BIO-3022 Biological membranes and their proteins - 5 ECTS
Membrane proteins are responsible for most communications between cells or cellular compartments. They ensure the passage of ions, metabolites or other molecules and permit signaling. They are involved in many fundamental processes (neurotransmission, bioenergetics, cell development and many others). Their mechanisms of action rely on minute atomic properties as well as on large conformational changes occurring within their structures. However, in contrast to soluble proteins, the function of a membrane protein is also strongly dependent on the properties of the lipidic membrane in which the protein is embedded. Because of the essential roles of membrane proteins in most fundamental biological processes, they constitute major drug targets, and it is estimated that nearly 60% of the currently approved drugs target membrane proteins. The course is an introduction to biological membranes. Students will learn about the composition of these membranes, lipids and proteins, the behavior of lipids and their phase diagrams, the role of proteins and the different types of functions they achieve. The course will give a complete overview from genes (and how to recognize genes encoding membrane proteins) to the synthesis and insertion pathways of membrane proteins to their target membrane. The courses will be of general interest to biology or chemistry students, with a particular focus on membrane processes deciphered at the molecular level. The course will also bring insights into biophysics of proteins. The course is held for 2 weeks and contains 14 lectures and 5 days in the lab.
Lectures are grouped in 4 parts: 1) Lipids and Membranes (4 lectures) Lipids and Biomembranes: definition of different classes of lipids, different phases formed by lipids in water Properties of biological membranes: lipid composition and membrane proteins Examples of different membranes in eukaryotic cells (specific lipids, ratio between lipids and proteins) Lipids of organisms living under extreme conditions (low temperature, high pressure) how to maintain the fluid phase 2) Membrane proteins in vivo and main biological functions (5 lectures) Finding membrane protein encoding genes within genomes, TM predictions, Topologies of membrane proteins Synthesis and transport to membranes Main functional classes: Transporters, Receptors, Ion channels, Enzymes Protein structures and their implications in function and dynamics 3) Methods for studying membranes and membrane proteins: biochemistry, structural biology and biophysics (4 lectures) Biochemistry of membrane proteins: Solubilization, purification, crystallization Properties and role of detergents and surfactants Liposomes and functional assays Biophysical methods to study membranes Single molecule fluorescence to understand membrane proteins in cells (dynamics, segregation, oligomerization) 4) Membrane proteins and drug design (1 lecture) Which targets? Identification of new hits Strategy for rational drug design
Lab exercises will be based on AcrB a multidrug transporter from E. coli, and will comprise: 1) Membrane preparation starting from cells overexpressing AcrB 2) Solubilization of membranes, purification of AcrB with affinity columns, test of a few detergents 3) Characterization of the purified protein,SDS-Page, Western Blot, Thermal stability 4) Crystallization of AcrB 5) Reconstitution into liposomes, testing protein incorporation by sucrose gradient and identification of the fractions
The student will get
- extensive knowledge on lipids constituting biological membranes and the different phases they are able to form
- profound insight into membrane proteins: how to recognize membrane proteins from genomes and what are the expected topologies, how they are synthesized in cells, which are the main functions fulfilled by membrane proteins
- knowledge of the methods that are adapted to study membranes and membrane proteins, from biochemistry, biophysics and structural biology
- insight into the process of drug design and knows which classes of membrane proteins constitute interesting targets
- experience with the use of detergents for the solubilization of biological membranes and their purification, as well as insight into the crystallization process
- will acquired basic knowledge on the chemical nature and physical properties of lipid and detergent molecules
- can outline the main topologies encountered in structures of membrane proteins
- will know the main steps involved in membrane protein synthesis from the ribosome to protein insertion into the target membrane
- will acquire an overall overview of the main technics to study isolated membrane proteins or biological membranes
- Understands the relevance of membrane proteins in fundamental biological pathways and their implications in pathologies
- Understands the potential exploitation of membrane proteins for medical or biotechnical applications
- Knows how to read a scientific text (report, or publication) related to membrane studies
Four hours written exam approximately 2 weeks after the course.
The assessment of the final exam will be pass or fail.
Admission to the examination requires that a minimum of 80% of the theoretical and practical parts of the course has been completed and that lab work has been reported satisfactorily.
- About the course
- Campus: Tromsø |
- ECTS: 5
- Course code: BIO-3022
- Responsible unit
- Department of Arctic and Marine Biology