Lifespan regulation of conventional protein kinase C isotypes

2007 ◽  
Vol 35 (5) ◽  
pp. 1043-1045 ◽  
Author(s):  
D. Carmena ◽  
A. Sardini
Keyword(s):  
Signal Transduction ◽  
Plasma Membrane ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Second Messengers ◽  
Therapeutic Strategies ◽  
Kinase C ◽  
Signalling Network ◽  
Pkc Protein Kinase C ◽  
Lifespan Regulation

Plasma membrane translocation, following allosteric binding of second messengers, initiates the signal transduction process mediated by cPKC [conventional PKC (protein kinase C)] isotypes. Mechanisms regulating the lifespan of the active enzyme such as its phosphorylation, internalization, dephosphorylation and degradation are key elements of the signalling network. The understanding of such mechanisms is essential for the design of therapeutic strategies targeting PKC isoenzymes.

Inositol trisphosphate and diacylglycerol as intracellular second messengers in liver

1985 ◽  
Vol 248 (3) ◽  
pp. C203-C216 ◽  
Author(s):  
J. R. Williamson ◽  
R. H. Cooper ◽  
S. K. Joseph ◽  
A. P. Thomas
Keyword(s):  
Plasma Membrane ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Second Messengers ◽  
Receptor Occupancy ◽  
Water Soluble ◽  
Secretory Cells ◽  
Adrenergic Agents ◽  
Kinase C ◽  
Water Soluble Compound

Receptor occupation by a variety of Ca2+-mobilizing hormones, such as alpha 1-adrenergic agents, vasopressin and angiotensin II, causes a rapid phosphodiesterase-mediated hydrolysis of phosphatidylinositol-4,5-bisphosphate in the plasma membrane with the production of the water soluble compound myo-inositol-1,4,5-trisphosphate (IP3) and the lipophilic molecule 1,2-diacylglycerol (DG). This review summarizes the recent evidence obtained in the liver that defines the roles of these products as intracellular messengers of hormone action. Intracellular Ca2+ mobilization is mediated by IP3, which releases Ca2+ from a subpopulation of the endoplasmic reticulum, resulting in a rapid increase of the cytosolic free Ca2+ concentration ( [Ca2+]i). Further effects of receptor occupancy are inhibition of the plasma membrane Ca2+-ATPase, despite net Ca2+ efflux, and an increased permeability of the plasma membrane to extracellular Ca2+. The activation of the phospholipid-dependent protein kinase C by DG does not alter Ca2+ fluxes across the plasma membrane. In contrast to some secretory cells, a synergism between protein kinase C activation and increased [Ca2+]i is not observed in liver. Activation of protein kinase C profoundly inhibits the response to alpha 1-adrenergic agonists, with only minimal effects on the vasopressin response. It is concluded that in liver the two inositol-lipid messenger systems, IP3 and DG, exert their effects by essentially separate pathways.

scholarly journals PKC-Mediated ZYG1 Phosphorylation Induces Fusion of Myoblasts as well as ofDictyosteliumCells

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Aiko Amagai ◽  
Harry MacWilliams ◽  
Takahiro Isono ◽  
Mariko Omatsu-Kanbe ◽  
Shinya Urano ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Cell Fusion ◽  
Signal Transduction Pathways ◽  
Zygote Formation ◽  
Kinase C ◽  
Pkc Protein Kinase C ◽  
The Difference ◽  
Novel Protein

We have previously demonstrated that a novel protein ZYG1 induces sexual cell fusion (zygote formation) ofDictyosteliumcells. In the process of cell fusion, involvements of signal transduction pathways via Ca2+and PKC (protein kinase C) have been suggested because zygote formation is greatly enhanced by PKC activators. In fact, there are several deduced sites phosphorylated by PKC in ZYG1 protein. Thereupon, we designed the present work to examine whether or not ZYG1 is actually phosphorylated by PKC and localized at the regions of cell-cell contacts where cell fusion occurs. These were ascertained, suggesting that ZYG1 might be the target protein for PKC. A humanized version ofzyg1cDNA (mzyg1) was introduced into myoblasts to know if ZYG1 is also effective in cell fusion of myoblasts. Quite interestingly, enforced expression of ZYG1 in myoblasts was found to induce markedly their cell fusion, thus strongly suggesting the existence of a common signaling pathway for cell fusion beyond the difference of species.

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