p70 S6 Kinase Is Regulated by Protein Kinase Cζ and Participates in a Phosphoinositide 3-Kinase-Regulated Signalling Complex
Molecular and Cellular BiologyPublished 1 April 1999Open access
Angela Romanelli, Kathleen A. Martin, Alex Toker, John Blenis
Citations180
Generate an AI Snapshot to get a quick, structured summary of this paper.
Study Snapshot
ObjectiveStudy objective
MethodsResearch methodology
PopulationPopulation studied
Sample sizeSample sizes
OutcomesStudy outcomes here
ResultsStudy results comes here
LimitationsResearch study limitations comes here
A concise AI-generated summary of the paper will appear here once you click Generate AI Snapshot.
TL;DR
PI3-K-regulated atypical protein kinase C (PKC) isoform PKCζ is identified as an upstream regulator of p70S6K and evidence for a link between a phorbol ester-insensitive PKC isoform and p70 S6K is provided.
Abstract
p70 S6 kinase (p70S6K) is an important regulator of cell proliferation. Its activation by growth factor requires phosphorylation by various inputs on multiple sites. Data accumulated thus far support a model whereby p70S6K activation requires sequential phosphorylations at proline-directed residues in the putative autoinhibitory pseudosubstrate domain, as well as threonine 389. Threonine 229, a site in the catalytic loop is phosphorylated by phosphoinositide-dependent kinase 1 (PDK-1). Experimental evidence suggests that p70S6K activation requires a phosphoinositide 3-kinase (PI3-K)-dependent signal(s). However, the intermediates between PI3-K and p70S6K remain unclear. Here, we have identified PI3-K-regulated atypical protein kinase C (PKC) isoform PKCzeta as an upstream regulator of p70S6K. In coexpression experiments, we found that a kinase-inactive PKCzeta mutant antagonized activation of p70S6K by epidermal growth factor, PDK-1, and activated Cdc42 and PI3-K. While overexpression of a constitutively active PKCzeta mutant (myristoylated PKCzeta [myr-PKCzeta]) only modestly activated p70S6K, this mutant cooperated with PDK-1 activation of p70S6K. PDK-1-induced activation of a C-terminal truncation mutant of p70S6K was also enhanced by myr-PKCzeta. Moreover, we have found that p70S6K can associate with both PDK-1 and PKCzeta in vivo in a growth factor-independent manner, while PDK-1 and PKCzeta can also associate with each other, suggesting the existence of a multimeric PI3-K signalling complex. This work provides evidence for a link between a phorbol ester-insensitive PKC isoform and p70S6K. The existence of a PI3-K-dependent signalling complex may enable efficient activation of p70S6K in cells.
Keywords
Biochemistry, Genetics and Molecular Biology
CellAkt Phosphorylation of BAD Couples Survival Signals to the Cell-Intrinsic Death Machinery
5,706 Citations1997Sandeep Robert Datta, Henryk Dudek +5 more
Current BiologyCharacterization of a 3-phosphoinositide-dependent protein kinase which phosphorylates and activates protein kinase Bα
2,830 Citations1997Dario R. Alessi, Stephen R. James +5 more
NatureProtein kinase B (c-Akt) in phosphatidylinositol-3-OH kinase signal transduction
2,106 Citations1995Boudewijn Burgering, Paul J. Coffer
A role for PKB in PI(3)K-mediated signal transduction is suggested and a constructed Gag–PKB fusion protein, homologous to the v-akt oncogene, displays significantly increased ligand-independent kinase activity.
Current Opinion in Cell BiologyMechanisms and consequences of activation of protein kinase B/Akt
1,306 Citations1998Julian Downward
Activated PKB/Akt provides a survival signal that protects cells from apoptosis induced by various stresses, and also mediates a number of metabolic effects of insulin.
CellRapamycin-FKBP specifically blocks growth-dependent activation of and signaling by the 70 kd S6 protein kinases
1,158 Citations1992Jongkyeong Chung, Calvin J. Kuo +2 more
These studies identify a rapamycin-sensitive signaling pathway, argue for a ubiquitous role for FKBPs in signal transduction, indicate that FK506-FKBP-calcineurin complexes do not interfere with pp70S6K signaling, and show that in fibroblasts pp70 S6K, not RSK, is the physiological S6 kinase.
Proceedings of the National Academy of SciencesRAFT1 phosphorylation of the translational regulators p70 S6 kinase and 4E-BP1
1,141 Citations1998Patrick E. Burnett, Roxanne K. Barrow +3 more
It is shown that RAFT1 directly phosphorylates p70(S6k), 4E-BP1, and 4e-BP2 and that serum stimulates RAFT 1 kinase activity with kinetics similar to those of p70 (S6K) and 4E -BP1 phosphorylation.
