About the Authors

Mark S. Bretscher

To whom correspondence should be addressed. E-mail: msb@mrc-lmb.cam.ac.uk

Affiliation Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom

Margaret Clotworthy

Affiliation Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: MB MC. Performed the experiments: MB MC MC. Analyzed the data: MB MC. Contributed reagents/materials/analysis tools: MB. Wrote the paper: MB MC.