Ras-Related Associated with Diabetes
Ras associated with diabetes (Rad) was identified in the beginning of the 1990s as a clone differentially expressed in two subtraction cDNA libraries prepared from skeletal muscle of normal individuals and patients with Type II (non-insulin-dependent) diabetes mellitus (Reynet and Kahn 1993). Analysis of the newly identified clone revealed about 50% identity at the nucleotide level with members of the Ras superfamily, which consists of more than a hundred low-molecular-weight guanine nucleotide–binding proteins, also referred to as small GTPases. The major feature of this class of molecules is their ability to cycle between a GDP-bound inactive and a GTP-bound active conformation. Small GTPases are divided into six subfamilies: Ras, Rho, Arf, Rab, Ran, and RGK, in which Rad is included. They participate in important cellular processes such as growth and differentiation, cytoskeletal dynamics, membrane...