ScienceProtein Kinase C Isotypes Controlled by Phosphoinositide 3-Kinase Through the Protein Kinase PDK1
1,108 Citations1998J. Ann Le Good, Wolfgang Ziegler +4 more
Phosphorylation sites in members of the protein kinase A, PKG, and PKC kinase subfamily are conserved and the PKB kinase PDK1 may be responsible for the phosphorylation of PKC isotypes.
ScienceProtein Kinase B Kinases That Mediate Phosphatidylinositol 3,4,5-Trisphosphate-Dependent Activation of Protein Kinase B
1,061 Citations1998Len Stephens, Karen E. Anderson +10 more
Four isoforms of these PKB kinases were purified from sheep brain and their heterologous expression augments receptor activation of PKB, which suggests they are the primary signal transducers that enable PtdIns(3,4,5)P3 or PTDIns- (3, 4)P2 to activate PKB and hence to control signaling pathways regulating cell survival, glucose uptake, and glycogen metabolism.
Molecular and Cellular BiologyPhosphatidylinositol 3-Kinase Activation Is Required for Insulin Stimulation of pp70 S6 Kinase, DNA Synthesis, and Glucose Transporter Translocation
1,013 Citations1994Bentley Cheatham, Chris J. Vlahos +4 more
Activation of PI 3-kinase plays a critical role in mammalian cells and is required for activation of pp70 S6 kinase and DNA synthesis and certain forms of intracellular vesicular trafficking but not mitogen-activated protein kinase or pp90 S6 Kinase activation.
Journal of Biological ChemistryActivation of the zeta isozyme of protein kinase C by phosphatidylinositol 3,4,5-trisphosphate.
970 Citations1993Hiroyuki Nakanishi, Kim Brewer +1 more
The results suggest that PKC zeta may be a target for PIP3 and thus may be involved in the signaling mechanism(s) for growth factors and oncogenes that increase phosphatidylinositol 3-kinase activity.
SciencePhosphorylation and Activation of p70 <sup>s6k</sup> by PDK1
835 Citations1998Nick Pullen, Patrick B. Dennis +5 more
A regulatory link between p70s6k and PKB was demonstrated, as PDK1 was found to selectively phosphorylate p70S6k at Thr229, whereas the catalytically inactivePDK1 blocked insulin-induced activation of p70 s6k.
Molecular and Cellular BiologyActivation of the Mitogen-Activated Protein Kinase/Extracellular Signal-Regulated Kinase Pathway by Conventional, Novel, and Atypical Protein Kinase C Isotypes
757 Citations1998Dorothee C. Schönwaßer, Richard Marais +2 more
A novel Raf desensitization induced by PKC-α is described, which acts to prevent further Raf stimulation by growth factors and demonstrates a necessary role for PKC and p42 MAPK activation in 12-O-tetradecanoylphorbol-13-acetate induced mitogenesis.
NaturePDGF- and insulin-dependent pp70S6k activation mediated by phosphatidylinositol-3-OH kinase
724 Citations1994Jongkyeong Chung, Timothy C. Grammar +3 more
It is reported that PI( 3)K mediates PDGF or insulin receptor signalling to pp70S6k, and PI(3)K-mediated activation of pp70s6k is independent of conventional protein kinase C isoforms.
Current BiologyRegulation of protein kinase C ζ by PI 3-kinase and PDK-1
617 Citations1998Margaret M. Chou, Weimin Hou +7 more
The results have identified PDK-1 as the kinase that phosphorylates and activates PKC zeta in the PI 3-kinase signaling pathway, and shows that a membrane-targeted PKCZeta is constitutively active in the absence of agonist stimulation.
Current Biology3-Phosphoinositide-dependent protein kinase 1 (PDK1) phosphorylates and activates the p70 S6 kinase in vivo and in vitro
581 Citations1998Dario R. Alessi, Mark T. Kozlowski +3 more
PDK1 is one of the components of the signaling pathway recruited by Pl 3-kinase for the activation of p70 S6 kinase as well as of PKB, and serves as a multifunctional effector downstream of the Pl 3 -kinase.
ScienceRas-Dependent Induction of Cellular Responses by Constitutively Active Phosphatidylinositol-3 Kinase
555 Citations1995Qianjin Hu, Anke Klippel +3 more
Findings show that Pl-3 kinase can stimulate diverse Ras-dependent cellular processes, including oocyte maturation and fos transcription.
