SV31 is a Zn2+-binding synaptic vesicle protein.

Abstract

We recently identified in a proteomic screen a novel synaptic vesicle membrane protein of 31 kDa (SV31) of unknown function. According to its membrane topology and its phylogenetic relation SV31 may function as a vesicular transporter. Based on its amino acid sequence similarity to a prokaryotic heavy metal ion transporter we analyzed its metal ion-binding properties and show that recombinant SV31 binds the divalent cations Zn(2+) and Ni(2+) and to a minor extent Cu(2+), but not Fe(2+), Co(2+), Mn(2+), or Ca(2+). Zn(2+)-binding of SV31 in viable cells was verified following heterologous transfection of pheochromocytoma cells 12 (PC12) with recombinant red fluorescent SV31 (SV31-RFP) and the fluorescent zinc indicator FluoZin-3. Sucrose density gradient fractionation of SV31-RFP-transfected PC12 cells revealed a partial overlap of SV31-RFP with synaptic-like vesicle markers and the early endosome marker rab5. Immunocytochemical analysis demonstrated a punctuate distribution in the cell soma and in neuritic processes and in addition in a compartment in vicinity to the plasma membrane that was immunopositive also for synaptosomal-associated protein 25 (SNAP-25) and syntaxin1A. Our data suggest that SV31 represents a novel Zn(2+) -binding protein that in PC12 cells is targeted to endosomes and subpopulations of synaptic-like microvesicles.

• Authors: Joern Barth, Herbert Zimmermann, Walter Volknandt
• Journal: Journal of neurochemistry (J Neurochem) Vol. 118 Issue 4 Pg. 558-70 (Aug 2011) ISSN: 1471-4159 [Electronic] England
• PMID: 21668449 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2011 The Authors. Journal of Neurochemistry © 2011 International Society for Neurochemistry.

Chemical References

• Carrier Proteins
• Cations, Divalent
• FluoZin-3
• Membrane Proteins
• Nerve Tissue Proteins
• Polycyclic Compounds
• Recombinant Proteins
• Tmem163 protein, rat
• zinc-binding protein
• Zinc

Topics

• Amino Acid Sequence
• Animals
• CHO Cells
• Carrier Proteins (metabolism, physiology)
• Cations, Divalent (metabolism)
• Centrifugation, Density Gradient
• Chromatography, Affinity
• Cloning, Molecular
• Computer Simulation
• Cricetinae
• Cricetulus
• Membrane Proteins (chemistry, metabolism, physiology)
• Microscopy, Fluorescence
• Molecular Sequence Data
• Nerve Tissue Proteins (chemistry, metabolism, physiology)
• PC12 Cells
• Polycyclic Compounds
• Protein Binding
• Protein Conformation
• Rats
• Recombinant Proteins (chemistry, metabolism)
• Subcellular Fractions (metabolism)
• Synaptic Vesicles (metabolism, physiology)
• Transfection
• Zinc (metabolism)