1. Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island 02912 1 ;
2. Beatson Institute for Cancer Research, CRC Beatson Laboratories, Bearsden, Glasgow G61 1BD, United Kingdom 2 ;
3. Department of Medicine and Whittier Diabetes Program, University of California San Diego, La Jolla, California 92093-0673 3 ; and
4. Abt. Nephrologie, Medizinische Hochschule Hannover, D-0625 Hannover, Germany4