scholarly journals Receptors linked to polyphosphoinositide hydrolysis stimulate Ca2+ extrusion by a phospholipase C-independent mechanism

1999 ◽  
Vol 342 (1) ◽  
pp. 199-206 ◽  
Author(s):  
Lisa M. BROAD ◽  
Toby R. CANNON ◽  
Alison D. SHORT ◽  
Colin W. TAYLOR
Keyword(s):  
Plasma Membrane ◽  
Tyrosine Kinase ◽  
Phospholipase C ◽  
Protein Tyrosine Kinase ◽  
Kinase Activity ◽  
Tyrosine Kinase Activity ◽  
Kinase C ◽  
A7r5 Cells ◽  
Independent Mechanism ◽  
A7r5 Cell Line

In A7r5 cells with empty intracellular Ca2+ stores in which the cytosolic free Ca2+ concentration ([Ca2+]i) had been increased by capacitative Ca2+ entry, stimulation of receptors linked to phospholipase C (PLC), including those for Arg8-vasopressin (AVP) and platelet-derived growth factor (PDGF), caused a decrease in [Ca2+]i. This effect was further examined in a stable variant of the A7r5 cell line in which the usual ability of hormones to stimulate non-capacitative Ca2+ entry is not expresssed. In thapsigargin-treated cells, neither AVP nor PDGF affected capacitative Mn2+ or Ba2+ entry, but both stimulated the rate of Ca2+ extrusion, and their abilities to decrease [Ca2+]i were only partially inhibited by removal of extracellular Na+. These results suggest that receptors linked to PLC also stimulate plasma membrane Ca2+ pumps. Activation of protein kinase C by phorbol 12,13-dibutyrate (PDBu, 1 μM) also caused a decrease in [Ca2+]i by accelerating Ca2+ removal from the cytosol; the effect was again only partially inhibited by removal of extracellular Na+. An inhibitor of PKC, Ro31-8220 (10 μM), abolished the ability of PDBu to decrease [Ca2+]i,without affecting the response to maximal or submaximal concentrations of AVP. Similar experiments with PDGF were impracticable because Ro31-8220, presumably by inhibiting the tyrosine kinase activity of the PDGF receptor, abolished all responses to PDGF. U73122 (10 μM), an inhibitor of PLC, completely inhibited PDGF- or AVP-evoked Ca2+ mobilization, without preventing either stimulus from causing a decrease in [Ca2+]i. We conclude that receptors coupled to PLC, whether via G-proteins or protein tyrosine kinase activity, also share an ability to stimulate the plasma membrane Ca2+ pump via a mechanism that does not require PLC activity.

scholarly journals Platelet-derived growth factor induces multisite phosphorylation of pp60c-src and increases its protein-tyrosine kinase activity.

1988 ◽  
Vol 8 (8) ◽  
pp. 3345-3356 ◽  
Author(s):  
K L Gould ◽  
T Hunter
Keyword(s):  
Protein Kinase C ◽  
Growth Factor ◽  
Protein Kinase ◽  
Tyrosine Kinase ◽  
Protein Tyrosine Kinase ◽  
Kinase Activity ◽  
Platelet Derived Growth Factor ◽  
Tyrosine Kinase Activity ◽  
Kinase C ◽  
Protein Tyrosine Kinase Activity

We have shown previously that pp60c-src is a substrate for protein kinase C in vivo and that the target of protein kinase C phosphorylation in mammalian pp60c-src is serine 12. We now demonstrate that in addition to tumor promoters, all activators of phosphatidylinositol turnover that we have tested in fibroblasts (platelet-derived growth factor, fibroblast growth factor, serum, vasopressin, sodium orthovanadate, and prostaglandin F2 alpha) lead to the phosphorylation of pp60c-src at serine 12. In addition to stimulating serine 12 phosphorylation in pp60c-src, platelet-derived growth factor treatment of quiescent fibroblasts induces phosphorylation of one or two additional serine residues and one tyrosine residue within the N-terminal 16 kilodaltons of the enzyme and activates its immune complex protein-tyrosine kinase activity.

Platelet-derived growth factor induces multisite phosphorylation of pp60c-src and increases its protein-tyrosine kinase activity

1988 ◽  
Vol 8 (8) ◽  
pp. 3345-3356
Author(s):  
K L Gould ◽  
T Hunter
Keyword(s):  
Protein Kinase C ◽  
Growth Factor ◽  
Protein Kinase ◽  
Tyrosine Kinase ◽  
Protein Tyrosine Kinase ◽  
Kinase Activity ◽  
Platelet Derived Growth Factor ◽  
Tyrosine Kinase Activity ◽  
Kinase C ◽  
Protein Tyrosine Kinase Activity

We have shown previously that pp60c-src is a substrate for protein kinase C in vivo and that the target of protein kinase C phosphorylation in mammalian pp60c-src is serine 12. We now demonstrate that in addition to tumor promoters, all activators of phosphatidylinositol turnover that we have tested in fibroblasts (platelet-derived growth factor, fibroblast growth factor, serum, vasopressin, sodium orthovanadate, and prostaglandin F2 alpha) lead to the phosphorylation of pp60c-src at serine 12. In addition to stimulating serine 12 phosphorylation in pp60c-src, platelet-derived growth factor treatment of quiescent fibroblasts induces phosphorylation of one or two additional serine residues and one tyrosine residue within the N-terminal 16 kilodaltons of the enzyme and activates its immune complex protein-tyrosine kinase activity.

scholarly journals Development of the Sensing Platform for Protein Tyrosine Kinase Activity

Biosensors ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 240
Author(s):  
Lan-Yi Wei ◽  
Wei Lin ◽  
Bey-Fen Leo ◽  
Lik-Voon Kiew ◽  
Chia-Ching Chang ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Kinases ◽  
Protein Tyrosine Kinase ◽  
Kinase Activity ◽  
Significant Inhibition ◽  
Tyrosine Kinase Activity ◽  
Protein Tyrosine ◽  
Sensing Platform ◽  
Relative Standard ◽  
Protein Tyrosine Kinase Activity

A miniature tyrosinase-based electrochemical sensing platform for label-free detection of protein tyrosine kinase activity was developed in this study. The developed miniature sensing platform can detect the substrate peptides for tyrosine kinases, such as c-Src, Hck and Her2, in a low sample volume (1–2 μL). The developed sensing platform exhibited a high reproducibility for repetitive measurement with an RSD (relative standard deviation) of 6.6%. The developed sensing platform can detect the Hck and Her2 in a linear range of 1–200 U/mL with the detection limit of 1 U/mL. The sensing platform was also effective in assessing the specificity and efficacies of the inhibitors for protein tyrosine kinases. This is demonstrated by the detection of significant inhibition of Hck (~88.1%, but not Her2) by the Src inhibitor 1, an inhibitor for Src family kinases, as well as the significant inhibition of Her2 (~91%, but not Hck) by CP-724714 through the platform. These results suggest the potential of the developed miniature sensing platform as an effective tool for detecting different protein tyrosine kinase activity and for accessing the inhibitory effect of various inhibitors to these kinases.

Sign in / Sign up

Export Citation Format

Share Document