PAMELA BJ&OUML;RKMAN TO GIVE BLOCH LECTURE
May 26th, 2005
The Björkman laboratory continues to study the structural biology of cell surface recognition and is particularly interested in the structure and function of structural homologs of class I MHC molecules. For example, crystal structures elucidated how the neonatal Fc receptor uses its class I-like fold to bind IgG molecules. The Fc receptor causes the transfer of maternal IgG molecules to the fetus to transfer immunity to the neonate. Another class I-like molecule of interest in the Björkman lab is HFE, which is defective in human hereditary hemochromatosis, an iron metabolism disease causing iron overload. Björkman studies the interactions of HFE with the transferrin receptor, and how it affects binding of transferrin and iron uptake by cells. Yet another example of a class I-like molecule is the Zn-α2-glycoprotein (ZAG), which has been implicated in cachexia, a wasting syndrome affecting terminally ill patients. Structures determined in the Björkman lab showed how ZAG binds non-peptide ligands in its hydrophobic groove.
A recurring theme in Björkman’s research is therefore the class I MHC fold, and her work has highlighted the diversity of functions performed by these class I-like molecules. However, as a true structural biologist, the static pictures provided by x-ray crystallography are often only the beginning of Björkman’s studies. The crystal structures are followed by biochemical and biophysical analyses of the proteins and their interactions with biological ligands. More recently, Björkman’s research is moving to a larger scale, using electron microscopy and confocal imaging of HFE and the Fc receptor at work inside cells. The combination of molecular and cell-based techniques will likely yield many more insights into the biological mechanisms of these proteins.