A new tool to dissect the function of p70 S6 kinase

2010 ◽  
Vol 431 (2) ◽  
pp. e1-e3 ◽  
Author(s):  
Benoit Bilanges ◽  
Bart Vanhaesebroeck
Keyword(s):  
Metabolic Disease ◽  
Insulin Resistance ◽  
Mammalian Target Of Rapamycin ◽  
Specific Protein ◽  
Selective Inhibitor ◽  
S6 Kinase ◽  
Substrate Specificities ◽  
P70 S6 Kinase ◽  
Biochemical Journal

Developing small-molecule inhibitors that are highly selective for specific protein kinases has been and remains a serious challenge. This especially applies to members of families of related kinases with overlapping substrate specificities, such as the serine/threonine kinases of the AGC family. In this issue of the Biochemical Journal, Dario Alessi's group, in a collaboration with Pfizer, report on PF-4708671, a potent and highly selective inhibitor of S6K1 (p70 S6 kinase 1) in vitro and in cells. S6K1 is an AGC family member and a crucial effector of the mTORC1 (mammalian target of rapamycin complex 1) kinase. This is the first reported inhibitor that is highly selective for S6K1. This compound will help to understand the signalling and physiological roles of S6K1, and to dissect signalling downstream of mTORC1. S6K1 inhibitors may ultimately be useful in the treatment of diseases such as cancer where S6K1 is overexpressed, but most importantly in metabolic disease such as insulin resistance and obesity.

scholarly journals Substrate specificities of tyrosine-specific protein kinases toward cytoskeletal proteins in vitro.

1986 ◽  
Vol 261 (31) ◽  
pp. 14797-14803 ◽  
Author(s):  
T Akiyama ◽  
T Kadowaki ◽  
E Nishida ◽  
T Kadooka ◽  
H Ogawara ◽  
...  
Keyword(s):  
Protein Kinases ◽  
Specific Protein ◽  
Cytoskeletal Proteins ◽  
Substrate Specificities

scholarly journals Specific activation of p85-p110 phosphatidylinositol 3'-kinase stimulates DNA synthesis by ras- and p70 S6 kinase-dependent pathways.

1997 ◽  
Vol 17 (1) ◽  
pp. 248-255 ◽  
Author(s):  
J McIlroy ◽  
D Chen ◽  
C Wjasow ◽  
T Michaeli ◽  
J M Backer
Keyword(s):  
Dna Synthesis ◽  
Affinity Purification ◽  
Specific Inhibitor ◽  
Brdu Incorporation ◽  
Glutathione S Transferase ◽  
Intact Cells ◽  
S6 Kinase ◽  
P70 S6 Kinase ◽  
Quiescent Cells

We have developed a polyclonal antibody that activates the heterodimeric p85-p110 phosphatidylinositol (PI) 3'-kinase in vitro and in microinjected cells. Affinity purification revealed that the activating antibody recognized the N-terminal SH2 (NSH2) domain of p85, and the antibody increased the catalytic activity of recombinant p85-p110 dimers threefold in vitro. To study the role of endogenous PI 3'-kinase in intact cells, the activating anti-NSH2 antibody was microinjected into GRC + LR73 cells, a CHO cell derivative selected for tight quiescence during serum withdrawal. Microinjection of anti-NSH2 antibodies increased bromodeoxyuridine (BrdU) incorporation fivefold in quiescent cells and enhanced the response to serum. These data reflect a specific activation of PI 3'-kinase, as the effect was blocked by coinjection of the appropriate antigen (glutathione S-transferase-NSH2 domains from p85 alpha), coinjection of inhibitory anti-p110 antibodies, or treatment of cells with wortmannin. We used the activating antibodies to study signals downstream from PI 3'-kinase. Although treatment of cells with 50 nM rapamycin only partially decreased anti-NSH2-stimulated BrdU incorporation, coinjection with an anti-p70 S6 kinase antibody effectively blocked anti-NSH2-stimulated DNA synthesis. We also found that coinjection of inhibitory anti-ras antibodies blocked both serum- and anti-NSH2-stimulated BrdU incorporation by approximately 60%, and treatment of cells with a specific inhibitor of MEK abolished antibody-stimulated BrdU incorporation. We conclude that selective activation of physiological levels of PI 3'-kinase is sufficient to stimulate DNA synthesis in quiescent cells. PI 3'-kinase-mediated DNA synthesis requires both p70 S6 kinase and the P21ras/MEK pathway.

scholarly journals Immunopurified Mammalian Target of Rapamycin Phosphorylates and Activates p70 S6 Kinase αin Vitro

1999 ◽  
Vol 274 (48) ◽  
pp. 34493-34498 ◽  
Author(s):  
Shuji Isotani ◽  
Kenta Hara ◽  
Chiharu Tokunaga ◽  
Hitomi Inoue ◽  
Joseph Avruch ◽  
...  
Keyword(s):  
Mammalian Target Of Rapamycin ◽  
Target Of Rapamycin ◽  
S6 Kinase ◽  
P70 S6 Kinase

scholarly journals The mechanism by which epidermal growth factor inhibits glycogen synthase kinase 3 in A431 cells

