Receptor tyrosine kinase activity is known to occur in the absence of extracellular stimuli. Importantly, this "background" level of receptor phosphorylation is insufficient to effect a downstream response, suggesting that strict controls are present and prohibit full activation. Here a mechanism is described in which control of FGFR2 activation is provided by the adaptor protein Grb2. Dimeric Grb2 binds to the C termini of two FGFR2 molecules. This heterotetramer is capable of a low-level receptor transphosphorylation, but C-terminal phosphorylation and recruitment of signaling proteins are sterically hindered. Upon stimulation, FGFR2 phosphorylates tyrosine residues on Grb2, promoting dissociation from the receptor and allowing full activation of downstream signaling. These observations establish a role for Grb2 as an active regulator of RTK signaling.
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http://dx.doi.org/10.1016/j.cell.2012.04.033 | DOI Listing |
Chem Sci
September 2024
Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University 1-1 Minamiosawa Hachioji Tokyo 192-0397 Japan
The adaptor protein human GRB2 plays crucial roles in mediating signal transduction from cell membrane receptors to RAS and its downstream proteins by recruiting SOS1. Recent studies have revealed that GRB2 also serves as a scaffold for liquid-liquid phase separation (LLPS) with SOS1 and transmembrane receptors, which is thought to regulate the magnitude of cell signalling pathways. In this study, we employed solution NMR spectroscopy to investigate the interactions of the full-length GRB2 with proline-rich motifs (PRMs) derived from ten potential GRB2-binding sites in SOS1, as well as a peptide from a phosphorylation site of EGFR.
View Article and Find Full Text PDFInt J Biol Macromol
November 2024
Department of Physics, São Paulo State University (UNESP), Institute of Biosciences, Humanities and Exact Sciences, Sao Jose do Rio Preto, 15054-000, SP, Brazil; Multiuser Center for Biomolecular Innovation (CMIB), São Paulo State University (UNESP), Institute of Biosciences, Humanities and Exact Sciences, Sao Jose do Rio Preto, 15054-000, SP, Brazil. Electronic address:
The Growth factor receptor-bound protein 2 (Grb2) participates in early signaling complexes and regulates tyrosine kinase-mediated signal transduction through a monomer-dimer equilibrium. Grb2 dimeric state inhibits signal transduction whereas the monomer promotes signaling downstream. Since Grb2 dimer K is ∼0.
View Article and Find Full Text PDFJ Biol Chem
August 2024
National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic; Central European Institute of Technology, Masaryk University, Brno, Czech Republic. Electronic address:
Isoforms of microtubule-associated protein 2 (MAP2) differ from their homolog Tau in the sequence and interactions of the N-terminal region. Binding of the N-terminal region of MAP2c (N-MAP2c) to the dimerization/docking domains of the regulatory subunit RIIα of cAMP-dependent protein kinase (RIIDD) and to the Src-homology domain 2 (SH2) of growth factor receptor-bound protein 2 (Grb2) have been described long time ago. However, the structural features of the complexes remained unknown due to the disordered nature of MAP2.
View Article and Find Full Text PDFExp Ther Med
January 2024
Department of Pharmacology, Gifu University Graduate School of Medicine, Gifu 501-1194, Japan.
Bone remodeling is tightly controlled by various factors, including hormones, autacoids and cytokines. Among them, oncostatin M (OSM) is a multifunctional cytokine produced by osteal macrophages, which serves as an essential modulator of bone remodeling. Macrophage colony-stimulating factor (M-CSF) and osteoprotegerin are secreted by osteoblasts, and also have pivotal roles in the regulation of the bone remodeling process.
View Article and Find Full Text PDFNat Commun
June 2023
The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, 3052, Australia.
PEAK pseudokinases regulate cell migration, invasion and proliferation by recruiting key signaling proteins to the cytoskeleton. Despite lacking catalytic activity, alteration in their expression level is associated with several aggressive cancers. Here, we elucidate the molecular details of key PEAK signaling interactions with the adapter proteins CrkII and Grb2 and the scaffold protein 14-3-3.
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