1. Henry Eyring Center for Cell and Genome Science, University of Utah, Salt Lake City, UT 84112
2. Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
3. Division of Cell Biology, Medical University of Innsbruck, Innsbruck 6020, Austria
4. School of Biological Sciences, Howard Hughes Medical Institute, University of Utah, Salt Lake City, UT 84112