Neuronal Porosome Complex: Secretory Machinery at the Nerve Terminal.

Neuronal porosomes are 15 nm cup-shaped lipoprotein secretory machines composed of nearly 30 proteins present at the presynaptic membrane, that have been investigated using multiple imaging modalities, such as electron microscopy, atomic force microscopy, and solution X-ray. Synaptic vesicles transiently dock and fuse at the base of the porosome cup facing the cytosol, by establishing a fusion pore for neurotransmitter release. Studies on the morphology, dynamics, isolation, composition, and reconstitution of the neuronal porosome complex provide a molecular understanding of its structure and function. In the past twenty years, a large body of evidence has accumulated on the involvement of the neuronal porosome proteins in neurotransmission and various neurological disorders. In light of these findings, this review briefly summarizes our current understanding of the neuronal porosome complex, the secretory nanomachine at the nerve terminal.