Nuclear HuR accumulation through phosphorylation by Cdk1.
A predominantly nuclear RNA-binding protein, HuR translocates to the cytoplasm in response to stress and proliferative signals, where it stabilizes or modulates the translation of target mRNAs. Here, we present evidence that HuR phosphorylation at S202 by the G2-phase kinase Cdk1 influences its subcellular distribution. HuR was specifically phosphorylated in synchronous G2-phase cultures; its cytoplasmic levels increased by Cdk1-inhibitory interventions and declined in response to Cdk1-activating interventions. In keeping with the prominently cytoplasmic location of the nonphosphorylatable point mutant HuR(S202A), phospho-HuR(S202) was shown to be predominantly nuclear using a novel anti-phospho-HuR(S202) antibody. The enhanced cytoplasmic presence of unphosphorylated HuR was linked to its decreased association with 14-3-3 and to its heightened binding to target mRNAs. Our findings suggest that Cdk1 phosphorylates HuR during G2, thereby helping to retain it in the nucleus in association with 14-3-3 and hindering its post-transcriptional function and anti-apoptotic influence.
Kim
Hyeon Ho
HH
Laboratory of Cellular and Molecular Biology, National Institute on Aging-Intramural Research Program, National Institutes of Health, Baltimore, Maryland 21224, USA.
Abdelmohsen
Kotb
K
Lal
Ashish
A
Pullmann
Rudolf
R
Yang
Xiaoling
X
Galban
Stefanie
S
Srikantan
Subramanya
S
Martindale
Jennifer L
JL
Blethrow
Justin
J
Shokat
Kevan M
KM
Gorospe
Myriam
M
D048948:14-3-3 Proteins / Q000378:metabolism; D021581:Active Transport, Cell Nucleus; D000954:Antigens, Surface / Q000378:metabolism*; D016203:CDC2 Protein Kinase / Q000378:metabolism*; D002453:Cell Cycle / Q000502:physiology; D002467:Cell Nucleus / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; D006367:HeLa Cells; D006801:Humans; D010766:Phosphorylation; D011485:Protein Binding; D016601:RNA-Binding Proteins / Q000378:metabolism*
D048948:14-3-3 Proteins; D000954:Antigens, Surface; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; C098770:ELAVL1 protein, human; D016601:RNA-Binding Proteins; D016203:CDC2 Protein Kinase