Interaction between the vesicular glutamate transporter type 1 and endophilin A1, a protein essential for endocytosis.
In the nerve terminal, neurotransmitter is actively packaged into synaptic vesicles before its release by Ca2+-dependent exocytosis. The three vesicular glutamate transporters (VGLUT1, -2 and -3) are highly conserved proteins that display similar bioenergetic and pharmacological properties but are expressed in different brain areas. We used the divergent C-terminus of VGLUT1 as a bait in a yeast two-hybrid screen to identify and map the interaction between a proline-rich domain of VGLUT1 and the Src homology domain 3 (SH3) domain of endophilin. We further confirmed this interaction by using different glutathione-S-transferase-endophilin fusion proteins to pull down VGLUT1 from rat brain extracts. The expression profiles of the two genes and proteins were compared on rat brain sections, showing that endophilin is most highly expressed in regions and cells expressing VGLUT1. Double immunofluorescence in the rat cerebellum shows that most VGLUT1-positive terminals co-express endophilin, whereas VGLUT2-expressing terminals are often devoid of endophilin. However, neither VGLUT1 transport activity, endophilin enzymatic activity nor VGLUT1 synaptic targeting were altered by this interaction. Overall, the discovery of endophilin as a partner for VGLUT1 in nerve terminals strongly suggests the existence of functional differences between VGLUT1 and -2 terminals in their abilities to replenish vesicle pools.
Vinatier
Jacqueline
J
INSERM U513, Neurobiology and Psychiatry, Faculté de Médecine, Créteil, France.
Herzog
Etienne
E
Plamont
Marie-Aude
MA
Wojcik
Sonja M
SM
Schmidt
Anne
A
Brose
Nils
N
Daviet
Laurent
L
El Mestikawy
Salah
S
Giros
Bruno
B
D000217:Acyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D002460:Cell Line; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology / Q000378:metabolism; D004705:Endocytosis / Q000502:physiology*; D005786:Gene Expression Regulation / Q000502:physiology; D018698:Glutamic Acid / Q000378:metabolism*; D008297:Male; D017729:Presynaptic Terminals / Q000378:metabolism*; D017434:Protein Structure, Tertiary / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D009435:Synaptic Transmission / Q000502:physiology*; D013572:Synaptic Vesicles / Q000378:metabolism*; D050598:Vesicular Glutamate Transport Protein 1 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D050599:Vesicular Glutamate Transport Protein 2 / Q000378:metabolism
D011993:Recombinant Fusion Proteins; C493475:Slc17a6 protein, rat; C493466:Slc17a7 protein, rat; D050598:Vesicular Glutamate Transport Protein 1; D050599:Vesicular Glutamate Transport Protein 2; D018698:Glutamic Acid; D000217:Acyltransferases; C018764:2-acylglycerophosphate acyltransferase