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Dimerization of EphA2 in Plasma Membranes
Author(s) -
Hristova Kalina,
Singh Deo,
King Christopher,
Salotto Matt,
Gupta Nisha
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.728.4
Subject(s) - eph receptor a2 , erythropoietin producing hepatocellular (eph) receptor , förster resonance energy transfer , ephrin , receptor , receptor tyrosine kinase , ligand (biochemistry) , biophysics , hek 293 cells , chemistry , microbiology and biotechnology , signal transduction , biology , biochemistry , fluorescence , physics , quantum mechanics
EphA2 is a single pass transmembrane protein and a member of the largest Receptor Tyrosine Kinase (RTK) family. EphA2 regulates cell‐cell interactions during embryonic development in humans and is known as an oncoprotein as well as a tumor suppressor. The Eph receptors differ from other RTKs since they form oligomers when they bind their ligands. However, the interactions between the Eph‐A2 receptors in the absence of ligand have not been investigated. We used spectral FRET in conjunction with two photon microscopy to probe unliganded EphA2 dimerization in HEK 293 cells. We measured the FRET efficiency with high precision over a concentration range that spans three orders of magnitude and includes the physiological range of receptor expressions. We show that EphA2 forms dimers in the absence of ligand. In addition, mutagenesis studies reveal that contacts between the EphA2 receptors that are important for ligand‐mediated clustering are also important for unliganded dimerization. We therefore propose that unliganded EphA2 dimers are an important intermediate in EphA2 signal transduction.