NEDD4 Binding Protein 3 (N4BP3)

Nedd4 is a HECT domain-containing ubiquitin ligase that mediates ubiquitylation and proteasome degradation of target proteins. The molecular basis for the interaction of Nedd4 with substrates lies in its WW domains, which can bind proline-rich (PY) domains in target proteins. Nedd4 is a developmentally expressed protein and may have a fundamental role to play in embryonic processes. However, whether Nedd4 has such a function is currently unknown, in part because few developmentally regulated ubiquitylation substrates have been identified or characterized.  However, this protein clearly associates with Nedd4 through its PY domains and can alter the location of Nedd4 in cells, suggesting a role other than as a ubiquitylation substrate.