For a PDK1 inhibitor, the substrate matters

2010 ◽  
Vol 433 (2) ◽  
pp. e1-e2 ◽  
Author(s):  
Zachary A. Knight
Keyword(s):  
Cell Growth ◽  
Protein Kinases ◽  
Cell Signalling ◽  
Central Component ◽  
Specific Inhibition ◽  
Biochemical Journal ◽  
Regulate Cell Growth ◽  
Kinetics Of ◽  
Kinetics Of Inhibition ◽  
Phosphoinositide Dependent Kinase

More than 20 protein kinases are directly activated by 3-phosphoinositide-dependent kinase 1 (PDK1), which is a central component of the pathways that regulate cell growth, proliferation and survival. Despite the importance of PDK1 in cell signalling, highly selective PDK1 inhibitors have not been described. In this issue of the Biochemical Journal, Dario Alessi's group and their collaborators at GlaxoSmithKline report GSK2334470, a potent and selective PDK1 inhibitor. They show that this compound blocks the phosphorylation of known PDK1 substrates, but surprisingly find that the potency and kinetics of inhibition vary for different PDK1 targets. This substrate-specific inhibition has implications for the development of PDK1 inhibitors as drugs.

The Kinetics of Inhibition of the Action of Thrombin by the Fibrinopeptides Formed during the Clotting of Fibrinogen

1966 ◽  
Vol 16 (01/02) ◽  
pp. 277-295 ◽  
Author(s):  
A Silver ◽  
M Murray
Keyword(s):  
Amino Acids ◽  
Competitive Inhibition ◽  
Amorphous Material ◽  
Peptide Bond ◽  
Initial Reaction ◽  
Reaction Products ◽  
Coagulation Mechanism ◽  
Kinetics Of ◽  
Kinetics Of Inhibition ◽  
Burk Plot

SummaryVarious investigators have separated the coagulation products formed when fibrinogen is clotted with thrombin and identified fibrinopeptides A and B. Two other peaks are observed in the chromatogram of the products of coagulation, but these have mostly been dismissed by other workers. They have been identified by us as amino acids, smaller peptides and amorphous material (37). We have re-chromatographed these peaks and identified several amino acids. In a closed system of fibrinogen and thrombin, the only reaction products should be fibrin and peptide A and peptide B. This reasoning has come about because thrombin has been reported to be specific for the glycyl-arginyl peptide bond. It is suggested that thrombin also breaks other peptide linkages and the Peptide A and Peptide B are attacked by thrombin to yield proteolytic products. Thrombin is therefore probably not specific for the glycyl-arginyl bond but will react on other linkages as well.If the aforementioned is correct then the fibrinopeptides A and B would cause an inhibition with the coagulation mechanism itself. We have shown that an inhibition does occur. We suggest that there is an autoinhibition to the clotting mechanism that might be a control mechanism in the human body.The experiment was designed for coagulation to occur under controlled conditions of temperature and time. Purified reactants were used. We assembled an apparatus to record visually the speed of the initial reaction, the rate of the reaction, and the density of the final clot formed after a specific time.The figures we derived made available to us data whereby we could calculate and plot the information to show the mechanism and suggest that such an inhibition does exist and also further suggest that it might be competitive.In order to prove true competitive inhibition it is necessary to fulfill the criteria of the Lineweaver-Burk plot. This has been done. We have also satisfied other criteria of Dixon (29) and Bergman (31) that suggest true competitive inhibition.

scholarly journals Modular evolution of phosphorylation-based signalling systems

2012 ◽  
Vol 367 (1602) ◽  
pp. 2540-2555 ◽  
Author(s):  
Jing Jin ◽  
Tony Pawson
Keyword(s):  
Protein Kinases ◽  
Genetic Recombination ◽  
Cell Signalling ◽  
Peptide Motifs ◽  
Regulatory Processes ◽  
Modular Evolution ◽  
Interaction Domains ◽  
Evolutionary Progression ◽  
Signalling Systems ◽  
Selection Of

Phosphorylation sites are formed by protein kinases (‘writers’), frequently exert their effects following recognition by phospho-binding proteins (‘readers’) and are removed by protein phosphatases (‘erasers’). This writer–reader–eraser toolkit allows phosphorylation events to control a broad range of regulatory processes, and has been pivotal in the evolution of new functions required for the development of multi-cellular animals. The proteins that comprise this system of protein kinases, phospho-binding targets and phosphatases are typically modular in organization, in the sense that they are composed of multiple globular domains and smaller peptide motifs with binding or catalytic properties. The linkage of these binding and catalytic modules in new ways through genetic recombination, and the selection of particular domain combinations, has promoted the evolution of novel, biologically useful processes. Conversely, the joining of domains in aberrant combinations can subvert cell signalling and be causative in diseases such as cancer. Major inventions such as phosphotyrosine (pTyr)-mediated signalling that flourished in the first multi-cellular animals and their immediate predecessors resulted from stepwise evolutionary progression. This involved changes in the binding properties of interaction domains such as SH2 and their linkage to new domain types, and alterations in the catalytic specificities of kinases and phosphatases. This review will focus on the modular aspects of signalling networks and the mechanism by which they may have evolved.

