The Missing Link(er): A Return to Symmetry in Antigen Receptor Signaling?

Table 1.

Comparison of Tyrosine-Containing Motifs Found in Human LAT and NTAL/LAB Likely Involved in Protein Docking

LAT	NTAL/LAB
Phosphorylated YxN motifs (where x is any amino acid) are considered optimal binding sites for Grb2. ^¶Indicates residues responsible for binding to PLC–γ. ^†Indicates residues responsible for binding to Grb2. ^‡Indicates residues responsible for binding Gads. From (10). pY indicates those tyrosines that have been demonstrated to be phosphorylated and may act as binding sites. Although specific attributions of protein binding to particular phosphotyrosine residues in NTAL/LAB have not been elucidated, the sequence motif flanking Y¹³⁶ most closely resembles LAT at Y²²⁶, whereas the sequence flanking Y²³³ (NTAL/LAB) most closely resembles those found in LAT at Y¹⁷¹, and Y¹⁹¹. Adapted from (19). NTAL/LAB binds to Grb2, Sos1, and Gab1 from B cells and myeloid cells, and to c-Cbl from myeloid cells (20).
₁₁₀ YENE₁₁₃	₅₈ YSLV₆₁
₁₂₇ YHNT₁₃₀	₉₅ YQNF₉₈
_132p YLVV₁₃₆^¶	₁₁₈ YYNW₁₂₁
_171p YVNV₁₇₄^†	₁₃₆ YENV₁₃₉
_191p YVNV₁₉₄^†,‡	₁₉₃ YQNS₁₉₆
_226p YENL₂₂₉^†,‡	₂₃₃ YVNG₂₃₆