AP2-mediated CD79-driven Endocytosis is Regulated in Cis via ITAM-embedded DCSM and QTAT motifs.

<p><u>Panel A</u>, Binding of AP2-btn to bead-captured GST bearing the indicated CD79a or CD79b cytoplasmic domains with the indicated mutations was determined as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0054938#pone-0054938-g003" target="_blank">Figure 3</a>. Binding is expressed as a percentage of wild type CD79a binding and represents the mean of 3 independent experiments ± SEM. Statistical comparisons were measured between the non-mutated CD79a or CD79b<sub>DCSM</sub> cytoplasmic domains and other samples. <u>Panels B and C</u>, Endocytosis of the indicated MHC class II-CD79 fusion proteins was analyzed and quantitated as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0054938#pone-0054938-g001" target="_blank">Figure 1</a>. Statistical comparisons were made between the reporter protein expressing the wild type CD79a or CD79b cytoplasmic domains and other reporter proteins. <u>Panel D</u>, Diagrammatic representation of <i>cis</i> and <i>trans</i> regulation of BCR AP2 binding and endocytosis. The open arrows indicate <i>cis</i> regulation by the DCSM and QTAT regulatory motifs. The closed arrows represent <i>trans</i> regulation of the endocytic activity of each cytoplasmic domain by the presence of the partner cytoplasmic domain.</p>