[1] Queens Univ, Dept Biochem, Kingston, ON K7L 3N6, Canada
[2] Stanford Univ, Dept Mol & Cellular Physiol, Stanford, CA 94305 USA
[3] Weizmann Inst Sci, Dept Biol Chem, IL-76100 Rehovot, Israel
[4] Queens Univ, Prot Funct Discovery Grp, Kingston, ON K7L 3N6, Canada