Eukaryotic cells contain a number of vaguely defined supramolecular structures--aptly termed dots, speckles, and bodies--whose functional roles are unclear. The individual proteins found within these structures perform diverse functions, but many possess a small zinc-binding motif called a RING domain. Kentsis et al. report that purified RING domains from several unrelated proteins, including the breast cancer susceptibility gene product 1 (BRCA1) and the promyelocytic leukemia protein (PML), can self-assemble in vitro into high-order structures that resemble those formed in cells. These RING bodies acted as structural scaffolds for multiple partner proteins, raising the possibility that the function of RING domain self-assembly in cells is to integrate biochemical reactions. -- PAK
Proc. Natl. Acad. Sci. U.S.A. 99, 15404 (2002).