1994 ◽  
Vol 303 (1) ◽  
pp. 27-31 ◽  
Author(s):  
Y Saito ◽  
J R Vandenheede ◽  
P Cohen
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Glycogen Synthase ◽  
Glycogen Synthase Kinase ◽  
Glycogen Synthase Kinase 3 ◽  
A431 Cells ◽  
S6 Kinase ◽  
P70 S6 Kinase ◽  
Epidermal Growth

Glycogen synthase kinase 3 (GSK3) was inhibited by 50% within 5 min when A431 cells were stimulated with epidermal growth factor (EGF). The inhibition was unaffected by rapamycin at concentrations which blocked the activation of p70 S6 kinase, and reversed by incubation with protein phosphatase-1. EGF stimulation of A431 cells inhibited GSK3 alpha and GSK3 beta to a similar extent, and inhibition was accompanied by phosphorylation of the tryptic peptides containing the serine residues phosphorylated in vitro by p70 S6 kinase or MAP kinase-activated protein (MAPKAP) kinase-1 beta (also termed Rsk-2). These results demonstrate that EGF inhibits GSK3 by inducing phosphorylation of a serine residue and that GSK3 is not phosphorylated in vivo by either p70 S6 kinase or protein kinase C.

Serum Lipid and Protein Changes in Healthy Dyslipidemic Subjects Given a Selective Inhibitor of p70 S6 Kinase-1

2017 ◽  
Vol 58 (4) ◽  
pp. 412-424 ◽  
Author(s):  
Jennifer K. Leohr ◽  
Debra Luffer-Atlas ◽  
M. Jane Luo ◽  
David J. DeBrota ◽  
Colin Green ◽  
...  
Keyword(s):  
Serum Lipid ◽  
Selective Inhibitor ◽  
S6 Kinase ◽  
P70 S6 Kinase

scholarly journals Phosphoproteomic Analysis of Neonatal Regenerative Myocardium Revealed Important Roles of Checkpoint Kinase 1 via Activating Mammalian Target of Rapamycin C1/Ribosomal Protein S6 Kinase b-1 Pathway

Circulation ◽  
2020 ◽  
Vol 141 (19) ◽  
pp. 1554-1569 ◽  
Author(s):  
Yi Fan ◽  
Yiwei Cheng ◽  
Yafei Li ◽  
Bingrui Chen ◽  
Zimu Wang ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Ribosomal Protein ◽  
Mammalian Target Of Rapamycin ◽  
Border Zone ◽  
Target Of Rapamycin ◽  
Cardiomyocyte Proliferation ◽  
S6 Kinase ◽  
Ribosomal Protein S6 ◽  
Ribosomal Protein S6 Kinase

Background: In mammals, regenerative therapy after myocardial infarction is hampered by the limited regenerative capacity of adult heart, whereas a transient regenerative capacity is maintained in the neonatal heart. Systemic phosphorylation signaling analysis on ischemic neonatal myocardium might be helpful to identify key pathways involved in heart regeneration. Our aim was to define the kinase-substrate network in ischemic neonatal myocardium and to identify key pathways involved in heart regeneration after ischemic insult. Methods: Quantitative phosphoproteomics profiling was performed on infarct border zone of neonatal myocardium, and kinase-substrate network analysis revealed 11 kinases with enriched substrates and upregulated phosphorylation levels, including checkpoint kinase 1 (CHK1) kinase. The effect of CHK1 on cardiac regeneration was tested on Institute of Cancer Research CD1 neonatal and adult mice that underwent apical resection or myocardial infarction. Results: In vitro, CHK1 overexpression promoted whereas CHK1 knockdown blunted cardiomyocyte proliferation. In vivo, inhibition of CHK1 hindered myocardial regeneration on resection border zone in neonatal mice. In adult myocardial infarction mice, CHK1 overexpression on infarct border zone upregulated mammalian target of rapamycin C1/ribosomal protein S6 kinase b-1 pathway, promoted cardiomyocyte proliferation, and improved cardiac function. Inhibiting mammalian target of rapamycin activity by rapamycin blunted the neonatal cardiomyocyte proliferation induced by CHK1 overexpression in vitro. Conclusions: Our study indicates that phosphoproteome of neonatal regenerative myocardium could help identify important signaling pathways involved in myocardial regeneration. CHK1 is found to be a key signaling responsible for neonatal regeneration. Myocardial overexpression of CHK1 could improve cardiac regeneration in adult hearts by activating the mammalian target of rapamycin C1/ribosomal protein S6 kinase b-1 pathway. Thus, CHK1 might serve as a potential novel target in myocardial repair after myocardial infarction.

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