RGD Reference Report - Directed evolution reveals hidden properties of VMAT, a neurotransmitter transporter. - Rat Genome Database

Send us a Message

Submit Data |  Help |  Video Tutorials |  News |  Publications |  Download |  REST API |  Citing RGD |  Contact   

Directed evolution reveals hidden properties of VMAT, a neurotransmitter transporter.

Authors: Gros, Y  Schuldiner, S 
Citation: Gros Y and Schuldiner S, J Biol Chem. 2010 Feb 12;285(7):5076-84. Epub 2009 Dec 10.
RGD ID: 5130957
Pubmed: (View Article at PubMed) PMID:20007701
DOI: Full-text: DOI:10.1074/jbc.M109.081216

The vesicular neurotransmitter transporter VMAT2 is responsible for the transport of monoamines into synaptic and storage vesicles. VMAT2 is the target of many psychoactive drugs and is essential for proper neurotransmission and survival. Here we describe a new expression system in Saccharomyces cerevisiae that takes advantage of the polyspecificity of VMAT2. Expression of rVMAT2 confers resistance to acriflavine and to the parkinsonian toxin 1-methyl-4-phenylpyridinium (MPP(+)) by their removal into the yeast vacuole. This expression system allowed identification of a new substrate, acriflavine, and isolation of mutants with modified affinity to tetrabenazine (TBZ), a non-competitive inhibitor of VMAT2 that is used in the treatment of various movement disorders including Tourette syndrome and Huntington chorea. Whereas one type of mutant obtained displayed decreased affinity to TBZ, a second type showed only a slight decrease in the affinity to TBZ, displayed a higher K(m) to the neurotransmitter serotonin, but conferred increased resistance to acriflavine and MPP(+). A protein where both types of mutations were combined (with only three amino acid replacements) lost most of the properties of the neurotransmitter transporter (TBZ-insensitive, no transport of neurotransmitter) but displayed enhanced resistance to the above toxicants. The work described here shows that in the case of rVMAT2, loss of traits acquired in evolution of function (such as serotonin transport and TBZ binding) bring about an improvement in older functions such as resistance to toxic compounds. A process that has taken millions of years of evolution can be reversed by three mutations.


Gene-Chemical Interaction Annotations    
serotonin  (EXP,ISO)
tetrabenazine  (EXP,ISO)

Gene Ontology Annotations    

Biological Process

Cellular Component
membrane  (IDA)

Molecular Function

Objects Annotated

Genes (Rattus norvegicus)
Slc18a2  (solute carrier family 18 member A2)

Genes (Mus musculus)
Slc18a2  (solute carrier family 18 (vesicular monoamine), member 2)

Genes (Homo sapiens)
SLC18A2  (solute carrier family 18 member A2)

Additional Information