Structural Basis for the Interaction between the Growth Factor-binding Protein GRB10 and the E3 Ubiquitin Ligase NEDD4

Abstract

In addition to inhibiting insulin receptor and IGF1R kinase activity by directly binding to the receptors, GRB10 can also negatively regulate insulin and IGF1 signaling by mediating insulin receptor and IGF1R degradation through ubiquitination. It has been shown that GRB10 can interact with the C2 domain of the E3 ubiquitin ligase NEDD4 through its Src homology 2 (SH2) domain. Therefore, GRB10 might act as a connector, bringing NEDD4 close to IGF1R to facilitate the ubiquitination of IGF1R by NEDD4. This is the first case in which it has been found that an SH2 domain could colocalize a ubiquitin ligase and its substrate. Here we report the crystal structure of the NEDD4 C2-GRB10 SH2 complex at 2.0 Å . The structure shows that there are three interaction interfaces between NEDD4 C2 and GRB10 SH2. The main interface centers on an antiparallel ␤-sheet composed of the F ␤-strand of GRB10 SH2 and the C ␤-strand of NEDD4 C2. NEDD4 C2 binds at nonclassical sites on the SH2 domain surface, far from the classical phosphotyrosine-binding pocket. Hence, this interaction is phosphotyrosine-independent, and GRB10 SH2 can bind the C2 domain of NEDD4 and the kinase domain of IGF1R simultaneously. Based on these results, a model of how NEDD4 interacts with IGF1R through GRB10 has been proposed. This report provides further evidence that SH2 domains can participate in important signaling interactions beyond the classical recognition of phosphotyrosine.The GRB7 (growth factor receptor-binding protein) family of adaptor proteins includes GRB7, GRB10, and GRB14. These proteins share a conserved molecular architecture: a proline-rich N-terminal region, a Ras-associating-like domain, a pleckstrin homology domain, a family-specific BPS region, and a conserved C-terminal Src homology 2 (SH2) 2 domain (1, 2). Their SH2 domains have the ability to recognize phosphotyrosine-containing peptides on a variety of activated tyrosine kinase receptors. GRB7 has been shown to interact with EGF receptor, ErB2 receptor, EphB1, focal adhesion kinase, and platelet-derived growth factor receptor and to be involved in regulating cell migration (3, 4). GRB10 and GRB14 have been shown to interact with insulin receptor (IR), IGF1R (insulin-like growth factor 1 receptor), EGF receptor, Raf1 kinase, and MEK1 kinase and to be involved in cell growth regulation (5-11). The Grb10 gene is maternally imprinted in mice. When the Grb10 gene was disrupted by a gene trap insertion, the mutant mice were ϳ30% greater in size than normal, with disproportionately large livers (5, 12). As adults, these mutant mice had improved glucose tolerance, increased muscle mass, and reduced adiposity (13, 14). Furthermore, Grb10 transgenic mice overexpressing GRB10 showed growth retardation and insulin resistance (15). These results indicate that GRB10 plays a negative role in cell growth, as a consequence of hypernegative regulation of the IR and IGF1R. Mice lacking the Grb14 gene were of normal size and had improved glucose tolerance and increased insulin signaling in muscle and ...

Cellular and molecular interactions of phosphoinositides and peripheral proteins

“…In most cell types PI(3,4,5)P 3 levels increase in the PS rich inner leaflet of the PM in response to various growth inducing stimuli, and thus Akt1 is recruited under specific temporal conditions (Huang et al 2011). Coincidence detection of lipid and proteins also seems to be an important regulatory mechanism of PDZ (Chen et al 2012; Wawrzyniak et al 2013) and some C2 domains (Huang and Szebenyi 2010; Tian et al 2011). …”

Endocytosis of Receptor Tyrosine Kinases

“…2) (Vecchione et al 2003;Monami et al 2008). The SH2 domain of Grb10 is capable of simultaneous binding to the C2 domain of NEDD4-1 and IGF-1R (Huang and Szebenyi 2010). Expression of Grb10 and NEDD4-1 mutants significantly reduced endocytosis of IGF-1R (Vecchione et al 2003;Monami et al 2008).…”

Suppression of Feedback Loops Mediated by PI3K/mTOR Induces Multiple Overactivation of Compensatory Pathways: An Unintended Consequence Leading to Drug Resistance

“…Grb10 is known to suppress signaling induced by insulin and IGFs (37) and mice lacking Grb10 are larger than normal and exhibit enhanced insulin sensitivity (38). In addition to inhibiting insulin/IGF1 receptor tyrosine kinase activity by direct binding, Grb10 also mediates degradation of these receptors through ubiquitination (39). The phosphorylation of Grb10 by mTORC1 enhances its stability and capacity to inhibit insulin/IGF signaling.…”