Neurexophilin-3 Antibody

Neurexophilin-3 (NXPH-3) is a neuropeptide-like secreted glycoprotein in the neurexophilin family (1, 2). The 252 amino acid (aa) NXPH-3 precursor contains a 22 aa signal peptide, plus a 230 aa proprecursor that is likely cleaved at a basic motif, producing a 76 aa propeptide and a 154 aa mature protein (1). Mature rat NXPH-3 shares 99%, 95% and 92% aa identity with mouse, human and bovine NXPH-3, respectively. It contains motifs that are conserved among all neurexophilins, including three potential N-glycosylation sites in the N-terminal portion and six cysteines in the C-terminal portion (1). NXPH-3 is expressed selectively in subplate-derived neurons in the cortex, granule cells in the vestibulocerebellum, and Cajal-Retzius cells during development (3). NXPH-1 is the neurexophilin most similar to NXPH-3, sharing 69% aa identity within the mature region. Expression of NXPH-1 and NXPH-3 does not appear to overlap, with NXPH-1 expression occurring mainly by cells that resemble inhibitory interneurons (2-4). Both are tightly bound extracellular ligands of alpha -neurexins, synaptic transmembrane molecules that are essential for calcium-triggered neurotransmitter release (1, 5, 6). Genetic deletion of NXPH-1 and/or NXPH-3 produces no anatomical effect, although mice lacking NXPH-3 show specific defects in motor coordination (3, 4). Of the other known neurexophilins, NXPH-2 is not expressed in rodents, and NXPH-4 does not bind alpha -neurexins (1, 5).