1. The Vesicular Monoamine Transporter VMAT2 and Vesicular Acetylcholine Transporter VAChT Are Sorted to Separate Vesicle Populations in PC12 Cells
- Author
-
Tao-Cheng Jh and Lee E. Eiden
- Subjects
education.field_of_study ,biology ,Population ,Adrenergic Neurons ,Synaptic vesicle ,Cell biology ,Vesicular monoamine transporter ,Monoamine neurotransmitter ,nervous system ,Biochemistry ,Vesicular acetylcholine transporter ,Synaptophysin ,biology.protein ,Cholinergic ,education - Abstract
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.
- Published
- 1997