affinity Capture-Westernmanually curatedBait-HitNo Modification
RRD1SIT4Affinity Capture-Westernmanually curatedHit-BaitNo Modification
RRD1PPH21Affinity Capture-Westernmanually curatedBait-HitNo Modification
RRD1TAP42Affinity Capture-Westernmanually curatedBait-HitNo Modification
RRD1TAP42Affinity Capture-Westernmanually curatedHit-BaitNo Modification
SIT4TAP42Affinity Capture-Westernmanually curatedBait-HitNo Modification
SIT4TAP42Affinity Capture-Westernmanually curatedHit-BaitNo Modification
TAP42RRD2Affinity Capture-Westernmanually curatedHit-BaitNo Modification
TAP42RRD2Affinity Capture-Westernmanually curatedBait-HitNo Modification
Showing 1 to 10 of 14 entries