4x6s
Grb7 SH2 domain with phosphotyrosine mimetic inhibitor peptide
Structural highlights
FunctionGRB7_HUMAN Adapter protein that interacts with the cytoplasmic domain of numerous receptor kinases and modulates down-stream signaling. Promotes activation of down-stream protein kinases, including STAT3, AKT1, MAPK1 and/or MAPK3. Promotes activation of HRAS. Plays a role in signal transduction in response to EGF. Plays a role in the regulation of cell proliferation and cell migration. Plays a role in the assembly and stability of RNA stress granules. Binds to the 5'UTR of target mRNA molecules and represses translation of target mRNA species, when not phosphorylated. Phosphorylation impairs RNA binding and promotes stress granule disassembly during recovery after cellular stress (By similarity).[1] [2] [3] [4] Publication Abstract from PubMedThe Grb7 adaptor protein is a therapeutic target for both TNBC and HER2+ breast cancer. A nonphosphorylated cyclic peptide 1 (known as G7-18NATE) inhibits Grb7 via targeting the Grb7-SH2 domain, but requires the presence of phosphate ions for both affinity and specificity. Here we report the discovery of malonate bound in the phosphotyrosine binding pocket of the apo-Grb7-SH2 structure. Based on this, we carried out the rational design and synthesis of two analogues of peptide 1 that incorporate carboxymethylphenylalanine (cmF) and carboxyphenylalanine (cF) as mimics of phosphotyrosine (pY). Binding studies using SPR confirmed that affinity for Grb7-SH2 domain is improved up to 9-fold over peptide 1 under physiological phosphate conditions (KD = 2.1-5.7 muM) and that binding is specific for Grb7-SH2 over closely related domains (low or no detectable binding to Grb2-SH2 and Grb10-SH2). X-ray crystallographic structural analysis of the analogue bearing a cmF moiety in complex with Grb7-SH2 has identified the precise contacts conferred by the pY mimic that underpin this improved molecular interaction. Together this study identifies and characterizes the tightest specific inhibitor of Grb7 to date, representing a significant development toward a new Grb7-targeted therapeutic. Cyclic Peptides Incorporating Phosphotyrosine Mimetics as Potent and Specific Inhibitors of the Grb7 Breast Cancer Target.,Watson GM, Gunzburg MJ, Ambaye ND, Lucas WA, Traore DA, Kulkarni K, Cergol KM, Payne RJ, Panjikar S, Pero SC, Perlmutter P, Wilce MC, Wilce JA J Med Chem. 2015 Oct 8;58(19):7707-18. doi: 10.1021/acs.jmedchem.5b00609. Epub, 2015 Sep 23. PMID:26359549[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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