1. Howe Laboratory, Massachusetts Eye and Ear Infirmary — Harvard Medical School, 243 Charles Street, Boston, MA 02114, USA
2. Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
3. Department of Cell Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA
4. Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA