Beta-soluble NSF attachment protein

Beta-soluble NSF attachment protein (SNAP-beta; encoded by NAPB) is a 298-amino-acid protein required for vesicular transport between the endoplasmic reticulum and the Golgi apparatus (UniProt: Q9H115). It functions as a core component of the SNARE trafficking machinery, facilitating membrane-docking and fusion events essential for intracellular protein transport.

In addition to its canonical trafficking role, NAPB is associated with developmental and epileptic encephalopathy 107 (DEE107; MIM 620033), an autosomal recessive disorder characterized by early-onset refractory seizures, severe developmental delay, profound intellectual disability, and progressive microcephaly. This disease association underscores the protein's critical importance in neuronal function and development (UniProt: Q9H115).

In Alzheimer's disease, NAPB is significantly downregulated in human post-mortem AD brain compared to age-matched controls (mean log2 fold-change: −0.70; Chaparral AD proteomics). The downregulation was observed across the subcellular fractionation experiment (1 of 4 fractions analyzed). This reduction may reflect impaired vesicular trafficking and secretory pathway dysfunction in AD pathology.