Recombinant Human Neuronal Pentraxin 1 Protein, CF

Neuronal Pentraxin (NPTX1; also called NP1) is a 47‑50 kDa secreted glycoprotein within the Pentraxin family (1, 2). NPTX1 is co‑expressed and forms heteromultimers with the related secreted protein, NPTX2/NARP, and type II transmembrane protein, NPTXR (Neuronal Pentraxin Receptor) at excitatory synapses (2‑5). Human NPTX1 is a 432 amino acid (aa) protein that includes a 22 aa signal sequence and a 410 aa secreted mature protein with one calcium‑binding Pentraxin domain (1, 2). Mature human NPTX1 shares 97% aa sequence identity with mouse, rat, bovine, porcine and canine NPTX1. NPTX1 is produced by hippocampal, cerebral and cerebellar neurons, retinal ganglia and the inner nuclear layer of the retina (1, 4‑10). NPTX1 is up‑regulated by conditions that promote neuronal apoptosis, such as amyloid‑ beta, hypoxia/ischemia, and reduction of neuronal activity by potassium deprivation, and it participates in apoptosis (7‑10). It is enriched on presynaptic axonal membranes where it forms complexes with NPTXR (3, 5). The complexes promote synaptogenesis by recruiting subunits of AMPA‑type glutamate receptors (AMPAR) (5, 11). Synaptic activity stimulates metabotropic receptors (mGluR), which then activate NPTXR cleavage and release of the complex from the membrane (4, 11). Pentraxin domains of NPTX1/2 within the complex mediate adhesion to AMPAR, while the soluble (but not transmembrane) form of NPTXR within the complex mediates AMPAR endocytosis (3, 11).