Tandem phosphorylation of serines 221 and 318 by protein kinase Cdelta coordinates mRNA binding and nucleocytoplasmic shuttling of HuR
Authors: Harald Schwalbe
Wolfgang Eberhardt
Anke Doller
Josef Pfeilschifter
Kai Schlepckow
Journal: Molecular and Cellular Biology (2010)
Discipline: MOLECULAR BIOLOGY & GENETICS
Keywords: mRNA stabilization; HuR; phosphorylation; Angiotensin II; PKCdelta
Affiliations: Pharmazentrum Frankfurt/ZAFES, Klinikum der Johann Wolfgang Goethe-Universität Frankfurt am Main, Theodor-Stern-Kai 7, D-60590 Frankfurt am Main, Germany., Institute for Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-Universität Frankfurt am Main, Frankfurt am Main, Germany, Pharmazentrum Frankfurt/ZAFES, Klinikum der Johann Wolfgang Goethe-Universität Frankfurt am Main

Abstract:  Stabilization of mRNA by the ubiquitous RNA binding protein human antigen R (HuR), a member of the embryonic lethal abnormal vision (ELAV) protein family, requires canonical binding to AU-rich element (ARE)-bearing target mRNA and export of nuclear HuR-mRNA complexes to the cytoplasm. In human mesangial cells (HMC) both processes are induced by angiotensin II (AngII) via protein kinase Cdelta (PKCdelta)-triggered serine phosphorylation of HuR. By testing different point-mutated Flag-tagged HuR proteins, we found that Ser 318 within RNA recognition motif 3 (RRM3) is essential for AngII-induced binding to ARE-bearing mRNA but irrelevant for nucleocytoplasmic HuR shuttling. Conversely, mutation at Ser 221 within the HuR hinge region prevents AngII-triggered HuR export without affecting mRNA binding of HuR. Using phosphorylation state-specific antibodies, we found a transient increase in HuR phosphorylation at both serines by AngII. Functionally, PKCdelta mediates the AngII-induced stabilization of prominent HuR target mRNAs, including those of cyclin A, cyclin D(1), and cyclooxygenase-2 (COX-2), and is indispensable for AngII-triggered migration and wound healing of HMC. Our data suggest a regulatory paradigm wherein a simultaneous phosphorylation at different domains by PKCdelta coordinates mRNA binding and nucleocytoplasmic shuttling of HuR, both of which events are essentially involved in the stabilization of HuR target mRNAs and relevant cell functions. 

Retracted: No

PubPeer comments:
 2017 correction. http: mcb.asm.org content 37 13 e00151-17.full , 
 From the Correction:  *Fig. 1D: The Western blot image of u03b2-actin was an inadvertent duplication of the actin blot shown in Fig. 1C. * Here is the original Figure 1C D, with the duplications marked in red, as reported to the journal in September 2016. ![file]  Fig. 6A: Photos showing the vehicle panel at 24 h for the siRNA-HuR group and the +AngII panel at 0 h for the same group were inadvertently interchanged during the import of original photographs for arrangement as one multipanel figure. Additionally, the photo showing the +AngII panel at 0 h for the siRNA-HuR group was an inadvertent duplication of the photo showing the vehicle panel at 0 h for the same group due to a mislabeling in the file names. Here is the original Figure 6A with the duplication marked in pink, as reported to the journal. ![file] I thank the authors for correcting these errors. This paper was part of a structured search for image duplications in Molecular and Cellular Biology paper, which was published here: https: mcb.asm.org content 38 20 e00309-18.long ,