1 Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada.
2 Pôle d'endocrinologie, diabète et nutrition, Institut de recherche expérimentale et clinique, Université catholique de Louvain, Brussels, Belgium.
3 Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada. Electronic address: James.D.Johnson@ubc.ca.