C2 domain present in NEDL1 (NEDD4-like ubiquitin protein ligase-1)
NEDL1 (AKA HECW1(HECT, C2 and WW domain containing E3 ubiquitin protein ligase 1)) is a newly identified HECT-type E3 ubiquitin protein ligase highly expressed in favorable neuroblastomas. In vertebrates it is found primarily in neuronal tissues, including the spinal cord. NEDL1 is thought to normally function in the quality control of cellular proteins by eliminating misfolded proteins. This is thought to be accomplished via a mechanism analogous to that of ER-associated degradation by forming tight complexes and aggregating misfolded proteins that have escaped ubiquitin-mediated degradation. NEDL1, is composed of a C2 domain, two WW domains, and a ubiquitin ligase Hect domain. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions.