The winning image of this month's Nature Cell Biology and Nature Reviews Molecular Cell Biology 'Cell of the Month' competition was submitted by Cécile Chalouni (Ludwig Cancer Research Institute, Yale University School of Medicine, USA (cecile.chalouni@yale.edu)). It shows the results of an immunohistochemical study of the human colon.

A frozen human colon tissue section was stained for actin (green) and the epithelial marker A33 (red). Nuclei were stained blue. The image was obtained using a Zeiss LSM 510 confocal microscope (×40 objective). Bar, 25 μm.

The winner would like to thank Derek Toomre and Ira Mellman (both at the Ludwig Cancer Research Institute, Yale University School of Medicine, USA) for support and advice.