Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt
Combined Automated Annotation using Multiple IEA Methods
Regulation of Dictyostelium protein-tyrosine phosphatase-3 (PTP3) through osmotic shock and stress stimulation and identification of pp130 as a PTP3 substrate.
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Stress induces Ser/Thr phosphorylation of PTP3 and its translocation from the cytosol to endosome-like vesicles; a C-to-S trap mutant binds pp130 (later identified as STATc).
"Mutation of the catalytically essential Cys to a Ser results in inactive PTP3 that forms a stable complex with tyrosine-phosphorylated p130 (pp130) in vivo and in vitro"
OSBPa, a predicted oxysterol binding protein of Dictyostelium, is required for regulated entry into culmination.
Evidence that DIF-1 and hyper-osmotic stress activate a Dictyostelium STAT by inhibiting a specific protein tyrosine phosphatase.
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PTP3 directly binds and dephosphorylates STATc; DIF-1 and hyperosmotic stress inhibit PTP3, activating STATc.
"We show that PTP3 directly interacts with and dephosphorylates STATc"
A Dictyostelium homologue of the metazoan Cbl proteins regulates STAT signalling.
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CblA positively regulates STATc tyrosine phosphorylation by downregulating PTP3.
"as a positive regulator of STATc tyrosine phosphorylation, by downregulating PTP3"
Dual regulation of a Dictyostelium STAT by cGMP and Ca2+ signalling.
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Osmotic stress and Ca2+-elevating agents induce phosphorylation of PTP3 on S448 and S747, which inhibits PTP3 toward STATc.
"We show that two serine residues in PTP3, S448 and S747, are rapidly phosphorylated after osmotic stress."
Perturbations of the actin cytoskeleton activate a Dictyostelium STAT signalling pathway.
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DIF-1 and actin depolymerising drugs increase PTP3 S747 phosphorylation and activate STATc.
"There are two sites of serine phosphorylation on PTP3, S448 and S747, and modification at these sites correlates with a reduction in phosphatase activity."
Identification of the kinase that activates a nonmetazoan STAT gives insights into the evolution of phosphotyrosine-SH2 domain signaling.
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Pyk2 is the constitutive STATc Tyr922 kinase that PTP3 counterbalances.
"predicted constitutive STATc tyrosine kinase activity is counterbalanced in vivo by the DIF-1-regulated activity of PTP3, a Tyr922 phosphatase"
Identification of the protein kinases Pyk3 and Phg2 as regulators of the STATc-mediated response to hyperosmolarity.
Two Dictyostelium tyrosine kinase-like kinases function in parallel, stress-induced STAT activation pathways.
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PTP3 co-immunoprecipitates with the STATc kinase Pyk2 and co-localises with it in stress-induced granules.
"Biochemical coimmunoprecipitation analysis confirms that there is a Pyk2 and PTP3 interaction and that it increases after sorbitol treatment"
Multiple roles of the novel protein tyrosine phosphatase PTP3 during Dictyostelium growth and development.
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Recombinant PTP3 is a vanadate-sensitive phosphatase; the gene is present in two copies and complete disruption could not be obtained.
"We were unable to obtain a strain with disruptions in both PTP3 genes."