The Tec family protein-tyrosine kinases: a subset of kinases for a subset of signalings

Abstract

The Tec family has emerged recently as a subfamily among nonreceptor type protein-tyrosine kinases, consisting of Tec, Btk, Itk/Tsk/Emt, Bmx, and Txk/Rlk. Because many members of this family have been shown to be activated in response to growth and differentiation stimuli in hematopoietic tissues, they are presumed to function in vivo as important signaling mediators. Although that hypothesis was further strengthened by the knowledge that mutations in Btk cause agammaglobulinemia in humans, we have only limited information concerning the molecular interaction through which Tec kinases exert their effects. One characteristic feature of Tec family members is the presence of a pleckstrin homology domain in their protein structure, suggesting a physical and functional interaction with the phospholipid-dependent signaling pathways. Recent data have revealed that Tec kinases regulate phospholipase C isoforms. This review summarizes current knowledge concerning the in vivo roles of the Tec family proteins.