Area of research
The main focus of the LølandLab is to elucidate the molecular mechanism underlying the function of neurotransmitter:sodium Symporters (NSSs). We wish to obtain a higher understanding of how these molecular motors are capable of transporting its substrate across the cell membrane and back into the presynaptic terminal. This includes how the process is coupled to the co-transport of Na+ and possibly Cl-, what role the ions have and which parts of this process that induces the protein conformational changes controlling the translocation mechanism. Compelling evidence also suggests that K+ is counter transported. We wish to elucidate this role and how it leads to an increased catalytic activity of the NSS.
A central part of this research is the elucidation of the binding sites for substrates, ions and inhibitors. We have a genuine interest in characterizing the binding mode of atypical dopamine transporter inhibitors (ADIs). They are interesting because they bind to the dopamine transporter as cocaine does, but they do not elicit any rewarding or stimulatory response, in fact, they can antagonize the effects of cocaine. This makes the ADIs good candidates for a medical treatment against cocaine addiction. We wish to seek out how they can do this.
An allosteric binding site is present in NSS proteins. We have been instrumental in the characterization of this site. Our ongoing research is focusing on the development of high-affinity allosteric ligands and elucidating how they can be used in the treatment of psychiatric diseases.
To address these issues, we use methods that include advanced biophysics on purified proteins and all aspects of biochemistry and molecular pharmacology on cell systems. We are able to purify membrane proteins from both bacterial (E. coli) and eukaryotic (HEK293expi cell suspension cultures) expression systems.
Specific methods include transition metal ion FRET, environmentally sensitive fluorophores, x-ray crystallography, microthermophoresis, protein reconstitution, nanodisc technologies, scintillation proximity assay, molecular pharmacology, cell-based transfection systems, standard molecular biology and biochemistry, etc.
- Identification of the binding sites for ions in LeuT
- Elucidating the catalytic activity of LeuT substrates in reconstituted systems
- Identifying the factors and affinities requires for substrate transport in the dopamine transporter
- Investigating the conformational dynamics in the serotonin transporter with fluorescence
- Purification of the human dopamine transporter
- Site-specific incorporation of fluorescent probes using cysteine chemistry and unnatural amino acids