[1] Univ Alabama Birmingham, Dept Neurobiol, Birmingham, AL 35294 USA
[2] Univ Alabama Birmingham, Dept Cell Biol, Birmingham, AL 35294 USA
[3] Univ Calif Berkeley, Dept Cell & Mol Biol, Berkeley, CA 94720 USA
[4] Univ Cambridge, Mol Signalling Lab, Babraham Inst, Dept Zool, Cambridge CB2 3ES, England
[5] SUNY Stony Brook, Dept Chem, Stony Brook, NY 11794 USA
[6] Univ Utah, Dept Med Chem, Salt Lake City, UT 84112 USA