Spondin 1 (SPON1)

Spondin-1 is a protein contains 807 aminoacids and is structurally composed of six thrombospondin domains, one reelin domain, and one spondin domain.The deduced 624-amino acid partial SPON1 protein shares 96.8% amino acid sequence identity with the rat F-spondin precursor across 624 residues.SPON1 expression in lung, lower expression in brain, heart, kidney, liver, and testis, and lowest expression in pancreas, skeletal muscle, and ovary; no expression was found in spleen. In vitro binding assays using mutated human proteins confirmed that SPON1 specifically bound to the central APP domain (CAPPD). SPON1 inhibited APP cleavage by BACE1, the primary beta-secretase involved in APP processing. Binding also impaired APP- and FE65-dependent transactivation of the chromosome remodeling factor TIP60 .