9c66
Structure of the Mena EVH1 domain bound to the polyproline segment of PTP1B
Structural highlights
FunctionENAH_HUMAN Ena/VASP proteins are actin-associated proteins involved in a range of processes dependent on cytoskeleton remodeling and cell polarity such as axon guidance and lamellipodial and filopodial dynamics in migrating cells. ENAH induces the formation of F-actin rich outgrowths in fibroblasts. Acts synergistically with BAIAP2-alpha and downstream of NTN1 to promote filipodia formation (By similarity).[1] [2] Publication Abstract from PubMedThe Enabled/VASP homology 1 (EVH1) domain is a small module that interacts with proline-rich stretches in its ligands and is found in various signaling and scaffolding proteins. Mena, the mammalian homologue of Ena, is involved in diverse actin-associated events, such as membrane dynamics, bacterial motility, and tumor intravasation and extravasation. Two-dimensional (2D) (1)H-(15)N HSQC NMR was used to study Mena EVH1 binding properties, defining the amino acids involved in ligand recognition for the physiological ligands ActA and PCARE, and a synthetic polyproline-inspired small molecule (hereafter inhibitor 6c). Chemical shift perturbations indicated that proline-rich segments bind in the conserved EVH1 hydrophobic cleft. The PCARE-derived peptide elicited more perturbations compared to the ActA-derived peptide, consistent with a previous report of a structural alteration in the solvent-exposed beta7-beta8 loop. Unexpectedly, EVH1 and the proline-rich segment of PTP1B did not exhibit NMR chemical shift perturbations; however, the high-resolution crystal structure implicated the conserved EVH1 hydrophobic cleft in ligand recognition. Intrinsic steady-state fluorescence and fluorescence polarization assays indicate that residues outside the proline-rich segment enhance the ligand affinity for EVH1 (K(d) = 3-8 muM). Inhibitor 6c displayed tighter binding (K(d) approximately 0.3 muM) and occupies the same EVH1 cleft as physiological ligands. These studies revealed that the EVH1 domain enhances ligand affinity through recognition of residues flanking the proline-rich segments. Additionally, a synthetic inhibitor binds more tightly to the EVH1 domain than natural ligands, occupying the same hydrophobic cleft. Insights into the Interaction Landscape of the EVH1 Domain of Mena.,LaComb L, Ghosh A, Bonanno JB, Nilson DJ, Poppel AJ, Dada L, Cahill SM, Maianti JP, Kitamura S, Cowburn D, Almo SC Biochemistry. 2024 Aug 13. doi: 10.1021/acs.biochem.4c00331. PMID:39138154[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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