ITCH plays multifaceted roles in T cells.
The arrowhead from ITCH indicates positive regulation of the substrate protein, while the blunt head from ITCH indicates negative regulation of the substrate protein. Blue line indicates a K48-linked polyubiquitination of the substrate, while red line indicates a non-proteolytic linkage. The arrowhead towards ITCH indicates a positive regulation of ITCH E3 ligase activity, while the blunt head towards ITCH indicates negative regulation of ITCH E3 ligase activity.