Function and expression of a splicing variant of vesicular glutamate transporter 1

Satomi Moriyama, Masafumi Iharada, Hiroshi Omote, Yoshinori Moriyama, Miki Hiasa

Research output: Contribution to journalArticle

Abstract

Vesicular glutamate transporter (VGLUT) is an active transporter responsible for vesicular storage of glutamate in synaptic vesicles and plays an essential role in glutamatergic neurotransmission. VGLUT consists of three isoforms, VGLUT1, VGLUT2, and VGLUT3. The VGLUT1 variant, VGLUT1v, with an additional 75-base pair sequence derived from a second intron between exons 2 and 3, which corresponds to 25 amino acid residues in the 1st loop of VGLUT1, is the only splicing variant among VGLUTs, although whether VGLUT1v protein is actually translated at the protein level remains unknown. In the present study, VGLUT1v was expressed in insect cells, solubilized, purified to near homogeneity, and its transport activity was examined. Proteoliposomes containing purified VGLUT1v were shown to accumulate glutamate upon imposition of an inside-positive membrane potential (Δψ). The Δψ-driven glutamate uptake activity requires Cl and its pharmacological profile and kinetics are comparable to those of other VGLUTs. The retinal membrane contained two VGLUT1 moieties with apparent molecular masses of 65 and 57 kDa. VGLUT1v-specific antibodies against an inserted 25-amino acid residue sequence identified a 65-kDa immunoreactive polypeptide. Immunohistochemical analysis indicated that VGLUT1v immunoreactivity is present in photoreceptor cells and is associated with synaptic vesicles. VGLUT1v immunoreactivity is also present in pinealocytes, but not in other areas, including the brain. These results indicated that VGLUT1v exists in a functional state in rat photosensitive cells and is involved in glutamatergic chemical transmission.

Original languageEnglish
Pages (from-to)931-940
Number of pages10
JournalBiochimica et Biophysica Acta - Biomembranes
Volume1859
Issue number5
DOIs
Publication statusPublished - May 1 2017

Fingerprint

Vesicular Glutamate Transport Protein 1
Vesicular Glutamate Transport Proteins
Glutamic Acid
Synaptic Vesicles
Membranes
Amino Acids
Photoreceptor Cells
Molecular mass
Synaptic Transmission
Base Pairing
Membrane Potentials
Introns
Insects
Rats
Amino Acid Sequence
Exons
Brain
Protein Isoforms
Proteins
Pharmacology

Keywords

  • Photoreceptor cell
  • Pinealocyte
  • Splicing variant
  • Synaptic vesicle
  • Vesicular glutamate transporter
  • VGLUT1

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

Cite this

Function and expression of a splicing variant of vesicular glutamate transporter 1. / Moriyama, Satomi; Iharada, Masafumi; Omote, Hiroshi; Moriyama, Yoshinori; Hiasa, Miki.

In: Biochimica et Biophysica Acta - Biomembranes, Vol. 1859, No. 5, 01.05.2017, p. 931-940.

Research output: Contribution to journalArticle

Moriyama, Satomi ; Iharada, Masafumi ; Omote, Hiroshi ; Moriyama, Yoshinori ; Hiasa, Miki. / Function and expression of a splicing variant of vesicular glutamate transporter 1. In: Biochimica et Biophysica Acta - Biomembranes. 2017 ; Vol. 1859, No. 5. pp. 931-940.
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