1. Department of Biological Chemistry, University of California, Los Angeles, CA 90095, USA.
2. Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, CA 90095, USA.
3. Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA.
4. Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA.
5. Department of Pathology and Laboratory Medicine, University of California, Los Angeles, CA 90095, USA.