CK1δ kinase activity is modulated by protein kinase C α (PKCα)-mediated site-specific phosphorylation

Amino Acids ◽  
2016 ◽  
Vol 48 (5) ◽  
pp. 1185-1197 ◽  
Author(s):  
Zhigang Meng ◽  
Joachim Bischof ◽  
Chiara Ianes ◽  
Doris Henne-Bruns ◽  
Pengfei Xu ◽  
...  
Biomedicines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 45
Author(s):  
Suresh Velnati ◽  
Sara Centonze ◽  
Federico Girivetto ◽  
Daniela Capello ◽  
Ricardo M. Biondi ◽  
...  

PKCζ and PKCι/λ form the atypical protein kinase C subgroup, characterised by a lack of regulation by calcium and the neutral lipid diacylglycerol. To better understand the regulation of these kinases, we systematically explored their interactions with various purified phospholipids using the lipid overlay assays, followed by kinase activity assays to evaluate the lipid effects on their enzymatic activity. We observed that both PKCζ and PKCι interact with phosphatidic acid and phosphatidylserine. Conversely, PKCι is unique in binding also to phosphatidylinositol-monophosphates (e.g., phosphatidylinositol 3-phosphate, 4-phosphate, and 5-phosphate). Moreover, we observed that phosphatidylinositol 4-phosphate specifically activates PKCι, while both isoforms are responsive to phosphatidic acid and phosphatidylserine. Overall, our results suggest that atypical Protein kinase C (PKC) localisation and activity are regulated by membrane lipids distinct from those involved in conventional PKCs and unveil a specific regulation of PKCι by phosphatidylinositol-monophosphates.


1990 ◽  
Vol 10 (5) ◽  
pp. 2122-2132 ◽  
Author(s):  
H P Biemann ◽  
R L Erikson

The cell line TNR9 (E. Butler-Gralla and H. R. Herschman, J. Cell. Physiol. 107:59-67, 1981) in a Swiss 3T3 cell variant that expresses protein kinase C (PKC) but is mitogenically nonresponsive to the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA). We have found that PKCs purified from variant and parental cells are identical as judged by kinase activity, protease mapping, and column chromatography. We analyzed cellular levels and subcellular location of PKC in TPA-treated 3T3 and TNR9 cells via immunoprecipitation of [35S]methionine-labeled protein and assay of immune-complex PKC kinase activity. TNR9 cells grew to higher densities than parental 3T3 cells. TNR9 cells at maximal density did not down regulate PKC in response to long-term TPA treatment. We compared the 80-kilodalton (kDa) PKC substrate phosphorylation in 3T3 and TNR9 cells by using two-dimensional gels and found that TNR9 cells treated with TPA for 30 min contained only 10 to 15% as much 32Pi associated with the 80-kDa as did parental cells. The TNR9 80-kDa substrate was present at reduced levels compared with the parental-cell 80-kDa substrate as judged by immunoblot and silver staining. Thus, the loss of mitogenic responsiveness to TPA in TNR9 cells is accompanied by resistance to TPA-mediated down regulation of PKC and reduced phosphosubstrate levels.


2005 ◽  
Vol 33 (6) ◽  
pp. 1341-1344 ◽  
Author(s):  
A. Morgan ◽  
R.D. Burgoyne ◽  
J.W. Barclay ◽  
T.J. Craig ◽  
G.R. Prescott ◽  
...  

PKC (protein kinase C) has been known for many years to modulate regulated exocytosis in a wide variety of cell types. In neurons and neuroendocrine cells, PKC regulates several different stages of the exocytotic process, suggesting that these multiple actions of PKC are mediated by phosphorylation of distinct protein targets. In recent years, a variety of exocytotic proteins have been identified as PKC substrates, the best characterized of which are SNAP-25 (25 kDa synaptosome-associated protein) and Munc18. In the present study, we review recent evidence suggesting that site-specific phosphorylation of SNAP-25 and Munc18 by PKC regulates distinct stages of exocytosis.


1989 ◽  
Vol 260 (2) ◽  
pp. 499-507 ◽  
Author(s):  
G E Kass ◽  
S K Duddy ◽  
S Orrenius

The effects of quinone-generated active oxygen species on rat hepatocyte protein kinase C were investigated. The specific activity of cytosolic protein kinase C was increased 2-3-fold in hepatocytes incubated with the redox-cycling quinones, menadione, duroquinone or 2,3-dimethoxy-1,4-naphthoquinone, without alterations in particulate protein kinase C specific activity or Ca2+- and lipid-independent kinase activities. Redox-cycling quinones did not stimulate translocation of protein kinase C; however, activated protein kinase C was redistributed from cytosol to the particulate fraction when quinone-treated hepatocytes were exposed to 12-O-tetradecanoylphorbol 13-acetate (TPA). Quinone treatment did not alter cytosolic phorbol 12,13-dibutyrate (PDBu) binding capacity, and the cytosol of both control and quinone-treated hepatocytes exhibited a Kd for PDBu binding of 2 nM. Quinone-mediated activation of cytosolic protein kinase C was reversed by incubation with 10 mM-beta-mercaptoethanol, dithiothreitol or GSH, at 4 degrees C for 24 h. Furthermore, protein kinase C specific activity in control cytosol incubated in air increased by over 100% within 3 h; this increase was reversed by thiol-reducing agents. Similarly, incubation of partially-purified rat brain protein kinase C in air, or with low concentrations of GSSG in the presence of GSH, resulted in a 2-2.5-fold increase in Ca2+- and lipid-dependent kinase activity. In contrast with the effects of the redox-cycling quinones, when hepatocytes were treated with the thiol agents N-ethylmaleimide (NEM), p-benzoquinone (pBQ) or p-chloromercuribenzoic acid (pCMB), the cytosolic Ca2+- and lipid-dependent kinase activity was significantly inhibited, but the particulate-associated protein kinase C activity was unaffected. The Ca2+- and lipid-independent kinase activity of both the cytosolic and particulate fractions was significantly stimulated by NEM, but was unaffected by pBQ and pCMB. These results show that hepatocyte cytosolic protein kinase C is activated to a high-Vmax form by quinone-generated active oxygen species, and this effect is due to a reduction-sensitive modification of the thiol/disulphide status of protein kinase C.


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