Figure 3: Relative sequence length and putative phosphorylation sites of the C-terminal region of class A 7TM receptors, chemokine receptors and virus-encoded chemokine receptors. The vertical axis displays the number of amino acids of the C-terminus (blue), defined as being after the highly conserved proline of the NPxxY-motif, and the number of serine, threonine and tyrosine in this region (beige). The horizontal axis displays the average of 334 non-olfactory class A 7TM receptors (1), the chemokine receptors (2–20) and the viral chemokine receptors (21–52). For further information about specific receptors and GenBank accession number please see Table 1.