1. Division of Dermatology, University of California, San Diego (UCSD), La Jolla, CA 92093, USA.
2. Department of Developmental and Cell Biology, Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, CA 92697, USA.
3. Center for Complex Biological Systems, University of California, Irvine, Irvine, CA 92697, USA.
4. Nomis Foundation Laboratories for Immunobiology and Microbial Pathogenesis, The Salk Institute for Biological Studies, San Diego, La Jolla, CA 92037, USA.