NEDD4 is a 221 amino acid, Golgi-associated protein which contains three transmembrane domains in its carboxy-terminus and two PY motifs in its amino-terminus. NEDD4 may play a role in Golgi structure and function. It binds the WW domains of a number of NEDD4 family members called HECT-type E3 ubiquitin ligases. NEDD4 is strongly expressed in surviving neurons around an injury site, which suggests that ubiquitination may be a possible survival strategy and that NEDD4 may act as a neuroprotective protein. It may also have an effect on the function of Itch, another E3 ubiquitin ligase. Expression of NEDD4 and its association with Itch may be promoted by T cell activation.
