protein_function: Functions as a cell surface receptor and performsphysiological functions on the surface of neurons relevant toneurite growth, neuronal adhesion and axonogenesis. Involved incell mobility and transcription regulation through protein-proteininteractions. Can promote transcription activation through bindingto APBB1-KAT5 and inhibits Notch signaling through interactionwith Numb. Couples to apoptosis-inducing pathways such as thosemediated by G(O) and JIP. Inhibits G(o) alpha ATPase activity (Bysimilarity). Acts as a kinesin I membrane receptor, mediating theaxonal transport of beta-secretase and presenilin 1. Involved incopper homeostasis,oxidative stress through copper ion reduction.In vitro, copper-metallated APP induces neuronal death directly oris potentiated through Cu(2+)-mediated low-density lipoproteinoxidation. Can regulate neurite outgrowth through binding tocomponents of the extracellular matrix such as heparin andcollagen I and IV. The splice isoforms that contain the BPTIdomain possess protease inhibitor activity. Induces a AGER-dependent pathway that involves activation of p38 MAPK, resultingin internalization of amyloid-beta peptide and leading tomitochondrial dysfunction in cultured cortical neurons. ProvidesCu(2+) ions for GPC1 which are required for release of nitricoxide (NO) and subsequent degradation of the heparan sulfatechains on GPC1..
Amyloid precursor protein(APP) is an integral membrane protein expressed in many tissues and concentrated in the synapses of neurons. Its primary function is not known, though it has been implicated as a regulator of synapse formation, neural plasticity and iron export. APP is best known and most commonly studied as the precursor molecule whose proteolysis generates beta amyloid(Abeta), a 39- to 42-amino acid peptide whose amyloid fibrillar form is the primary component of amyloid plaques found in the brains of Alzheimer"s disease patients. APP undergoes posttranslational proteolytic processing by alpha-, beta-, and gamma-secretases. Alpha-secretase generates soluble amyloid protein, while beta- and gamma-secretases generate APP components with amyloidogenic features. These 2 processing pathways are mutually exclusive.