Comparison of the physicochemical and lipid-binding properties of lipid-interacting and non–lipid-interacting ITAMs and ITIMs
| Signaling molecule . | ITIM/ITAM . | Sequence . | Lipid interaction . | pI* . | Proximal basic pair† . |
|---|---|---|---|---|---|
| CD3ϵ | ITAM | PNPDYEPIRKGQRDLYSGLNQRR | Yes | 9.7 | Yes |
| TCRζ | ITAM 1 | QNQLYNELNLGRREEYDVLDKRR | Yes | 6.3 | Yes |
| PECAM-1 | C-terminal ITIM | TETVYSEVRKAVPDAVESRYSRT | Yes | 5.9 | Yes |
| TCRζ | ITAM 3 | HDGLYQGLSTATKDTYDALHMQA | No | 5.1 | No |
| PECAM-1 | N-terminal ITIM | SDVQYTEVQVSSAESHKDLGKKD | No | 4.8 | No |
| TCRζ | ITAM 2 | QEGLYNELQKDKMAEAYSEIGMK | No | 4.6 | No |
| CD3δ | ITAM | NDQVYQPLRDRDDAQYSHLGGNW | No | 4.6 | No |
| CD3γ | ITAM | NDQLYQPLKDREDDQYSHLQGNQ | No | 4.4 | No |
| BCR Igβ | ITAM | EDHTYEGLDIDQTATYEDIVTLR | No | 3.9 | No |
| BCR Igα | ITAM | DENLYEGLNLDDCSMYEDISRGL | No | 3.6 | No |
| Signaling molecule . | ITIM/ITAM . | Sequence . | Lipid interaction . | pI* . | Proximal basic pair† . |
|---|---|---|---|---|---|
| CD3ϵ | ITAM | PNPDYEPIRKGQRDLYSGLNQRR | Yes | 9.7 | Yes |
| TCRζ | ITAM 1 | QNQLYNELNLGRREEYDVLDKRR | Yes | 6.3 | Yes |
| PECAM-1 | C-terminal ITIM | TETVYSEVRKAVPDAVESRYSRT | Yes | 5.9 | Yes |
| TCRζ | ITAM 3 | HDGLYQGLSTATKDTYDALHMQA | No | 5.1 | No |
| PECAM-1 | N-terminal ITIM | SDVQYTEVQVSSAESHKDLGKKD | No | 4.8 | No |
| TCRζ | ITAM 2 | QEGLYNELQKDKMAEAYSEIGMK | No | 4.6 | No |
| CD3δ | ITAM | NDQVYQPLRDRDDAQYSHLGGNW | No | 4.6 | No |
| CD3γ | ITAM | NDQLYQPLKDREDDQYSHLQGNQ | No | 4.4 | No |
| BCR Igβ | ITAM | EDHTYEGLDIDQTATYEDIVTLR | No | 3.9 | No |
| BCR Igα | ITAM | DENLYEGLNLDDCSMYEDISRGL | No | 3.6 | No |
Properties of ITAM sequences were modified from Sigalov et al.35
ITAM and ITIM tyrosine (Y) residues are highlighted in bold. The basic amino acid residues, arginine (R) and lysine (K), are underlined.
Isoelectric points (pI) were calculated with the Compute pI/MW tool using the Swiss Institute of Bioinformatics ExPASy Proteomics Server (http://expasy.org/tools/pi_tool.html).
Proximal basic pair is defined as 2 adjacent basic amino acid residues either between the 2 ITAM tyrosine residues or within 5 residues of an ITIM tyrosine residue. Note that the sequence between the 2 ITAM tyrosine residues in TCRζ ITAM 2, CD3δ, and CD3γ contains 2 basic amino acid residues but that they are separated by an acidic aspartic acid (D) residue.