ZAP-70 ubiquitination.

<p>(a) ZAP-70 kinase domain ubiquitination sites. Proteasome-insensitive sites are shown in yellow, proteasome-sensitive sites and those where proteasome sensitivity is unknown are shown in red. K377 and K476 are labeled. (b) Most common proteasome-insensitive kinase ubiquitination sites mapped onto the ZAP-70 kinase structure. The color indicates how many kinases are ubiquitinated at this site (light blue = 2, grey blue = 3, dark blue = 4, mauve = 6). Not all of the sites are ubiquitinated on ZAP-70, but the most common site, K476, is. In both figures the C-helix is represented with an orange cylinder, K369 on strand β3 of the N-lobe and E386 on the C-helix (forming the salt bridge that holds the C-helix in place) are shown with orange sticks, and the activation loop is shown in pink.