3mx0
From Proteopedia
Crystal Structure of EphA2 ectodomain in complex with ephrin-A5
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] [EFNA5_HUMAN] Cell surface GPI-bound ligand for Eph receptors, a family of receptor tyrosine kinases which are crucial for migration, repulsion and adhesion during neuronal, vascular and epithelial development. Binds promiscuously Eph receptors 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. Induces compartmentalized signaling within a caveolae-like membrane microdomain when bound to the extracellular domain of its cognate receptor. This signaling event requires the activity of the Fyn tyrosine kinase. Activates the EPHA3 receptor to regulate cell-cell adhesion and cytoskeletal organization. With the receptor EPHA2 may regulate lens fiber cells shape and interactions and be important for lens transparency maintenance. May function actively to stimulate axon fasciculation. The interaction of EFNA5 with EPHA5 also mediates communication between pancreatic islet cells to regulate glucose-stimulated insulin secretion. Cognate/functional ligand for EPHA7, their interaction regulates brain development modulating cell-cell adhesion and repulsion.[14] [15] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedEph receptor tyrosine kinases and their ephrin ligands regulate cell navigation during normal and oncogenic development. Signaling of Ephs is initiated in a multistep process leading to the assembly of higher-order signaling clusters that set off bidirectional signaling in interacting cells. However, the structural and mechanistic details of this assembly remained undefined. Here we present high-resolution structures of the complete EphA2 ectodomain and complexes with ephrin-A1 and A5 as the base unit of an Eph cluster. The structures reveal an elongated architecture with novel Eph/Eph interactions, both within and outside of the Eph ligand-binding domain, that suggest the molecular mechanism underlying Eph/ephrin clustering. Structure-function analysis, by using site-directed mutagenesis and cell-based signaling assays, confirms the importance of the identified oligomerization interfaces for Eph clustering. Architecture of Eph receptor clusters.,Himanen JP, Yermekbayeva L, Janes PW, Walker JR, Xu K, Atapattu L, Rajashankar KR, Mensinga A, Lackmann M, Nikolov DB, Dhe-Paganon S Proc Natl Acad Sci U S A. 2010 May 26. PMID:20505120[16] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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Categories: Human | Receptor protein-tyrosine kinase | Atapattu, L | Dhe-Paganon, S | Himanen, J P | Janes, P W | Lackmann, M | Mensinga, A | Nikolov, D B | Rajashankar, K R | Walker, J R | Xu, K | Yermekbayeva, L | Ectodomain | Receptor-ligand complex | Receptor-receptor interaction | Transferase receptor-signalling protein complex
