Definition:

Proton-coupled polyamine antiporter involved in the translocation of polyamines from cytosol into secretory vesicles prior to their release via exocytosis. Uses the electrochemical proton gradient generated by a V-type proton-pumping ATPase to couple the efflux of protons with the uptake of a polyamine molecule. Facilitates vesicular storage of spermine and spermidine in astrocytes with an impact on glutamatergic neuronal transmission and memory formation (By similarity). Upon antigen stimulation, regulates polyamine accumulation and release in mast cell secretory granules, which in turn potentiates mast cell degranulation and histamine secretion (By similarity).