6njz
From Proteopedia
EphA2 LBD in complex with YSA-GSGSK-bio peptide
Structural highlights
Disease[EPHA2_HUMAN] Genetic variations in EPHA2 are the cause of susceptibility to cataract cortical age-related type 2 (ARCC2) [MIM:613020]. A developmental punctate opacity common in the cortex and present in most lenses. The cataract is white or cerulean, increases in number with age, but rarely affects vision.[1] [2] Defects in EPHA2 are the cause of cataract posterior polar type 1 (CTPP1) [MIM:116600]. A subcapsular opacity, usually disk-shaped, located at the back of the lens. It can have a marked effect on visual acuity.[3] [4] [5] [6] Note=Overexpressed in several cancer types and promotes malignancy.[7] Function[EPHA2_HUMAN] Receptor tyrosine kinase which binds promiscuously membrane-bound ephrin-A family ligands residing on adjacent cells, leading to contact-dependent bidirectional signaling into neighboring cells. The signaling pathway downstream of the receptor is referred to as forward signaling while the signaling pathway downstream of the ephrin ligand is referred to as reverse signaling. Activated by the ligand ephrin-A1/EFNA1 regulates migration, integrin-mediated adhesion, proliferation and differentiation of cells. Regulates cell adhesion and differentiation through DSG1/desmoglein-1 and inhibition of the ERK1/ERK2 (MAPK3/MAPK1, respectively) signaling pathway. May also participate in UV radiation-induced apoptosis and have a ligand-independent stimulatory effect on chemotactic cell migration. During development, may function in distinctive aspects of pattern formation and subsequently in development of several fetal tissues. Involved for instance in angiogenesis, in early hindbrain development and epithelial proliferation and branching morphogenesis during mammary gland development. Engaged by the ligand ephrin-A5/EFNA5 may regulate lens fiber cells shape and interactions and be important for lens transparency development and maintenance. With ephrin-A2/EFNA2 may play a role in bone remodeling through regulation of osteoclastogenesis and osteoblastogenesis.[8] [9] [10] [11] [12] [13] Publication Abstract from PubMedThe EPH receptor A2 (EphA2) receptor tyrosine kinase plays an important role in a plethora of biological and disease processes, ranging from angiogenesis and cancer to inflammation and parasitic infections. EphA2 is therefore considered an important drug target. Two short peptides previously identified by phage display, named YSA and SWL, are widely used as EphA2-targeting agents owing to their high specificity for this receptor. However, these peptides have only modest (micromolar) potency. Lack of structural information on the binding interactions of YSA and SWL with the extracellular EphA2 ligand-binding domain (LBD) has for many years precluded structure-guided improvements. We now report the high-resolution (1.53-2.20 A) crystal structures of the YSA peptide and several of its improved derivatives in complex with the EphA2 LBD, disclosing that YSA targets the ephrin-binding pocket of EphA2 and mimics binding features of the ephrin-A ligands. The structural information obtained enabled iterative peptide modifications conferring low nanomolar potency. Furthermore, contacts observed in the crystal structures shed light on how C-terminal features can convert YSA derivatives from antagonists to agonists that likely bivalently interact with two EphA2 molecules to promote receptor oligomerization, autophosphorylation, and downstream signaling. Consistent with this model, quantitative FRET measurements in live cells revealed that the peptide agonists promote the formation of EphA2 oligomeric assemblies. Our findings now enable rational strategies to differentially modify EphA2 signaling toward desired outcomes by using appropriately engineered peptides. Such peptides could be used as research tools to interrogate EphA2 function and develop pharmacological leads. Engineering Nanomolar Peptide LigandsThat Differentially Modulate EphA2 Receptor Signaling.,Gomez-Soler M, Petersen Gehring M, Lechtenberg BC, Zapata-Mercado E, Hristova K, Pasquale EB J Biol Chem. 2019 Apr 23. pii: RA119.008213. doi: 10.1074/jbc.RA119.008213. PMID:31015204[14] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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