Maria Spies1, Brian O Smith2. 1. Carver College of Medicine, University of Iowa, 51 Newton Rd., 4-532 BSB, Iowa City, IA, 52242, USA. 2. Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Joseph Black Building, Glasgow, G12 8QQ, UK. Brian.Smith@glasgow.ac.uk.