Neuronal porosome proteome: Molecular dynamics and architecture

Porosomes are the universal secretory portals at the cell plasma membrane, where membrane-bound secretory vesicles transiently dock and fuse to expel intravesicular contents to the outside during cell secretion. In the past decade, the neuronal porosome complex, a 10-15nm cup-shaped lipoprotein structure has been isolated, its partial composition and 3D contour map determined, and it has been functionally reconstituted into artificial lipid membrane. Here we further determine the composition of the neuronal porosome proteome using immunoisolation and gel filtration chromatography, followed by tandem mass spectrometry. Results from the study demonstrate nearly 40 proteins to constitute the neuronal porosome proteome. Furthermore, interaction of proteins within the porosome and their resulting arrangement is predicted. The association and dissociation of proteins at the porosome following stimulation of cell secretion demonstrate the dynamic nature of the organelle.