Summary
The neurotransmitter dopamine (DA) controls many central nervous system
functions through three major pathways in the brain, the tuberoinfundibular, the
nigrostriatal and the mesocorticolimic (mesocortical and mesolimbic). Each is
associated with different processes, and dysfunction can lead to varying
diseases and disorders. There are five known DA receptors, D2 (D2R) is one of
the most abundant DA receptors in the brain, and is thus an important
pharmacological target for many central nervous system diseases. Most of the
clinically efficacious antipsychotics used for the treatment of schizophrenia and
Parkinson's disease, which are associated with the mesocorticolimbic and
nigrostriatal pathways, are D2R agonists or antagonists. In addition, several
drugs abused by humans (ie. psychostimulants such as cocaine and
methamphetamine) affect DA neurotransmission in the mesolimbic pathway, due
to their effects on reward-related behaviours. Therefore D2R is also a focus for
the discovery of pharmacological treatments for substance abuse of a certain
class of drugs and addiction disorders for which there are none currently
available. The goal of this proposal is to clone, express and purify active-state
stabilized D2R in quantities amenable to pursue initial crystallization trials. To
obtain active-state stabilized protein crystals, D2R will be bound with agonist and
complexed with purified G-protein and/or a stabilizing nanobody. This will enable
our longer term goal of x-ray crystallographic structure determination and the
discovery of D2R selective small molecule ligands for the treatment of substance
abuse disorders.
This proposal is in response to the Funding Opportunity Announcement PA-16-
302: PHS 2016-02 Omnibus Solicitation of the NIH, CDC, FDA, and ACF for
Small Business Innovation Research Grant Appplications (Parent SBIR
[R43/R44]).