1. Department of Biochemistry and Structural Biology, Joan and Sanford I. Weill Graduate School of Medical Sciences, Cornell University, New York, NY 10021, USA.
2. Dana-Farber Cancer Institute and Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA.
3. Cellular Biochemistry and Biophysics Program and Howard Hughes Medical Institute, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.