scholarly journals Serum deprivation inhibits the transcriptional co-activator YAP and cell growth via phosphorylation of the 130-kDa isoform of Angiomotin by the LATS1/2 protein kinases

2013 ◽  
Vol 110 (43) ◽  
pp. 17368-17373 ◽  
Author(s):  
J. J. Adler ◽  
D. E. Johnson ◽  
B. L. Heller ◽  
L. R. Bringman ◽  
W. P. Ranahan ◽  
...  
Keyword(s):  
Cell Growth ◽  
Protein Kinases ◽  
Serum Deprivation

Kinetics of inhibition of purified bovine neutrophil matrix metalloproteinase 9 by low–molecular-weight inhibitors

2009 ◽  
Vol 70 (5) ◽  
pp. 633-639 ◽  
Author(s):  
Gregory A. Bannikov ◽  
Jeffrey Lakritz ◽  
Christopher Premanandan ◽  
John S. Mattoon ◽  
Eric J. Abrahamsen
Keyword(s):  
Molecular Weight ◽  
Matrix Metalloproteinase ◽  
Matrix Metalloproteinase 9 ◽  
Low Molecular Weight ◽  
Kinetics Of ◽  
Metalloproteinase 9 ◽  
Kinetics Of Inhibition ◽  
Bovine Neutrophil

G alpha(i-2) mediates renal LLC-PK1 growth by a Raf-independent activation of p42/p44 MAP kinase

1997 ◽  
Vol 272 (2) ◽  
pp. F273-F282 ◽  
Author(s):  
T. B. Kinane ◽  
I. Kang ◽  
A. Chu ◽  
S. H. Chin ◽  
L. Ercolani
Keyword(s):  
Cell Growth ◽  
Protein Kinases ◽  
Doubling Time ◽  
Active Form ◽  
Renal Cells ◽  
Downstream Effectors ◽  
Mitogen Activated Protein ◽  
Cell Doubling Time ◽  
Cell Growth And Differentiation ◽  
Maximal Expression

The protooncogene G alpha(i-2) plays a pivotal role in signaling pathways that control renal cell growth and differentiation. Mitogen-activated protein kinases (MAPKs) are potential downstream effectors for G alpha(i-2) in these pathways. In predifferentiated LLC-PK1 renal cells, the temporal maximal expression of G alpha(i-2) coincided with maximal activation of MAPK(p42/p44). By contrast, pertussis toxin treatment of these cells inhibited cell growth and reduced MAPK(p42/p44) activity by 30%. These findings reflected upstream activation of MAPK kinase (MEK1), as transient transfection of cells with a plasmid encoding a constitutively active form of MEK1 increased MAPK(p42/p44) activity and cell growth, whereas treatment with PD-098059, an inhibitor of MEK1 activity, reduced MAPK(p42/p44) activity and cell growth. Expression of a guanosinetriphosphatase (GTPase)-deficient G alpha(i-2) in these cells increased MAPK(p42/p44) activity and correspondingly reduced cell doubling time from 24 to 10 h without altering the activity of Raf-1 or c-Jun/stress-activated protein kinases (SAPKs). By contrast, expression of a GTPase-deficient G alpha(i-3) in these cells reduced both their cell doubling time by 30% and MAPK(p42/p44) activity by 60%. As the known MEKK isoforms (MEKK1, -2, and -3) can also activate SAPKs, these findings suggest the GTP-charged G alpha(i-2) subunit transduces growth signals in renal cells via activation of MAPK(p42/p44) and that such activation may be linked to pathways containing novel MEKK isoforms that preferentially activate MEKs.

scholarly journals ANTAGONISM BY DIBUTYRYL ADENOSINE CYCLIC 3',5'-MONOPHOSPHATE AND TESTOSTERONE OF CELL ROUNDING REACTIONS

1973 ◽  
Vol 59 (2) ◽  
pp. 471-479 ◽  
Author(s):  
Brian Storrie
Keyword(s):  
Growth Rate ◽  
Protein Synthesis ◽  
Cell Growth ◽  
Concanavalin A ◽  
Divalent Cations ◽  
Cell Growth Rate ◽  
Dibutyryl Camp ◽  
Cell Rounding ◽  
Drug Removal ◽  
Kinetics Of

In an attempt to understand further the mechanism of the morphological and functional "reverse transformation" of CHO-K1 cells induced by dibutyryl adenosine cyclic 3',5'-monophosphate (cAMP) and testosterone, the kinetics of variation in the susceptibility of cells to rounding after the addition or deletion of dibutyryl cAMP and testosterone have been investigated. Changes in susceptibility to cell rounding upon removal of divalent cations or pulse exposure to concanavalin A were complete within 0.5–1 h after addition or deletion of drug. In comparison, the gross conversion of CHO-K1 cells from epithelial- to fibroblast-like morphology after drug treatment or the converse change after drug removal required 8 or 4 h, respectively. The effects on cell rounding are not caused by an effect of dibutyryl cAMP upon cell growth rate. Inhibitor experiments indicate that the changes investigated do not require continued RNA or protein synthesis and are not prevented by agents which depolymerize microtubules.

Sign in / Sign up

Export Citation Format

Share Document