Exocyst complex component 3

EXOC3 (exocyst complex component 3) is a 745-amino acid protein that functions as a structural component of the exocyst complex, which mediates the docking of exocytic vesicles at the plasma membrane (UniProt: O60645). The exocyst is a conserved octameric complex essential for polarized secretion and cell-surface protein delivery across tissues. EXOC3 localizes to multiple subcellular compartments and participates in vesicle trafficking pathways critical for neuronal function and synaptic homeostasis.

In the context of Alzheimer's Disease, EXOC3 shows reduced abundance in post-mortem AD brain tissue compared to age-matched controls, with a mean log2 fold-change of −0.42 across subcellular fractions (Chaparral AD proteomics). This downregulation suggests diminished exocytic capacity in AD brain, potentially compromising secretory pathway function and protein delivery to synaptic terminals. Dysregulation of exocytic machinery has been implicated in amyloid-beta and tau pathology, as impaired vesicular trafficking may exacerbate protein aggregation and clearance defects characteristic of neurodegeneration. The directional evidence supports a loss-of-function contribution to AD pathophysiology.