High impact information on PTP3

• We have isolated a novel protein tyrosine phosphatase gene, PTP3, as a negative regulator of this pathway [1].
• Ptp3p directly dephosphorylates and inactivates Fus3p MAP kinase in vitro [1].
• In addition, deletion of PTP2, but not PTP3, exacerbated growth defects due to MKK1-386 [2].
• Ptp2 was more efficient than Ptp3 at binding and dephosphorylating Mpk1 [2].
• Regulation of the Saccharomyces cerevisiae HOG1 mitogen-activated protein kinase by the PTP2 and PTP3 protein tyrosine phosphatases [3].

Biological context of PTP3

• Here we report that deletion of PTP2 and PTP3 results in a sporulation defect, suggesting that tyrosine phosphorylation is involved in regulation of meiosis and sporulation [4].
• To further examine the functions and substrate specificities of Ptp2 and Ptp3, we tested whether they could inactivate a third MAPK, Mpk1, in the cell wall integrity pathway [2].

Anatomical context of PTP3

• Differential regulation of the cell wall integrity mitogen-activated protein kinase pathway in budding yeast by the protein tyrosine phosphatases Ptp2 and Ptp3 [2].

Associations of PTP3 with chemical compounds

• Two genes encoding protein-tyrosine phosphatases, PTP2, and a new phosphatase, PTP3, have been isolated in a genetic selection for negative regulators of an osmotic stress response pathway called HOG, for high osmolarity glycerol, in budding yeast [5].
• Phosphatase activity is required for suppression since mutation of the catalytic Cys residue in Ptp2 and Ptp3, destroys suppressor function and biochemical activity [5].

Physical interactions of PTP3

• Catalytically inactive Ptp2 and Ptp3 coprecipitate with Hog1 from yeast extracts [5].

Regulatory relationships of PTP3

• Thus Ptp2 and Ptp3 likely act in a negative feedback loop to inactivate Hog1 [5].

Other interactions of PTP3

• Deletion of PTP2 and PTP3 blocks cells at an early stage of sporulation before premeiotic DNA synthesis and induction of meiotic-specific genes [4].
• Ptp2 is predominantly nuclear whereas Ptp3 is cytoplasmic, suggesting that active Mpk1 is present in the nucleus [2].

Analytical, diagnostic and therapeutic context of PTP3

• Northern blot analyses suggest that Hog1p regulates Ptp2p and/or Ptp3p activity at the posttranscriptional level [3].

References