1. Department of Molecular Biology, Cell Biology and Biochemistry, Division of Biology and Medicine, Brown University, Providence, RI 02912, USA
2. These authors shared equally in the work
3. Present address: Department of Biological Sciences, Southern Methodist University, 6501 Airline Drive, 237-DLS, Dallas, TX 75275, USA
4. Institute for Brain and Neural Systems, Brown University, Providence, RI 02912, USA
5. Department of Physics, Brown University, Providence, RI 02912, USA