1. Departments of Cell Biology and Medicine, Baylor College of Medicine, Houston, TX 77030.
2. Department of Pharmacology, Southwestern Graduate School, University of Texas Southwestern Medical Center, Dallas, TX 75235.
3. Department of Physiology and Molecular Biophysics, Baylor College of Medicine, Houston, TX 77030.
4. Department of Cell Biology, Baylor College of Medicine, Houston, TX 77030.
5. Department of Molecular Biophysics, Baylor College of Medicine, Houston, TX 77030.