Activation of the p75 neurotrophin receptor through conformational rearrangement of disulphide-linked receptor dimers.
Ligand-mediated dimerization has emerged as a universal mechanism of growth factor receptor activation. Neurotrophins interact with dimers of the p75 neurotrophin receptor (p75(NTR)), but the mechanism of receptor activation has remained elusive. Here, we show that p75(NTR) forms disulphide-linked dimers independently of neurotrophin binding through the highly conserved Cys(257) in its transmembrane domain. Mutation of Cys(257) abolished neurotrophin-dependent receptor activity but did not affect downstream signaling by the p75(NTR)/NgR/Lingo-1 complex in response to MAG, indicating the existence of distinct, ligand-specific activation mechanisms for p75(NTR). FRET experiments revealed a close association of p75(NTR) intracellular domains that was transiently disrupted by conformational changes induced upon NGF binding. Although mutation of Cys(257) did not alter the oligomeric state of p75(NTR), the mutant receptor was no longer able to propagate conformational changes to the cytoplasmic domain upon ligand binding. We propose that neurotrophins activate p75(NTR) by a mechanism involving rearrangement of disulphide-linked receptor subunits.
Division of Molecular Neurobiology, Department of Neuroscience, Karolinska Institute, 17177 Stockholm, Sweden.
Marçal
M
Vilar
Ioannis
I
Charalampopoulos
Rajappa S
RS
Kenchappa
Anastasia
A
Simi
Esra
E
Karaca
Alessandra
A
Reversi
Soyoung
S
Choi
Mark
M
Bothwell
Ismael
I
Mingarro
Wilma J
WJ
Friedman
Giampietro
G
Schiavo
Philippe I H
PI
Bastiaens
Peter J
PJ
Verveer
Bruce D
BD
Carter
Carlos F
CF
Ibáñez
D000818:Animals; D000831:Animals, Newborn; D001665:Binding Sites / Q000235:genetics; D016923:Cell Death / Q000187:drug effects / Q000235:genetics; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D003545:Cysteine / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics; D051379:Mice; D009154:Mutation / Q000235:genetics; D016328:NF-kappa B / Q000378:metabolism; D020932:Nerve Growth Factor / Q000494:pharmacology; D009419:Nerve Tissue Proteins / Q000235:genetics; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D009842:Oligopeptides / Q000235:genetics; D011485:Protein Binding / Q000235:genetics; D011487:Protein Conformation; D055503:Protein Multimerization / Q000235:genetics / Q000502:physiology*; D034741:RNA, Small Interfering / Q000378:metabolism; D051381:Rats; D020800:Receptor, Nerve Growth Factor / Q000235:genetics / Q000378:metabolism*; D017978:Receptors, Growth Factor; D017475:Receptors, Nerve Growth Factor / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D017783:Superior Cervical Ganglion / Q000166:cytology; D014162:Transfection / Q000379:methods; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
C525164:LINGO1 protein, rat; D008565:Membrane Proteins; D016328:NF-kappa B; C526428:NGR peptide; D009419:Nerve Tissue Proteins; D009842:Oligopeptides; D034741:RNA, Small Interfering; D020800:Receptor, Nerve Growth Factor; D017978:Receptors, Growth Factor; D017475:Receptors, Nerve Growth Factor; C485184:enhanced green fluorescent protein; C068313:Ngfr protein, rat; D049452:Green Fluorescent Proteins; D020932:Nerve Growth Factor; D020742:rhoA GTP-Binding Protein; D003545:Cysteine