Synthetic peptides define critical contacts between elongin C, elongin B, and the von Hippel-Lindau protein

The von Hippel-Lindau tumor suppressor protein (pVHL) negatively regulates hypoxia-inducible mRNAs such as the mRNA encoding vascular endothelial grow th factor (VEGF). This activity has been linked to its ability to form mult imeric complexes that contain elongin C, elongin B, and Cul2. To understand this process in greater detail, we performed a series of in vitro binding assays using pVHL, elongin B, and elongin C variants as well as synthetic p eptide competitors derived from pVHL or elongin C. A subdomain of elongin C (residues 17-50) was necessary and sufficient for detectable binding to el ongin B. In contrast, elongin B residues required for binding to elongin C were not confined to a discrete colinear domain. We found that the pVHL (re sidues 157-171) is necessary and sufficient for binding to elongin C in vit ro and is frequently mutated in families with VHL disease. These mutations preferentially involve residues that directly bind to elongin C and/or alte r the conformation of pVHL such that binding to elongin C is at least parti ally diminished. These results are consistent with the view that diminished binding of pVHL to the elongins plays a causal role in VHL disease.