scholarly journals p90 ribosomal S6 kinase 2 is associated with and dephosphorylated by protein phosphatase 2Cδ

2004 ◽  
Vol 382 (2) ◽  
pp. 425-431 ◽  
Author(s):  
Ulrik DOEHN ◽  
Steen GAMMELTOFT ◽  
Shi-Hsiang SHEN ◽  
Claus J. JENSEN

RSK2 (p90 ribosomal S6 kinase 2) is activated via the ERK (extracellular-signal-regulated kinase) pathway by phosphorylation on four sites: Ser227 in the activation loop of the N-terminal kinase domain, Ser369 in the linker, Ser386 in the hydrophobic motif and Thr577 in the C-terminal kinase domain of RSK2. In the present study, we demonstrate that RSK2 is associated in vivo with PP2Cδ (protein phosphatase 2Cδ). In epidermal growth factorstimulated cells, RSK2 is partially dephosphorylated on all four sites in an Mn2+-dependent manner, leading to reduced protein kinase activity. Furthermore, PP2Cδ is phosphorylated by ERK on Thr315 and Thr333 in the catalytic domain. Mutation of Thr315 and Thr333 to alanine in a catalytically inactive mutant PP2Cδ(H154D) (His154→Asp) increases the association with RSK2 significantly, whereas mutation to glutamate, mimicking phosphorylation, reduces the binding of RSK2. The domains of interaction are mapped to the N-terminal extension comprising residues 1–71 of PP2Cδ and the N-terminal kinase domain of RSK2. The interaction is specific, since PP2Cδ associates with RSK1–RSK4, MSK1 (mitogen- and stress-activated kinase 1) and MSK2, but not with p70 S6 kinase or phosphoinositide-dependent kinase 1. We conclude that RSK2 is associated with PP2Cδ in vivo and is partially dephosphorylated by it, leading to reduced kinase activity.

Author(s):  
Margarita Malakhova ◽  
Igor Kurinov ◽  
Kangdong Liu ◽  
Duo Zheng ◽  
Igor D'Angelo ◽  
...  

Zygote ◽  
2002 ◽  
Vol 10 (1) ◽  
pp. 31-36 ◽  
Author(s):  
K. Sugiura ◽  
K. Naito ◽  
N. Iwamori ◽  
H. Kagii ◽  
S. Goto ◽  
...  

The normal kinetics of ribosomal S6 kinase (RSK) during the meiotic maturation of porcine oocytes were examined. The phosphorylation states of RSK and extracellular signal-regulated kinase (ERK), major mitogen-activated protein (MAP) kinases in maturating porcine oocytes, were detected by Western blotting analysis. The S6 protein kinase activity was assayed using a specific substrate peptide which contained the major phosphorylation sites of S6 kinase. Full phosphorylation of RSK was correlated with ERK phosphorylation and was observed before germinal vesicle breakdown. S6 kinase activity was low in both freshly isolated and 20 h cultured oocytes. S6 kinase activity was significantly elevated in matured oocytes to a level about 6 times higher than that in freshly isolated oocytes. Furthermore, full phosphorylation of RSK was inhibited when oocytes were treated with U0126, a specific MAP kinase kinase inhibitor, in dose-dependent manner, indicating that RSK is one of the substrates of MAP kinase. These results suggest that the activation of RSK is involved in the regulation of meiotic maturation of porcine oocytes.


PLoS ONE ◽  
2009 ◽  
Vol 4 (11) ◽  
pp. e8044 ◽  
Author(s):  
Margarita Malakhova ◽  
Igor Kurinov ◽  
Kangdong Liu ◽  
Duo Zheng ◽  
Igor D'Angelo ◽  
...  

2013 ◽  
Vol 305 (7) ◽  
pp. H1010-H1019 ◽  
Author(s):  
Catherine L. Passariello ◽  
Marjorie Gayanilo ◽  
Michael D. Kritzer ◽  
Hrishikesh Thakur ◽  
Zoharit Cozacov ◽  
...  

Myocardial interstitial fibrosis is an important contributor to the development of heart failure. Type 3 p90 ribosomal S6 kinase (RSK3) was recently shown to be required for concentric myocyte hypertrophy under in vivo pathological conditions. However, the role of RSK family members in myocardial fibrosis remains uninvestigated. Transgenic expression of α-tropomyosin containing a Glu180Gly mutation (TM180) in mice of a mixed C57BL/6:FVB/N background induces a cardiomyopathy characterized by a small left ventricle, interstitial fibrosis, and diminished systolic and diastolic function. Using this mouse model, we now show that RSK3 is required for the induction of interstitial fibrosis in vivo. TM180 transgenic mice were crossed to RSK3 constitutive knockout ( RSK3−/−) mice. Although RSK3 knockout did not affect myocyte growth, the decreased cardiac function and mild pulmonary edema associated with the TM180 transgene were attenuated by RSK3 knockout. The improved cardiac function was consistent with reduced interstitial fibrosis in the TM180; RSK3−/− mice as shown by histology and gene expression analysis, including the decreased expression of collagens. The specific inhibition of RSK3 should be considered as a potential novel therapeutic strategy for improving cardiac function and the prevention of sudden cardiac death in diseases in which interstitial fibrosis contributes to the development of heart failure.


