Protein Tyrosine Phosphatase PTP1 Negatively Regulates Dictyostelium STATa and Is Required for Proper Cell-Type Proportioning

Developmental Biology

Eugene Kim¹  Jeffrey G. Williams¹  John Moniakis¹  Richard A. Firtel¹  Marianne Gamper¹  Tony Hunter¹  Anne Early¹ 

[1] MRC Laboratory for Molecular Cell Biology, Department of Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom

关键词: cell-type differentiation;    Dictyostelium discoideum;    protein tyrosine phosphatases;    signaling pathways;    STAT;   

DOI  :  10.1006/dbio.2001.0171

学科分类：生物科学（综合）

来源: Academic Press

【 摘 要 】

TheproteintyrosinephosphatasePTP1,whichmediatesreversiblephosphorylationontyrosine,hasbeenshowntoplayanimportantregulatoryroleduringDictyosteliumdevelopment.MutantslackingPTP1developmorerapidlythannormal,whilestrainsthatoverexpressPTP1displayaberrantmorphology.However,thesignallingpathwaysinvolvedhavenotbeencharacterised.Inreexaminingthesestrains,wehavefoundthatthereisaninversecorrelationbetweenlevelsofPTP1activity,theextentoftyrosinephosphorylationonDictyosteliumSTATaaftertreatmentwithcAMP,andtheproportionoftheslugpopulationexhibitingSTATanuclearenrichmentinvivo.ThissuggeststhatPTP1actstoattenuatethetyrosinephosphorylationofSTATaanddownstreamSTATa-mediatedpathways.Consistentwiththis,weshowthatwhenPTP1isoverexpressed,thereisincreasedexpressionofaprestalkcellmarkerattheslugposterior,aphenocopyofSTATanullslugs.Inptp1nullstrains,STATatyrosinephosphorylationandnuclearenrichmentinthesluganteriorisincreased.Thereisalsoachangeintheprestalktopresporecellratio.Synergyexperimentssuggestthatthisisduetoacell-autonomousdefectinformingthesubsetofpresporecellsthatarelocatedintheanteriorpresporeregion.

【 授权许可】

Unknown