FEBS LettersThe modular phosphorylation and activation of p70<sup>s6k</sup>
538 Citations1997Nick Pullen, George Thomas
A model of activation is proposed which divides p70s6k into four functional modules that cooperate in leading to full enzyme activity and it is suggested how candidate effectors of p70S6k activation might function by directing the phosphorylation of specific sites.
The EMBO JournalThe principal target of rapamycin‐induced p70s6k inactivation is a novel phosphorylation site within a conserved hydrophobic domain.
443 Citations1995Richard B. Pearson, Patrick B. Dennis +5 more
A combination of techniques are employed, including mass spectrometry, to demonstrate that the immunosuppressive agent rapamycin induces inactivation of p70s6k with no effect on other mitogen‐activated kinases, and that this effect is associated with selective dephosphorylation of three previously unidentified p70S6k phosphorylation sites.
Journal of Biological ChemistryProtein Kinase C-ζ as a Downstream Effector of Phosphatidylinositol 3-Kinase during Insulin Stimulation in Rat Adipocytes
436 Citations1997Mary L. Standaert, Lamar Galloway +4 more
It is suggested that insulin activates PKC-ζ through PI 3-kinase, and PKC -ζ may act as a downstream effector of PI 3 -kinase and contribute to the activation of GLUT4 translocation.
CellProtein kinase C ζ isoform is critical for mitogenic signal transduction
378 Citations1993Edurne Berra, María T. Diaz‐Meco +6 more
Experimental evidence is presented demonstrating that activation of zeta PKC is not only necessary but also sufficient by itself to activate maturation in oocytes and to produce deregulation of growth control in mouse fibroblasts, and proposing zETA PKC as a critical step downstream of p21ras in mitogenic signal transduction.
Current BiologyTranslocation of PDK-1 to the plasma membrane is important in allowing PDK-1 to activate protein kinase B
362 Citations1998Karen E. Anderson, John Coadwell +2 more
The effects of membrane localisation of PDK-1 on PKB activation are investigated, with binding of Ptdlns (3,4,5)P3 and/or PTDlns(3, 4)P2 to the PH domain of PDk-1 causes its translocation to the plasma membrane where it co-localises with PKB, significantly contributing to the scale of P KB activation.
CellThe 70 kDa S6 Kinase Complexes with and Is Activated by the Rho Family G Proteins Cdc42 and Rac1
294 Citations1996Margaret M. Chou, John Blenis
It is demonstrated that Rho family G proteins regulate pp70S6k activity in vivo, and Cdc42 and Rac1 form GTP-dependent complex with the catalytically inactive form of pp70s6k in vitro and in vitro, suggesting a mechanism by which these G proteins activate pp70 s6k.
Journal of Biological ChemistryActivation of Protein Kinase C (α, β, and ζ) by Insulin in 3T3/L1 Cells
289 Citations1997Gautam Bandyopadhyay, Mary L. Standaert +7 more
It is suggested that: (a) insulin activates PKC-zeta, as well asPKC-alpha and beta is required for, and may contribute to, insulin effects on glucose transport in 3T3/L1 cells.
The EMBO JournalEvidence for a role of MEK and MAPK during signal transduction by protein kinase C zeta.
267 Citations1995Edurne Berra, María T. Diaz‐Meco +6 more
It is shown here that MAPK and MEK are activated in vivo by an active mutant of zeta PKC, and that a kinase‐defective dominant negative mutant of zeppelin PKC dramatically impairs the activation of both MEK and MAPK by serum and tumour necrosis factor (TNF alpha).
Journal of Biological ChemistryAn array of insulin-activated, proline-directed serine/threonine protein kinases phosphorylate the p70 S6 kinase.
250 Citations1992Nishit K. Mukhopadhyay, Daniel J. Price +4 more
Current Opinion in Cell BiologyThe 70 kDa S6 kinase: regulation of a kinase with multiple roles in mitogenic signalling
241 Citations1995Margaret M. Chou, John Blenis
The activation of the 70kDa S6 kinase, pp70S6k, is a well documented mitogenic response, yet until recently little was known of how it is activated, or of the identities of its crucial targets.
Molecular and Cellular BiologyMultiple Independent Inputs Are Required for Activation of the p70 S6 Kinase
229 Citations1995Qing-Ping Weng, Khurshid Iqbal Andrabi +3 more
The present study shows that a recombinant p70 deleted of the carboxy-terminal tail nevertheless exhibits a basal and serum-stimulated 40S kinase activity and susceptibility to inhibition by wortmannin very similar to those of the parent, full-length p70 kinase.
Proceedings of the National Academy of SciencesPhosphatidylinositol 3-kinase signals activation of p70 S6 kinase in situ through site-specific p70 phosphorylation.
