Membrane Biochemistry

Biological membranes form the barriers which separate cells from their environments, and allow compartmentalization within cells. Our main research interest is to understand how proteins and lipids interact to regulate membrane structure and function. Protein-lipid interactions are important in biological processes, such as; exocytosis, endocytosis, regulating the activity of membrane proteins, cell division, neurotransmitter release, and organelle biogenesis.

Some of our research questions are:

  • how do lipids influence structure and dynamics of membrane proteins?
  • how do lipids affect the insertion of proteins into membranes?
  • how do lipids regulate the activity of membrane proteins?
  • how do proteins affect the structure and dynamics of lipids?
  • how do peripheral membrane proteins affect the lateral distribution of lipids in the membrane?

The two current projects in the lab are:

We are trying to understand the physicochemical behavior of proteins and lipids in membranes. For example, we have found that the binding of the synaptic vesicle protein, synapsin I is modulated by the lipid packing within membranes. Cells can control the lipid packing in their membranes by metabolically altering the lipid composition and cholesterol levels. We use a variety of modern approaches that bridge biophysics, biochemistry, molecular biology and bioinformatics. Included are cloning and expression technologies that involve site-directed mutagenesis and recombinant protein purification and characterization as well as model membrane production and characterization. Biophysical techniques which are employed in our research include fluorescence spectroscopy, liposome production, isothermal titration calorimetry (ITC), atomic force microscopy (AFM), near-field microscopy and various types of chromatography. Through such studies, we are obtaining a better understanding of the physicochemical parameters that affect the interaction of proteins with membranes.


 


E-mail: jcheetha@ccs.carleton.ca