Mikrodomeny błony komórkowej miejscem zapoczątkowania szlaków sygnałowych przez immunoreceptory

Abstrakt

Summary Sphingolipids and cholesterol of the plasma membrane self-organize into microdomains named rafts. They are 30-50 nm dynamic lipid assemblies that facilitate local accumulation of GPI-anchored proteins and Src family protein tyrosine kinases in their outer and inner leaflet, respectively. It has been demonstrated in the last five years that immunoreceptors, including TCR, BCR and Fc receptors, associate with rafts upon binding of their polyvalent ligands. Within rafts, tyrosine residues of the receptor signaling sequence ITAM are phosphorylated by kinases of the Src family, being convert simultaneously into docking sites for Syk and Zap70 tyrosine kinases. The joint activity of the Src and Syk/Zap70 families of tyrosine kinases triggers signaling cascades leading eventually to proper responses of cells. An important feature of this process is a fusion of rafts of various composition bringing together molecules required for formation of signaling complexes at activated immunoreceptors.