Possible role of Na+ influx in phorbol ester-induced down-regulation of protein kinase C in HL60 cells

FEBS Letters ◽  
1993 ◽  
Vol 328 (3) ◽  
pp. 280-284 ◽  
Author(s):  
Noriko Takeuchi ◽  
Eikichi Hashimoto ◽  
Toru Nakamura ◽  
Fumito Takeuchi ◽  
Kiyonao Sada ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Phorbol Ester ◽  
Down Regulation ◽  
Hl60 Cells ◽  
Kinase C

scholarly journals Abnormal protein kinase C down regulation and reduced substrate levels in non-phorbol ester-responsive 3T3-TNR9 cells.

1990 ◽  
Vol 10 (5) ◽  
pp. 2122-2132 ◽  
Author(s):  
H P Biemann ◽  
R L Erikson
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Phorbol Ester ◽  
Kinase Activity ◽  
Subcellular Location ◽  
Parental Cell ◽  
Down Regulation ◽  
Kinase C ◽  
Cell Variant ◽  
Swiss 3T3 Cell

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.

The role of protein kinase C in GH secretion induced by GH-releasing factor and GH-releasing peptides in cultured ovine somatotrophs

1997 ◽  
Vol 154 (2) ◽  
pp. 219-230 ◽  
Author(s):  
D Wu ◽  
I J Clarke ◽  
C Chen
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Dependent Manner ◽  
Adenylyl Cyclase Activity ◽  
Down Regulation ◽  
Gh Secretion ◽  
Calphostin C ◽  
Kinase C ◽  
Pka Pathway

Abstract The involvement of protein kinase C (PKC) in the action of GH-releasing factor (GRF) and synthetic GH-releasing peptides (GHRP-2 and GHRP-6) was investigated in ovine somatotrophs in primary culture. In partially purified sheep somatotrophs, GRF and GHRP-2 caused translocation of PKC activity from the cytosol to the cell membranes and caused GH release in a dose- and time-dependent manner. GHRP-6 did not cause PKC translocation. The PKC inhibitors, calphostin C, staurosporine and chelerythrine, partially reduced GH release in response to GRF and GHRP-2 at doses which selectively inhibit PKC activity. These inhibitors totally abolished GH release caused by phorbol 12-myristate 13-acetate (PMA). Down-regulation of PKC by the treatment of cells with phorbol 12,13-dibutyrate for 16 h caused a significant (P<0·001) reduction in total PKC activity and totally abolished PKC translocation in response to a challenge with GRF, GHRP-2 or PMA. In addition, down-regulation abolished GH release in response to GRF, GHRP-2 or GHRP-6. Treatment of cells with H89, a selective PKA inhibitor, totally blocked GH release caused by either GRF or GHRP-2 and partially reduced PMA-induced GH release. H89 had no effect on PKC translocation caused by GRF, GHRP-2 or PMA and did not affect GH release caused by GHRP-6. These data suggest that GHRP-2 and GRF activate PKC in addition to stimulating adenylyl cyclase activity. Although the cAMP–protein kinase A (PKA) pathway is the major signalling pathway employed by GRF and GHRP-2, the activation of PKC may potentiate signalling via the cAMP–PKA pathway in ovine GH secretion. Importantly, the effect of PMA in increasing the secretion of GH from ovine somatotrophs is effected, in part, by up-regulation of the cAMP–PKA pathway. We conclude that there is cross-talk between the PKC pathway and the cAMP–PKA pathway in ovine somatotrophs during the action of GRF or GHRP. Journal of Endocrinology (1997) 154, 219–230

Induction of protein kinase C down-regulation by the phorbol ester TPA in a calpain/protein kinase C complex

1992 ◽  
Vol 52 (3) ◽  
pp. 399-403 ◽  
Author(s):  
Michel Savart ◽  
Pascale Letard ◽  
Sandrine Bultel ◽  
Andre Ducastaing
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Phorbol Ester ◽  
Down Regulation ◽  
Kinase C ◽  
C Complex

2-Chloroadenosine prevents phorbol ester-induced depletion of protein kinase C in porcine coronary artery

1993 ◽  
Vol 264 (5) ◽  
pp. H1465-H1471 ◽  
Author(s):  
R. B. Marala ◽  
K. Ways ◽  
S. J. Mustafa
Keyword(s):  
Protein Kinase C ◽  
Coronary Artery ◽  
Protein Kinase ◽  
Phorbol Ester ◽  
Chronic Exposure ◽  
Porcine Coronary Artery ◽  
Kinase C ◽  
Adenosine Analogue ◽  
Presence And Absence

In this study we investigated the role of the adenosine analogue 2-chloroadenosine (CAD) in the regulation of protein kinase C (PKC) in porcine coronary artery. Arterial rings were contracted with endothelin-1 (ET-1; 10(-10) to 10(-7) M) and phorbol 12,13-dibutyrate (PDBu; 10(-7) M) after incubating them for 1 and 2 days with PDBu (200 nM) in the presence and absence of CAD (10(-4) M). Chronic exposure to PDBu alone attenuated ET-1-induced contractions, while inclusion of CAD during incubation protected against the PDBu-induced blunting of ET-1-induced contraction. Similarly, PDBu (10(-7) M)-induced contraction of the arterial rings was attenuated upon chronic incubation with PDBu, and once again, inclusion of CAD showed an improved response to PDBu-induced contraction when compared with PDBu alone. Incubation with PDBu (200 nM) for 20 min caused the PKC translocation from cytosol to membrane, whereas CAD totally blocked this translocation. Chronic (1 and 2 days) incubation with PDBu caused a substantial depletion of PKC activities in cytosol and membrane. The presence of CAD protected the PDBu-induced depletion of PKC in both cytosol and membrane. To replete PKC, after incubation with the drugs, the arteries were incubated in the absence of drugs for another 2 days. Arteries incubated with PDBu in the presence and absence of CAD recovered significantly in their response to ET-1 as well as PDBu. These results indicate that CAD protects against the PDBu-induced activation and depletion of PKC in porcine coronary artery.

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