Figure 1.

Involvement of TEMs and TRAP-enriched domains in FcεRI signalosome. At the level of the plasma membrane, there is a cross-talk of FcεRI, consisting of four transmembrane subunits (α,β, and γγ), with tetraspanins and TRAPs. These interactions affect FcεRI signal transduction. Phosphorylated ITAMs of FcεRI bind LYN kinase, which is connected to the membrane by palmitoylation and myristoylation. Two important TRAPs, NTAL and LAT, which occupy different nanodomains, are also palmitoylated. Tetraspanins are represented by CD9, which contains six palmitoylation domains and one possible glycosylation site in a small intracellular loop, two disulfide bonds and tetraspanin conserved motif CCG are also depicted in the figure. Finally, integrins are represented by palmitoylated α4β1 that is located in close proximity of CD9. The membrane is connected with the actin cytoskeleton through the FERM (4.1,ezrin/radixin/moesin) domain and actin-binding domain (Abd) of ERM proteins. FERM binds directly to phosphatidylinositol 4 5-bisphosphate (PIP2).