The proteome of the presynaptic active zone: from docked synaptic vesicles to adhesion molecules and maxi‐channels

Abstract

The presynaptic proteome controls neurotransmitter release and the short and long term structural and functional dynamics of the nerve terminal. Using a monoclonal antibody against synaptic vesicle protein 2 we immunopurified a presynaptic compartment containing the active zone with synaptic vesicles docked to the presynaptic plasma membrane as well as elements of the presynaptic cytomatrix. Individual protein bands separated by sodium dodecyl sulfate–polyacrylamide gel electrophoresis were subjected to nanoscale‐liquid chromatography electrospray ionization‐tandem mass spectrometry. Combining this method with 2‐dimensional benzyldimethyl‐n‐hexadecylammonium chloride/sodium dodecyl sulfate‐polyacrylamide gel electrophoresis and matrix‐assisted laser desorption ionization time of flight and immunodetection we identified 240 proteins comprising synaptic vesicle proteins, components of the presynaptic fusion and retrieval machinery, proteins involved in intracellular signal transduction, a large variety of adhesion molecules and proteins potentially involved in regulating the functional and structural dynamics of the pre‐synapse. Four maxi‐channels, three isoforms of voltage‐dependent anion channels and the tweety homolog 1 were co‐isolated with the docked synaptic vesicles. As revealed by in situ hybridization, tweety homolog 1 reveals a distinct expression pattern in the rodent brain. Our results add novel information to the proteome of the presynaptic active zone and suggest that in particular proteins potentially involved in the short and long term structural modulation of the mature presynaptic compartment deserve further detailed analysis.

Global Analysis of S-nitrosylation Sites in the Wild Type (APP) Transgenic Mouse Brain-Clues for Synaptic Pathology

“…Synaptosomes are a well-recognized model for studies of synaptic complexity in the brain (86,87). They contain complete presynaptic terminals, with postsynaptic membranes and densities, as well as other components necessary to store, release, and retain neurotransmitters.…”

The actin cytoskeleton in presynaptic assembly

“…The presynaptic compartment contains hundreds of proteins, including those associated with synaptic vesicles, channels, SNAREs, active zone cytomatrix components, endocytic machinery, and adhesion molecules. [52][53][54][55] While studies have demonstrated that F-actin is required for the proper development and organization of the presynaptic components of synapses, as we will discuss in the ensuing sections, 31,33,43 there is disagreement over the localization of F-actin in the presynaptic compartment.…”

“…63 Similarly, several proteomic studies have identified actin as a component of the synaptic vesicle and active zone proteomes. 52,54,55,[64][65][66][67] Interestingly, in lamprey receptor-and cadherin-mediated synaptic adhesion, discussed below, are beginning to be elucidated. IG adhesion receptors influence synapse formation through cytoskeletal interactions.…”

Proteomic analysis of the presynaptic active zone

“…1). The docked vesicles represent a presynaptic compartment containing the active zone with synaptic vesicles docked to the presynaptic plasma membrane (Morciano et al 2009). The purity of the isolated free and docked vesicles was evaluated by electron microscopy, marker protein analysis (Morciano et al 2005;Morciano et al 2009), and correlation proWling (Burré et al 2006b).…”

“…In addition, we have developed protocols for a proteomic analysis of the presynaptic active zone containing the docked synaptic vesicles and the presynaptic membrane (Morciano et al 2005;Burré et al 2006b;Morciano et al 2009). …”