1 Electron Microscopy Resource Center, The Rockefeller University, New York, NY, USA.
2 Robin Chemers Neustein Laboratory of Mammalian Cell Biology and Development, The Rockefeller University, New York, NY, USA.
3 Howard Hughes Medical Institute, New York, NY, USA.
4 Jill Roberts Center for Inflammatory Bowel Disease, Department of Gastroenterology and Hepatology, Weill Cornell Medicine, Cornell University, New York, NY, USA.