[1] Washington Univ, Sch Med, Dept Med, St Louis, MO 63110 USA
[2] Washington Univ, Ctr Cellular Imaging, St Louis, MO 63110 USA
[3] Washington Univ, Sch Med, Dept Cell Biol, St Louis, MO 63110 USA
[4] Washington Univ, Sch Med, Dept Physiol & Neurosci, St Louis, MO USA
[5] Washington Univ, Dept Biomed Engn, St Louis, MO 63110 USA