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A change in conformational dynamics underlies the activation of Eph receptor tyrosine kinases
Author(s) -
Wiesner Silke,
WybengaGroot Leanne E,
Warner Neil,
Lin Hong,
Pawson Tony,
FormanKay Julie D,
Sicheri Frank
Publication year - 2006
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/sj.emboj.7601315
Subject(s) - erythropoietin producing hepatocellular (eph) receptor , biology , receptor tyrosine kinase , receptor protein tyrosine kinases , conformational change , protein serine threonine kinases , kinase , tyrosine kinase , microbiology and biotechnology , protein tyrosine kinases , eph receptor a2 , dynamics (music) , ephrin , receptor , signal transduction , genetics , biophysics , protein kinase a , physics , acoustics
Eph receptor tyrosine kinases (RTKs) mediate numerous developmental processes. Their activity is regulated by auto‐phosphorylation on two tyrosines within the juxtamembrane segment (JMS) immediately N‐terminal to the kinase domain (KD). Here, we probe the molecular details of Eph kinase activation through mutational analysis, X‐ray crystallography and NMR spectroscopy on auto‐inhibited and active EphB2 and EphA4 fragments. We show that a Tyr750Ala gain‐of‐function mutation in the KD and JMS phosphorylation independently induce disorder of the JMS and its dissociation from the KD. Our X‐ray analyses demonstrate that this occurs without major conformational changes to the KD and with only partial ordering of the KD activation segment. However, conformational exchange for helix αC in the N‐terminal KD lobe and for the activation segment, coupled with increased inter‐lobe dynamics, is observed upon kinase activation in our NMR analyses. Overall, our results suggest that a change in inter‐lobe dynamics and the sampling of catalytically competent conformations for helix αC and the activation segment rather than a transition to a static active conformation underlies Eph RTK activation.