The Vesicular Monoamine Transporter VMAT2 and Vesicular Acetylcholine Transporter VAChT Are Sorted to Separate Vesicle Populations in PC12 Cells

https://doi.org/10.1016/S1054-3589(08)60740-1Get rights and content

Publisher Summary

Vesicular transporters of transmitters are excellent markers for functional neuroanatomy and for potential identification of vesicular contents at the subcellular level. In this chapter, the distribution of two vesicular monoamine transporters (VMAT1 and VMAT2), a vesicular acetylcholine transporter (VAChT), a transmembrane transporter (SV2), and two other proteins have been examined. VMAT1 is endogenous in PC12 cells, and it is abundant on LDCVs. This location of VMAT1 is consistent with the fact that LDCVs take up norepinephrine in PC12 cells. On the otherhand, VMAT2 is not endogenous in PC12 cells. In the chapter VMAT2 has been expressed in PC12 cells under a constitutive viral promoter to see if it would be sorted to secretory vesicles. In the transfected PC12 cells, VMAT2 is preferentially localized on the LDCVs and not on the SSVs. The lack of a prominent population of VMAT2-positive synaptic vesicles in these PC12 cells is in contrast to the distribution of endogenous VAMT2 in central and peripheral adrenergic neurons. In these adrenergic neurons in vivo, VMAT2 is localized on LDCVs and on a distinct population of catecholamine-containing synaptic vesicles that are termed small dense-core vesicles (SDCVs). The chapter also analyzes subcellular distributions of three other SSV components, synaptophysin, SV2, and VAChT. Proteins destined for cholinergic SSVs may arrive via LDCVs or constitutive vesicles and recycle through the early endosomes, where they are concentrated for inclusion in the SSV membrane. Proteins in this category include SV2, VAChT, and synaptophysin. VMAT2, the neuronal VMAT in LDCVs and SDCVs of noradrenergic neurons, is not targeted to cholinergic SSVs when expressed in PC12 cells. Thus, SDCVs of noradrenergic neurons may represent a distinct population of synaptic vesicles that is biosynthetically separate from cholinergic SSVs in PC12 cells.

References (4)

There are more references available in the full text version of this article.

Cited by (17)

  • The Vesicular Acetylcholine Transporter Interacts with Clathrin-associated Adaptor Complexes AP-1 and AP-2

    2004, Journal of Biological Chemistry
    Citation Excerpt :

    The dileucine/phosphorylation motif of VAChT may also have a dual function; one of containing an internalization signal, but not via an AP-2 complex, and the other a signal for AP-1-dependent trafficking. An alternative pathway for VAChT trafficking, suggested by Tao-Cheng and Eiden (54) and by Varoque and Erickson (35), utilizes the regulated secretory sorting pathway, as do VMATs, instead of the constitutive secretory pathway, Fig. 10B. Electron microscopy studies showed endogenous VAChT, as well as transfected VAChT, appearing mainly in SLMVs, but also in LDCVs in PC12 cells (1, 35, 54).

  • Labeling and dynamic imaging of synaptic vesicle-like microvesicles in PC12 cells using TIRFM

    2004, Brain Research
    Citation Excerpt :

    The VAChT is a vesicle-specific, integral membrane protein that transports ACh into synaptic vesicles [10]. VAChT protein appears predominantly in SSVs/SLMVs [6,11,16,18,20] and has been considered an ideal, specific marker of this type of vesicles in various preparations including PC12 cells [6]. The GFP-tagged version of VAChT has been employed to label SLMVs in PC12 cells [12].

View all citing articles on Scopus
View full text