PhD defence by Katrine Rude Laub
Synbio PhD-student Katrine Rude Laub from the Section of Transport Biology will defend her PhD thesis on June 26th at 10am in the festival auditorium at Frederiksberg Campus. She carried out work on the purification of a membrane transporter
Title of thesis: Purification and biochemical characterisation of the yeast ABC transporter Pdr11p
Summary: Sterols constitute an essential lipid class in eukaryotic membranes where intracellular distributions are highly regulated. In the yeast Saccharomyces cerevisiae sterol uptake has been attributed to the two plasma membrane-localised ATP-binding cassette (ABC) transporters, Aus1p and Pdr11p. These ATP-powered transporters are proposed to mediate inter- and transbilayer sterol migration, but their exact role and key features of their activity remain to be elucidated. The complexity of the native membrane hampers the study of membrane transporters at the molecular level. To achieve a detailed understanding of their action and molecular functioning, it is helpful to focus on homogeneous preparations of membrane proteins reconstituted into model membranes like detergent micelles, liposomes, and nanodiscs. In the present study, I report the first successful expression, purification, and reconstitution of the yeast ABC transporter Pdr11p. This includes optimising its overexpression utilising the galactose induction system in S. cerevisiae, screening for the best detergent to extract the protein from the membrane, and establishing purification and reconstitution protocols. By providing a purification/reconstitution protocol and adding new insight to the biochemical behaviour of Pdr11p this work paves for future studies to unravel the sterol transport mechanism.
Supervisors
Professor Thomas Günther-Pomorski, PLEN
Assessment committee
Rosa Laura Lopez Marques, Associate Professor PLEN, (Chair)
Eckhard Hofmann, Professor Ruhr University Bochum, Germany
Natalya Fedosova, Associate Professor University Aarhus, Denmark
A reception will take place after the defense at Thorvaldsensvej 40, third floor: Room R323