Molecular recognition features are specific regions within IDPs that are regularly involved in binding and interaction. These regions are short sequences of approximately 5 to 25 residues that, upon binding, undergo a disorder-to-order transition resulting in secondary structure BMS-986034 formation stabilized by the binding. Regions that adopt an a-helical structure upon disorder-to-order transitions are specified as a-MoRFs. Being short helical stretches in longer disordered regions suggests that the C-terminal ITAM regions in CD79a and CD79b are a-MoRFs and that binding to a specific interaction partner or to the cell membrane could stabilize and potentially increase the helical propensity observed in these regions. In fact, our previously published data shows that the helical C-terminal ITAM region in CD79a becomes drastically more helical in the presence of the membrane-mimetic solvent TFE. Similar behavior has been observed for other a-MoRFs like a central region in myelin basic protein. Different regions in B- and T-cell receptor ITAMs have previously been observed to become helical upon interaction. A study by Gaul et al showed that a 12-residue peptide derived from the ITAM region of CD79a binds to the Src-kinase Lyn in an irregular helix-like conformation. Futterer et al showed that a small region located between the two tyrosines of a dually phosphorylated ITAM peptide derived from the CD3e chain of the T-cell receptor became helical when interacting with two SH2 domains of the kinase Syk. Further, the cytosolic domain of CD3e also contains an ITAM region that becomes phosphorylated upon activation. A study by Xu et al has shown that in its non-phosphorylated state, CD3eCD is bound to the plasma membrane. An NMR structure of CD3eCD bound to bicelles BMS-646786 presented in the same study showed that in the bound form, segments of the CD3eCD ITAM that were inserted into the lipid bilayer were structured with helical turns surrounding the two tyrosines. Especially the region surrounding the C-terminal ITAM tyrosine was helical when interacting with the membrane. It should be noted, however, that relevance of the helical conformation for the CD79a and CD79b ITAM regions in the context of membrane binding is doubtful, since there is evidence that neither the cytoplasmic regions of CD79a nor CD79b interact with the cell membrane.