Subcellular receptor redistribution and enhanced microspike formation by a Ret receptor preferentially recruiting Dok.
Ret is a receptor tyrosine kinase for the GDNF family of ligands and plays important roles during nervous system development for cell proliferation, cell migration and neurite growth. Signaling initiated from intracellular tyrosine 1062, by recruitment of several different phosphotyrosine binding (PTB) proteins (i.e. Shc, Frs2 and Dok), is important for these biological effects. By a single amino acid substitution in the PTB domain binding sequence of Ret, we have rewired the receptor such that it preferentially recruits Dok (Ret(Dok+)) with little or no remaining interactions with Shc and Frs2. Ret(Dok+) displays a sustained MAP kinase activation and a loss of Akt signaling compared to Ret(WT). We show that early events after ligand stimulation of Ret(Dok+) include massive formation of fine microspikes that are believed to be priming structures for neurite growth from the cell soma. The Ret(Dok+) receptors relocated in the membrane compartment into focal clusters at the tip of the microspikes, which was associated with Cdc42 activation. These results suggest that engagement of different adaptor proteins by Ret results in very different downstream signaling and functions within neurons and that Dok recruitment leads to a rapid receptor relocation and formation of microspikes.
Stenqvist
Anna
A
Unit of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, 171 77 Stockholm, Sweden.
Lundgren
T Kalle
TK
Smith
Matthew J
MJ
Hermanson
Ola
O
Castelo-Branco
Gonçalo
G
Pawson
Tony
T
Ernfors
Patrik
P
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D019556:COS Cells; D002454:Cell Differentiation / Q000502:physiology*; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D022081:Cell Surface Extensions / Q000378:metabolism* / Q000648:ultrastructure; D002522:Chlorocebus aethiops; D004268:DNA-Binding Proteins / Q000378:metabolism*; D051100:Glial Cell Line-Derived Neurotrophic Factor / Q000378:metabolism; D006801:Humans; D008024:Ligands; D020935:MAP Kinase Signaling System / Q000502:physiology; D009154:Mutation / Q000235:genetics; D016501:Neurites / Q000378:metabolism* / Q000648:ultrastructure; D010750:Phosphoproteins / Q000378:metabolism*; D021381:Protein Transport / Q000502:physiology; D051096:Proto-Oncogene Proteins c-ret / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D013234:Stem Cells / Q000378:metabolism* / Q000648:ultrastructure; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D004268:DNA-Binding Proteins; C489560:DOK1 protein, human; D051100:Glial Cell Line-Derived Neurotrophic Factor; D008024:Ligands; D010750:Phosphoproteins; D016601:RNA-Binding Proteins; D051096:Proto-Oncogene Proteins c-ret; D020764:cdc42 GTP-Binding Protein