2001 ◽  
Vol 21 (3) ◽  
pp. 755-764 ◽  
Author(s):  
Tatsushi Wakayama ◽  
Tae Kondo ◽  
Seiko Ando ◽  
Kunihiro Matsumoto ◽  
Katsunori Sugimoto

ABSTRACT In eukaryotes, the ATM and ATR family proteins play a critical role in the DNA damage and replication checkpoint controls. These proteins are characterized by a kinase domain related to the phosphatidylinositol 3-kinase, but they have the ability to phosphorylate proteins. In budding yeast, the ATR family protein Mec1/Esr1 is essential for checkpoint responses and cell growth. We have isolated the PIE1 gene in a two-hybrid screen for proteins that interact with Mec1, and we show that Pie1 interacts physically with Mec1 in vivo. Like MEC1, PIE1is essential for cell growth, and deletion of the PIE1 gene causes defects in the DNA damage and replication block checkpoints similar to those observed in mec1Δ mutants. Rad53 hyperphosphorylation following DNA damage and replication block is also decreased in pie1Δ cells, as in mec1Δcells. Pie1 has a limited homology to fission yeast Rad26, which forms a complex with the ATR family protein Rad3. Mutation of the region in Pie1 homologous to Rad26 results in a phenotype similar to that of thepie1Δ mutation. Mec1 protein kinase activity appears to be essential for checkpoint responses and cell growth. However, Mec1 kinase activity is unaffected by the pie1Δ mutation, suggesting that Pie1 regulates some essential function other than Mec1 kinase activity. Thus, Pie1 is structurally and functionally related to Rad26 and interacts with Mec1 to control checkpoints and cell proliferation.


2009 ◽  
Vol 42 (2) ◽  
pp. 134-141 ◽  
Author(s):  
Matthias Fischer ◽  
Patricia Marques Pereira ◽  
Bettina Holtmann ◽  
Christian M. Simon ◽  
Andre Hanauer ◽  
...  

2004 ◽  
Vol 24 (7) ◽  
pp. 3025-3035 ◽  
Author(s):  
Michele S. Woo ◽  
Yasutaka Ohta ◽  
Isaac Rabinovitz ◽  
Thomas P. Stossel ◽  
John Blenis

ABSTRACT The Ras-mitogen-activated protein (Ras-MAP) kinase pathway regulates various cellular processes, including gene expression, cell proliferation, and survival. Ribosomal S6 kinase (RSK), a key player in this pathway, modulates the activities of several cytoplasmic and nuclear proteins via phosphorylation. Here we report the characterization of the cytoskeletal protein filamin A (FLNa) as a membrane-associated RSK target. We show that the N-terminal kinase domain of RSK phosphorylates FLNa on Ser2152 in response to mitogens. Inhibition of MAP kinase signaling with UO126 or mutation of Ser2152 to Ala on FLNa prevents epidermal growth factor (EGF)-stimulated phosphorylation of FLNa in vivo. Furthermore, phosphorylation of FLNa on Ser2152 is significantly enhanced by the expression of wild-type RSK and antagonized by kinase-inactive RSK or specific reduction of endogenous RSK. Strikingly, EGF-induced, FLNa-dependent migration of human melanoma cells is significantly reduced by UO126 treatment. Together, these data provide substantial evidence that RSK phosphorylates FLNa on Ser2152 in vivo. Given that phosphorylation of FLNa on Ser2152 is required for Pak1-mediated membrane ruffling, our results suggest a novel role for RSK in the regulation of the actin cytoskeleton.


2017 ◽  
Author(s):  
Hu Zhu ◽  
Ryan T. Strachan ◽  
Daniel Urban ◽  
Martilias Farrell ◽  
Wesley K. Kroeze ◽  
...  

Coffin-Lowry syndrome (CLS) is an X-linked syndromic form of mental retardation characterized by various skeletal dysmorphisms, moderate to severe mental retardation, and in some cases, psychosis. CLS is caused by loss-of-function mutations of the p90 ribosomal S6 kinase 2 (RPS6KA3) gene encoding a growth factor-regulated serine/threonine kinase, ribosomal S6 kinase 2 (RSK2). We previously identified RSK2 as a novel interacting protein that tonically inhibits 5-HT2A receptor signaling by phosphorylating Ser-314 within the third intracellular loop. To determine if RSK2 inhibits 5-HT2A receptor signaling in vivo and whether disruption of RSK2 could lead to schizophrenia-like behaviors - as is seen in some CLS patients - we genetically disrupted the function of RSK2 either globally or selectively in forebrain pyramidal neurons in mice. Both global and forebrain-selective RSK2 deletion augmented the locomotor responses to the psychotomimetic drugs phencyclidine (PCP) and amphetamine (AMPH). Significantly, forebrain-selective deletion of RSK2 augmented 5-HT2A receptor signaling as exemplified by enhanced 5-HT2A-mediated c-fos activation and head-twitch response without altering the levels or distribution of 5-HT2A receptor protein. Thus, RSK2 modulates 5HT2A receptor function in vivo, and disruption of RSK2 leads to augmented psychostimulant-induced responses reminiscent of those seen in many animal models of schizophrenia. These findings strengthen the association between 5-HT2A receptor dysfunction and psychosis, and provide a potential mechanism underlying the schizophrenia-like symptoms present in some CLS patients.


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