Recombinant Mouse Notch-2 Fc Chimera Protein, CF

Notch-2 is a 300 kDa type I transmembrane glycoprotein that is one of four Notch homologues involved in development (1 - 3). Although Notch proteins are structurally and functionally similar, deletion of either Notch-1 or Notch-2 is lethal, demonstrating that not all functions overlap (4, 5). Mice with hypomorphic Notch-2 show defects in development of kidney, heart and eye (6). Notch-2 is upregulated in mature B cells and is critical for differentiation to splenic marginal zone B cells (7). Notch-2 is also preferentially expressed in choroid plexus epithelia and neuronal precursors (8, 9). Mouse Notch-2 is synthesized as a 2470 amino acid (aa) precursor that contains a 25 aa signal sequence, a 1652 aa extracellular domain (ECD), a 21 aa transmembrane (TM) segment, and a 772 aa cytoplasmic domain. The ECD contains 35 EGF-like repeats and three Lin-12/Notch repeats, while the cytoplasmic region shows six ankyrin repeats, a glutamine-rich domain and a PEST sequence. Binding of ligands, including Jagged and Delta-like molecules, has been localized to the 11^th and 12^th EGF-like repeats of human Notch-1 (corresponding to aa 413 - 492 in mouse Notch-2) (10). Notch receptors undergo post-translational furin-type proteolytic cleavage (11). This forms a heterodimer through the interaction of a hydrophobic area in the ligand-binding extracellular region with the TM/cytoplasmic portion (11, 12). Upon ligand binding, additional sequential proteolysis by TNF-converting enzyme (ADAM-17) and the presenilin-dependent gamma-secretase results in the release of the Notch intracellular domain (NICD) which translocates into the nucleus, activating transcription of Notch-responsive genes (13). Mouse Notch-2 ECD (aa 26 - 528) shares 93%, 96%, 92% and 92% aa identity with the corresponding regions of human, rat, canine, and bovine Notch-2, respectively. This region also exhibits 55 - 58% aa identity with mouse Notch-1 and Notch-3.