Scaffold proteins are hubs for the coordination of intracellular signaling networks. The scaffold protein CNK1 promotes several signal transduction pathway. Here we demonstrate that sterile motif alpha (SAM) domain-dependent oligomerization of CNK1 stimulates CNK1-mediated signaling in growth factor-stimulated cells. We identified Ser22 located within the SAM domain as AKT-dependent phosphorylation site triggering CNK1 oligomerization. Oligomeric CNK1 increased the affinity for active AKT indicating a positive AKT feedback mechanism. A CNK1 mutant lacking the SAM domain and the phosphorylation-defective mutant CNK1(S22A) antagonizes oligomerization and prevents CNK1-driven cell proliferation and matrix metalloproteinase 14 promoter activation. The phosphomimetic mutant CNK1(S22D) constitutively oligomerizes and stimulates CNK1 downstream signaling. Searching the COSMIC database revealed Ser22 as putative target for oncogenic activation of CNK1. Like the phosphomimetic mutant CNK1(S22D), the oncogenic mutant CNK1(S22F) forms clusters in serum-starved cells comparable to clusters of CNK1 in growth factor-stimulated cells. CNK1 clusters induced by activating Ser22 mutants correlate with enhanced cell invasion and binding to and activation of ADP ribosylation factor 1 associated with tumor formation. Mutational analysis indicate that EGF-triggered phosphorylation of Thr8 within the SAM domain prevents AKT binding and antagonizes CNK1-mediated AKT signaling. Our findings reveal SAM domain-dependent oligomerization by AKT as switch for CNK1 activation.
%0 Journal Article
%1 fischerAKTdependentPhosphorylationSAM2017
%A Fischer, Adrian
%A Weber, Wilfried
%A Warscheid, Bettina
%A Radziwill, Gerald
%C Netherlands
%D 2017
%J Biochimica et biophysica acta. Molecular cell research
%K *Feedback 14/genetics/metabolism,Molecular Adhesion,Cell Alpha Cells,HeLa Cells,Humans,Intracellular Expression Genetic,HEK293 Genetic,Protein Metalloproteinase Mimicry,Mutation,Oligomerization,Oncogene,Phosphorylation,Promoter Motif,Cell Movement,Cell Multimerization,Proto-Oncogene Neoplastic,*Sterile Peptides Physiological,*Gene Proliferation,Databases Proteins Proteins/*genetics/metabolism,Matrix Regions Regulation Signaling Transduction,Signaling,to_read and c-akt/*genetics/metabolism,Scaffold protein,Signal
%N 1
%P 89--100
%R 10.1016/j.bbamcr.2016.10.009
%T AKT-dependent Phosphorylation of the SAM Domain Induces Oligomerization and Activation of the Scaffold Protein CNK1.
%V 1864
%X Scaffold proteins are hubs for the coordination of intracellular signaling networks. The scaffold protein CNK1 promotes several signal transduction pathway. Here we demonstrate that sterile motif alpha (SAM) domain-dependent oligomerization of CNK1 stimulates CNK1-mediated signaling in growth factor-stimulated cells. We identified Ser22 located within the SAM domain as AKT-dependent phosphorylation site triggering CNK1 oligomerization. Oligomeric CNK1 increased the affinity for active AKT indicating a positive AKT feedback mechanism. A CNK1 mutant lacking the SAM domain and the phosphorylation-defective mutant CNK1(S22A) antagonizes oligomerization and prevents CNK1-driven cell proliferation and matrix metalloproteinase 14 promoter activation. The phosphomimetic mutant CNK1(S22D) constitutively oligomerizes and stimulates CNK1 downstream signaling. Searching the COSMIC database revealed Ser22 as putative target for oncogenic activation of CNK1. Like the phosphomimetic mutant CNK1(S22D), the oncogenic mutant CNK1(S22F) forms clusters in serum-starved cells comparable to clusters of CNK1 in growth factor-stimulated cells. CNK1 clusters induced by activating Ser22 mutants correlate with enhanced cell invasion and binding to and activation of ADP ribosylation factor 1 associated with tumor formation. Mutational analysis indicate that EGF-triggered phosphorylation of Thr8 within the SAM domain prevents AKT binding and antagonizes CNK1-mediated AKT signaling. Our findings reveal SAM domain-dependent oligomerization by AKT as switch for CNK1 activation.
@article{fischerAKTdependentPhosphorylationSAM2017,
abstract = {Scaffold proteins are hubs for the coordination of intracellular signaling networks. The scaffold protein CNK1 promotes several signal transduction pathway. Here we demonstrate that sterile motif alpha (SAM) domain-dependent oligomerization of CNK1 stimulates CNK1-mediated signaling in growth factor-stimulated cells. We identified Ser22 located within the SAM domain as AKT-dependent phosphorylation site triggering CNK1 oligomerization. Oligomeric CNK1 increased the affinity for active AKT indicating a positive AKT feedback mechanism. A CNK1 mutant lacking the SAM domain and the phosphorylation-defective mutant CNK1(S22A) antagonizes oligomerization and prevents CNK1-driven cell proliferation and matrix metalloproteinase 14 promoter activation. The phosphomimetic mutant CNK1(S22D) constitutively oligomerizes and stimulates CNK1 downstream signaling. Searching the COSMIC database revealed Ser22 as putative target for oncogenic activation of CNK1. Like the phosphomimetic mutant CNK1(S22D), the oncogenic mutant CNK1(S22F) forms clusters in serum-starved cells comparable to clusters of CNK1 in growth factor-stimulated cells. CNK1 clusters induced by activating Ser22 mutants correlate with enhanced cell invasion and binding to and activation of ADP ribosylation factor 1 associated with tumor formation. Mutational analysis indicate that EGF-triggered phosphorylation of Thr8 within the SAM domain prevents AKT binding and antagonizes CNK1-mediated AKT signaling. Our findings reveal SAM domain-dependent oligomerization by AKT as switch for CNK1 activation.},
added-at = {2024-05-17T13:01:35.000+0200},
address = {Netherlands},
author = {Fischer, Adrian and Weber, Wilfried and Warscheid, Bettina and Radziwill, Gerald},
biburl = {https://www.bibsonomy.org/bibtex/2732da1248182236ca378697c8cc4835b/warscheidlab},
copyright = {Copyright {\^A}{\copyright} 2016 Elsevier B.V. All rights reserved.},
doi = {10.1016/j.bbamcr.2016.10.009},
interhash = {b1bad659801c80feaee8302dc2a8f367},
intrahash = {732da1248182236ca378697c8cc4835b},
issn = {0167-4889},
journal = {Biochimica et biophysica acta. Molecular cell research},
keywords = {*Feedback 14/genetics/metabolism,Molecular Adhesion,Cell Alpha Cells,HeLa Cells,Humans,Intracellular Expression Genetic,HEK293 Genetic,Protein Metalloproteinase Mimicry,Mutation,Oligomerization,Oncogene,Phosphorylation,Promoter Motif,Cell Movement,Cell Multimerization,Proto-Oncogene Neoplastic,*Sterile Peptides Physiological,*Gene Proliferation,Databases Proteins Proteins/*genetics/metabolism,Matrix Regions Regulation Signaling Transduction,Signaling,to_read and c-akt/*genetics/metabolism,Scaffold protein,Signal},
langid = {english},
month = jan,
number = 1,
pages = {89--100},
pmid = {27769899},
timestamp = {2024-05-17T13:01:35.000+0200},
title = {{{AKT-dependent}} Phosphorylation of the {{SAM}} Domain Induces Oligomerization and Activation of the Scaffold Protein {{CNK1}}.},
volume = 1864,
year = 2017
}