The Pyst2-L phosphatase is involved in cell-crowding

Orlev Levy-Nissenbaum*, Shlomit Ben-Menachem, Orit Sagi-Assif, Isaac P. Witz

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


The dual-specificity phosphatase Pyst2-L was found to be over expressed in leukocytes derived from AML and ALL patients as well as in certain other solid tumors and lymphoblastoid cell lines. Pyst2-L, binds and dephosphorylates both pERKs and pJNKs proteins, and thus, plays a role in regulating the MAP kinase signaling pathway. In the present study, a comparative genomic application was used and sequence analysis of multi-organisms databases were searched in order to identify genes homologous to Pyst2-L. The Xenopus laevis MAP kinase phosphatase X17c gene and the Yeast nitrogen starvation-induced protein phosphatase Yvh1p gene were revealed to be highly homologous with Pyst2-L. Both X17c and Yvh1p genes play a role in cell cycle regulation. A down regulated expression of the Yvh1p gene occurred in Saccharomyces cerevisiae that were synchronized to the G2-phase of the cell cycle by α-factor. In conformity with this result, a reduction in Pyst2-L expression levels was observed in G2-phase-synchronized Human K562 cells. Finally, we were able to show that cells in highly crowded cultures express high levels of the Pyst2-L phosphatase. These observations may indicate that low levels of the Pyst2-L phosphatase are essential for the G2-phase of the cell cycle and that this phosphatase might play a role in signaling cascades induced by cellular crowding.

Original languageEnglish
Pages (from-to)138-145
Number of pages8
JournalImmunology Letters
Issue number1-2
StatePublished - 15 Apr 2006


FundersFunder number
Arnold and Ruth Feuerstein
Fainbarg Family Fund
Jacqueline Seroussi Memorial Foundation for Cancer Research
Israel Cancer Research Fund


    • Dual-specificity phosphatases
    • Pyst2
    • Pyst2-L
    • X17c
    • Yvh1p


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