Ephrin type-A receptor 4 - P54764 (EPHA4_HUMAN)

 

Protein Feature View of PDB entries mapped to a UniProtKB sequence  

  • Number of PDB entries for P54764: 15
 
Function
Receptor tyrosine kinase which binds membrane-bound ephrin 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. Highly promiscuous, it has the unique property among Eph receptors to bind and to be physiologically activated by both GPI-anchored ephrin-A and transmembrane ephrin-B ligands including EFNA1 and EFNB3. Upon activation by ephrin ligands, modulates cell morphology and integrin-dependent cell adhesion through regulation of the Rac, Rap and Rho GTPases activity. Plays an important role in the development of the nervous system controlling different steps of axonal guidance including the establishment of the corticospinal projections. May also control the segregation of motor and sensory axons during neuromuscular circuit development. In addition to its role in axonal guidance plays a role in synaptic plasticity. Activated by EFNA1 phosphorylates CDK5 at 'Tyr-15' which in turn phosphorylates NGEF regulating RHOA and dendritic spine morphogenesis. In the nervous system, plays also a role in repair after injury preventing axonal regeneration and in angiogenesis playing a role in central nervous system vascular formation. Additionally, its promiscuity makes it available to participate in a variety of cell-cell signaling regulating for instance the development of the thymic epithelium. UniProt
Catalytic Activity
ATP + a [protein]-L-tyrosine = ADP + a [protein]-L-tyrosine phosphate. UniProt
Pathway Maps
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Subunit Structure
Heterotetramer upon binding of the ligand. The heterotetramer is composed of an ephrin dimer and a receptor dimer. Oligomerization is probably required to induce biological responses. Interacts (phosphorylated at position Tyr-602) with FYN. Interacts with CDK5, CDK5R1 and NGEF; upon activation by EFNA1 induces NGEF phosphorylation by the kinase CDK5. Interacts with CHN1; effector of EPHA4 in axon guidance linking EPHA4 activation to RAC1 regulation (By similarity). Interacts (via PDZ motif) with SIPA1L1 (via PDZ domain); controls neuronal morphology through regulation of the RAP1 (RAP1A or RAP1B) and RAP2 (RAP2A, RAP2B or RAP2C) GTPases. UniProt
Domain
The protein kinase domain mediates interaction with NGEF. UniProt
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Data in green originates from UniProtKB  
Variation data (sourced from UniProt) shows non-genetic variation from the ExPASy   and dbSNP   websites.
Data in yellow originates from Pfam  , by interacting with the HMMER3 web site  
Data in purple originates from Phosphosite  .
Data in orange originates from the SCOP   (version 1.75) and SCOPe   (version 2.04) classifications.
Data in grey has been calculated using BioJava  . Protein disorder predictions are based on JRONN (Troshin, P. and Barton, G. J. unpublished), a Java implementation of RONN  
  • Red: potentially disorderd region
  • Blue: probably ordered region.
Hydropathy has been calculated using a sliding window of 15 residues and summing up scores from standard hydrophobicity tables.
  • Red: hydrophobic
  • Blue: hydrophilic.
Data in lilac represent the genomic exon structure projected onto the UniProt sequence.
Data in blue originates from PDB
  • Secstruc: Secondary structure projected from representative PDB entries onto the UniProt sequence.
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Validation Track

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Data in red indicates combined ranges of Homology Models from SBKB   and the Protein Model Portal  
The PDB to UniProt mapping is based on the data provided by the EBI SIFTS project. See also Velankar et al., Nucleic Acids Research 33, D262-265 (2005).
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