Disease relevance of PTP2

• It was also found that protein tyrosine phosphatases (PTPs) Ptp2 and Ptp3, which inactivate Hog1, have two functions during heat stress [1].

High impact information on PTP2

• Two protein tyrosine phosphatases, Ptp2 and Ptp3, modulate the subcellular localization of the Hog1 MAP kinase in yeast [2].
• In contrast, disruption of PTP3 in combination with its homolog PTP2 results in constitutive tyrosine phosphorylation, enhanced kinase activity of Fus3p MAP kinase on stimulation, and delayed recovery from the cell cycle arrest [3].
• In addition, deletion of PTP2, but not PTP3, exacerbated growth defects due to MKK1-386 [4].
• In vivo and in vitro evidence indicates that both PTPs inactivate Mpk1, but Ptp2 is the more effective negative regulator [4].
• 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 [5].

Biological context of PTP2

• The PTP2 gene is closely linked to the yeast RET1 and STE4 genes and is localized on the right arm of chromosome 15 [6].
• Molecular analysis has shown that PTP1 and PTP2 are quite different structurally and are not especially well conserved at the amino acid sequence level [7].
• 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 [4].

Anatomical context of PTP2

• The ability of PTP2 to complement the cdc25-22 mutant of Schizosaccharomyces pombe was also examined, and unlike the human T-cell PTPase, which was able to complement the cdc25-22 mutant, the S. cerevisiae PTP2 was unable to complement the cdc25-22 mutant of S. pombe [6].
• Differential regulation of the cell wall integrity mitogen-activated protein kinase pathway in budding yeast by the protein tyrosine phosphatases Ptp2 and Ptp3 [4].

Associations of PTP2 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 [8].
• Phosphatase activity is required for suppression since mutation of the catalytic Cys residue in Ptp2 and Ptp3, destroys suppressor function and biochemical activity [8].

Enzymatic interactions of PTP2

• Disruption of PTP2 leads to elevated levels of tyrosine-phosphorylated Hog1p following exposure of cells to high osmolarity [9].

Other interactions of PTP2

• Deletion of PTP2 and PTP3 blocks cells at an early stage of sporulation before premeiotic DNA synthesis and induction of meiotic-specific genes [5].
• We also observed that expression of the PTP2 tyrosine phosphatase gene (a negative regulator of the osmosensing MAP kinase cascade), but not the PTP1 gene (also encoding a tyrosine phosphatase) was induced by nitrogen-starvation [10].
• The S. cerevisiae nitrogen starvation-induced Yvh1p and Ptp2p phosphatases play a role in control of sporulation [10].
• Thus, Ptp2p and Ptp3p are the major phosphatases responsible for the tyrosine dephosphorylation of Hog1p [9].
• Moreover, hyperactivation of Hog1p by deletion of protein phosphatase PTP2 enhanced the response, while blocking the pathway by deletion of the MAPKK PBS2 had a negative effect [11].

References