Nonreceptor protein tyrosine and lipid Phosphatases in type I Fcε receptor-mediated activation of mast cells and basophils

Protein tyrosine and lipid phosphorylations are early and critical events in type 1 Fcepsilon receptor (FcepsilonRI)-mediated activation of mast cells and basophils. Tyrosine phosphorylation of FcepsilonRI subunits as well as other signal transduction molecules reflects the balance between the action of protein tyrosine kinases and phosphatases. Similarly, the phosphate content of inositol phospholipids, involved in the recruitment of signalling molecules to the plasma membrane and the generation of secondary messengers, is the net result of the opposing effects of phosphoinositide kinases and lipid phosphatases. This review summarizes the current understanding of the structural and functional aspects of nonreceptor protein tyrosine phosphatases (SHP-1, SHP-2, HePTP, PTP20, PRL1, PRL2, PTP-MEG1 and PTP-MEG2) and lipid phosphatases (SHIP and SHIP2) in the activation of mast cells and basophils after FcepsilonRI aggregation. New approaches towards a deeper understanding of the role of phosphatases in mast cell physiology are also discussed. Copyright (C) 2002 S. Karger AG, Basel.