1. The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
2. Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development (NICHD), Bethesda, MD 20892, USA
3. National High Magnetic Field Laboratory and Department of Biological Science, The Florida State University, Tallahassee, FL 32310, USA