207 Citations1995Q P Weng, Khurshid Iqbal Andrabi +4 more
PI 3-kinase provides a signal necessary for the mitogen activation of the p70 S6 kinase, which directs the site-specific phosphorylation of Thr-252 in the p 70 catalytic domain through a distinctive signal transduction pathway.
Journal of Biological ChemistryRapamycin, Wortmannin, and the Methylxanthine SQ20006 Inactivate p70s6k by Inducing Dephosphorylation of the Same Subset of Sites
165 Citations1995Jeung-Whan Han, Richard B. Pearson +2 more
There are two kinase signaling pathways that must converge to activate p70s6k and that only one of these pathways is sensitive to rapamycin, wortmannin, and methylxanthine inhibition, leading to the hypothesis that the inhibitory actions ofmethylxanthines on p70S6k activity are not through activating protein kinase A but through inhibition of an upstream kinase.
Molecular and Cellular BiologyEvidence for a Role of Protein Kinase C ζ Subspecies in Maturation of <i>Xenopus laevis</i> Oocytes
159 Citations1992Isabel Domínguez, María T. Díaz‐Meco +6 more
Data are presented that show the involvement of protein kinase C zeta subspecies in the channelling of the mitogenic signal activated by insulin-p21ras-PC-PLC in Xenopus oocytes as well as the lack of a critical role of protein Kinase C isotypes alpha, beta, gamma, delta, and epsilon in these pathways.
Journal of Biological ChemistryPhosphatidylinositol 3-Kinase-dependent Activation of Protein Kinase C-ζ in Bacterial Lipopolysaccharide-treated Human Monocytes
140 Citations1997Patricia Herrera-Velit, Keith L. Knutson +1 more
Molecular and Cellular BiologyRequirement of Protein Kinase Cζ for Stimulation of Protein Synthesis by Insulin
129 Citations1997Raúl Méndez, Gwen Kollmorgen +2 more
PI3K appears to represent a bifurcation in the insulin signaling pathway, one branch leading through PKC zeta to generalprotein synthesis and one, through Akt and the target of rapamycin (mTOR), to growth-regulated protein synthesis and cell cycle progression.
Proceedings of the National Academy of SciencesStructural and functional analysis of pp70S6k.
126 Citations1995Lynn Cheatham, Mercè Monfar +2 more
Molecular and Cellular BiologyDual Requirement for a Newly Identified Phosphorylation Site in p70 <sup>s6k</sup>
105 Citations1997Bettina A. Moser, Patrick B. Dennis +6 more
Three new phosphorylation sites are described, T367, S371, and T447, all of which have a recognition motif similar to that of the first set of sites, and only S371 is conserved in p70s6k homologs from Drosophila melanogaster, Arabidopsis thaliana, and Saccharomyces cerevisiae.
PubMedActivation of protein kinase C-zeta and phosphatidylinositol 3'-kinase and promotion of macrophage differentiation by insulin-like growth factor-I.
89 Citations1998Qiang Liu, Wanshan Ning +3 more
It is established that PKC-zeta is a putative downstream target of PI 3-kinase that is activated during IGF-I-promoted macrophage differentiation.
Biochemical JournalThe broad specificity of dominant inhibitory protein kinase C mutants infers a common step in phosphorylation
73 Citations1998Pilar GARCIA-PARAMIO, Yolanda Cabrerizo +2 more
Results provide evidence for the involvement of a common step in the phosphorylation of all PKC isotypes, and show that inhibition required the full-length mutant protein.
The Journal of ImmunologyActivation of Protein Kinase C-ζ and Phosphatidylinositol 3′-Kinase and Promotion of Macrophage Differentiation by Insulin-Like Growth Factor-I
73 Citations1998Qiang Liu, Wei Ning +3 more
It is established that PKC-ζ is a putative downstream target of PI 3-kinase that is activated during IGF-I-promoted macrophage differentiation.
Biochemical JournalPlatelet-derived growth factor activation of mitogen-activated protein kinase depends on the sequential activation of phosphatidylcholine-specific phospholipase C, protein kinase C-ζ and Raf-1
67 Citations1997M.C.M. van Dijk, Henk Hilkmann +1 more
It is reported that MAPK activation by exogenous PC-PLC depends on Raf-1 activation, and PKC-zeta co-immunoprecipitates with, phoshorylates and activates Raf- 1, suggesting that in the PDGF- and PC- PLC-activated MAPK pathway, PKC -zeta operates in a signalling complex as a direct activator of Raf-2.
Molecular and Cellular BiologyStudies of Partially Transforming Polyomavirus Mutants Establish a Role for Phosphatidylinositol 3-Kinase in Activation of pp70 S6 Kinase
28 Citations1996Jean Dahl, Robert Freund +2 more