An antibody-based method for monitoring in vivo oxidation of protein tyrosine phosphatases

Protein tyrosine phosphatases (PTPs) perform specific functions in vivo, despite being vastly outnumbered by their substrates. Because of this and due to the central roles PTPs play in regulating cellular function, PTP activity is regulated by a large variety of molecular mechanisms. We review evidence that indicates that the divergent C-terminal tail sequences (C-terminal domains, CTDs) of receptor-type PTPs (RPTPs) help regulate RPTP function by controlling intermolecular associations in a way that is itself subject to physiological regulation. We propose that the CTD of each RPTP defines an ‘interaction code’ that helps determine molecules it will interact with under various physiological conditions, thus helping to regulate and diversify PTP function.

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Hepatic tyrosine-phosphorylated proteins identified and localized following in vivo inhibition of protein tyrosine phosphatases: effects of H2O2 and vanadate administration into rat livers

Molecular and Cellular Endocrinology ◽

10.1016/0303-7207(93)90206-y ◽

1993 ◽

Vol 97 (1-2) ◽

pp. 9-17 ◽

Cited By ~ 36

Author(s):

Yaron R. Hadari ◽

Benjamin Geiger ◽

Orna Nadiv ◽

Ilana Sabanay ◽

Charles T. Roberts ◽

...

Keyword(s):

Protein Tyrosine Phosphatases ◽

Tyrosine Phosphatases ◽

Protein Tyrosine ◽

Phosphorylated Proteins ◽

Rat Livers

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Essential Functions of Protein Tyrosine Phosphatases Ptp2 and Ptp3 and Rim11 Tyrosine Phosphorylation inSaccharomyces cerevisiaeMeiosis and Sporulation

Molecular Biology of the Cell ◽

10.1091/mbc.11.2.663 ◽

2000 ◽

Vol 11 (2) ◽

pp. 663-676 ◽

Cited By ~ 19

Author(s):

Xiao-Li Zhan ◽

Yulong Hong ◽

Tianqing Zhu ◽

Aaron P. Mitchell ◽

Robert J. Deschenes ◽

...

Keyword(s):

Tyrosine Phosphorylation ◽

Map Kinases ◽

Early Stage ◽

Protein Tyrosine Phosphatases ◽

Homozygous Deletion ◽

Tyrosine Phosphatases ◽

Protein Tyrosine ◽

Biochemical Processes ◽

Tyrosine Phosphorylated Protein

Tyrosine phosphorylation plays a central role in eukaryotic signal transduction. In yeast, MAP kinase pathways are regulated by tyrosine phosphorylation, and it has been speculated that other biochemical processes may also be regulated by tyrosine phosphorylation. Previous genetic and biochemical studies demonstrate that protein tyrosine phosphatases (PTPases) negatively regulate yeast MAP kinases. Here we report that deletion of PTP2 and PTP3results in a sporulation defect, suggesting that tyrosine phosphorylation is involved in regulation of meiosis and sporulation. Deletion of PTP2 and PTP3 blocks cells at an early stage of sporulation before premeiotic DNA synthesis and induction of meiotic-specific genes. We observed that tyrosine phosphorylation of several proteins, including 52-, 43-, and 42-kDa proteins, was changed in ptp2Δptp3Δ homozygous deletion cells under sporulation conditions. The 42-kDa tyrosine-phosphorylated protein was identified as Mck1, which is a member of the GSK3 family of protein kinases and previously known to be phosphorylated on tyrosine. Mutation of MCK1 decreases sporulation efficiency, whereas mutation of RIM11, another GSK3 member, specifically abolishes sporulation; therefore, we investigated regulation of Rim11 by Tyr phosphorylation during sporulation. We demonstrated that Rim11 is phosphorylated on Tyr-199, and the Tyr phosphorylation is essential for its in vivo function, although Rim11 appears not to be directly regulated by Ptp2 and Ptp3. Biochemical characterizations indicate that tyrosine phosphorylation of Rim11 is essential for the activity of Rim11 to phosphorylate substrates. Our data demonstrate important roles of protein tyrosine phosphorylation in meiosis and sporulation

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