| First Author | Salazar G | Year | 2005 |
| Journal | J Cell Sci | Volume | 118 |
| Issue | Pt 9 | Pages | 1911-21 |
| PubMed ID | 15860731 | Mgi Jnum | J:98044 |
| Mgi Id | MGI:3576988 | Doi | 10.1242/jcs.02319 |
| Citation | Salazar G, et al. (2005) Vglut1 and ZnT3 co-targeting mechanisms regulate vesicular zinc stores in PC12 cells. J Cell Sci 118(Pt 9):1911-21 |
| abstractText | The lumenal ionic content of an organelle is determined by its complement of channels and transporters. These proteins reach their resident organelles by adaptor-dependent mechanisms. This concept is illustrated in AP-3 deficiencies, in which synaptic vesicle zinc is depleted because the synaptic-vesicle-specific zinc transporter 3 does not reach synaptic vesicles. However, whether zinc transporter 3 is the only membrane protein defining synaptic-vesicle zinc content remains unknown. To address this question, we examined whether zinc transporter 3 and the vesicular glutamate transporter Vglut1 (a transporter that coexists with zinc transporter 3 in brain nerve terminals) were co-targeted to synaptic-like microvesicle fractions in PC12 cells. Deconvolution microscopy and subcellular fractionation demonstrated that these two transporters were present on the same vesicles in PC12 cells. Vglut1 content in synaptic-like microvesicle fractions and brain synaptic vesicles was partially sensitive to pharmacological and genetic perturbation of AP-3 function. Whole-cell flow-cytometry analysis of PC12 cell lines expressing zinc transporter 3, Vglut1 or both showed that vesicular zinc uptake was increased by Vglut1 expression. Conversely, production of zinc transporter 3 increased the vesicular uptake of glutamate in a zinc-dependent fashion. Our results suggest that the coupling of zinc transporter 3 and Vglut1 transport mechanisms regulates neurotransmitter content in secretory vesicles. |
