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Structure‐based mutagenesis of the substrate‐recognition domain of Nrdp1/FLRF identifies the binding site for the receptor tyrosine kinase ErbB3
Author(s) -
Bouyain Samuel,
Leahy Daniel J.
Publication year - 2007
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.062700307
Subject(s) - erbb3 , ubiquitin ligase , biology , microbiology and biotechnology , receptor tyrosine kinase , tyrosine kinase , erbb , neuregulin 1 , ring finger domain , ubiquitin , chemistry , biochemistry , signal transduction , transcription factor , zinc finger , gene
The E3 ubiquitin ligase neuregulin receptor degrading protein 1 (Nrdp1) mediates the ligand‐independent degradation of the epidermal growth factor receptor family member ErbB3/HER3. By regulating cellular levels of ErbB3, Nrdp1 influences ErbB3‐mediated signaling, which is essential for normal vertebrate development. Nrdp1 belongs to the tripartite or RBCC (RING, B‐box, coiled‐coil) family of ubiquitin ligases in which the RING domain is responsible for ubiquitin ligation and a variable C‐terminal region mediates substrate recognition. We report here the 1.95 Å crystal structure of the C‐terminal domain of Nrdp1 and show that this domain is sufficient to mediate ErbB3 binding. Furthermore, we have used site‐directed mutagenesis to map regions of the Nrdp1 surface that are important for interacting with ErbB3 and mediating its degradation in transfected cells. The ErbB3‐binding site localizes to a region of Nrdp1 that is conserved from invertebrates to vertebrates, in contrast to ErbB3, which is only found in vertebrates. This observation suggests that Nrdp1 uses a common binding site to recognize its targets in different species.