Fig. 5.

MSA of the amino acids in the cytoplasmic tail of the Ig-α co-receptor. The Ig-α cytoplasmic tail shows high conservation across tyrosine, serine, and threonine residues, and contains the ITAM domain. The TAM region, YXX(L/I)X6-12YXX(L/I), of the Ig-α ITAM is highly conserved across the 19 species analyzed and is boxed in black. This TAM region is involved in the primary kinase signaling through phosphorylation of Y182 and Y193, boxed in yellow. Two conserved tyrosine residues flanking the TAM region, Y176 within the ITAM and Y204 downstream of the ITAM are boxed in red, and are crucial for the downstream B cell intracellular signaling initiated by the ITAM and Src kinases. Serine and threonine phosphorylation within and just downstream of the TAM region of the ITAM, S191, S197, and T203, have been shown to regulate Ig-α ITAM signal transduction and are boxed in pink. Ig-α polypeptide sequences were scanned with MOTIF search server (http://motif.genome.jpz) and aligned with CLUSTAL W3.2 and BioEdit version 7.0.9.0