Immunoreceptor tyrosine-based activation motif

The motif contains a tyrosine separated from a leucine or isoleucine by any two other amino acids, giving the signature YxxL/I. == Function ==

and ζ-chain accessory molecules. ITAMs are represented in blue on the tails of the CD3 subunits. ITAMs are important for signal transduction, mainly in immune cells. They are found in the cytoplasmic tails of non-catalytic tyrosine-phosphorylated receptors such as the CD3 and ζ-chains of the T cell receptor complex, the CD79-alpha and -beta chains of the B cell receptor complex, and certain Fc receptors. Exact mechanisms of this phenomenon are as of yet not elucidated. Other non-catalytic tyrosine-phosphorylated receptors carry a conserved inhibitory motif (ITIM) that, when phosphorylated, results in the inhibition of the signaling pathway via recruitment of phosphatases, namely SHP-1, SHP-2 and SHIP1. This serves not only for inhibition and regulation of signalling pathways related to ITAM-based signalling, but also for termination of signalling. == Genetic variations ==

Rare human genetic mutations are catalogued in the human genetic variation databases which can reportedly result in creation or deletion of ITIM and ITAMs. == Examples ==

Examples shown below list both proteins that contain the ITAM themselves and proteins that use ITAM-based signalling with the help of associated proteins which contain the motif. CD3γ, CD3δ, CD3ε, TYROBP (DAP12), FcαRI, FcγRI, FcγRII, FcγRIII, Dectin-1, CLEC-1, CD28, CD72 == References ==