title: The Pyst2-L phosphatase is involved in cell-crowding.
abstract: 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 alpha-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.
authors.affiliation: Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, 69978 Tel Aviv, Israel. orle@post.tau.ac.il
authors.forename: Orlev
authors.initials: O
authors.lastname: Levy-Nissenbaum
authors.forename: Shlomit
authors.initials: S
authors.lastname: Ben-Menachem
authors.forename: Orit
authors.initials: O
authors.lastname: Sagi-Assif
authors.forename: Isaac P
authors.initials: IP
authors.lastname: Witz
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002453:Cell Cycle / Q000235:genetics; D002478:Cells, Cultured; D054642:Dual Specificity Phosphatase 6; D054637:Dual-Specificity Phosphatases; D005786:Gene Expression Regulation; D006801:Humans; D008969:Molecular Sequence Data; D010749:Phosphoprotein Phosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017027:Protein Tyrosine Phosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; D029867:Xenopus Proteins; D010749:Phosphoprotein Phosphatases; C510445:DUSP6 protein, Xenopus; C107523:DUSP7 protein, human; D054642:Dual Specificity Phosphatase 6; D054637:Dual-Specificity Phosphatases; D017027:Protein Tyrosine Phosphatases; C121559:YVH1 protein, S cerevisiae