Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.13 (protein kinase C)
 49,245 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Interleukin (IL)-1 has been shown to be a potent inhibitor of hair growth in vitro. We hypothesized that this cytokine might be a decisive factor causing hair loss during the lymphocytic attack in alopecia areata. Neither the intracellular pathways involved in hair growth inhibition mediated by IL-1beta nor the signal transduction processes within hair follicles in general are known. We therefore investigated the intracellular signals involved in human hair growth in vitro. Hair follicles were isolated from scalp biopsies by microdissection, and hair growth was measured daily by image analysis. We assessed intracellular signal transducing elements using specific inhibitors or activators either alone or in combination with IL-1beta. The calcium ionophore A 23187 induced a rapid and complete arrest of hair growth, and phorbol-12-myristate-13-acetate (PMA), genistein, or IL-1beta decreased hair growth by approximately 60%-80%. IL-1beta-elicited hair growth arrest was not antagonized by calphostin C, a specific inhibitor of protein kinase C. In contrast, coincubation of IL-1beta with pertussis toxin or H 1004 neutralized the effect of IL-1beta, and dibutyryl-cAMP and cholera toxin, an activator of adenylate cyclase, inhibited hair growth. These data suggest that cAMP acts as a second messenger for IL-1beta-induced inhibition of hair growth. Moreover, our data indicate that in vitro hair growth is dependent on intracellular Ca2+ levels and activation of tyrosine kinase as well as protein kinase C. We were unable to detect a signal transducing element responsible for enhanced hair growth in vitro.
J Invest Dermatol 1997 Jan
PMID:Interleukin-1beta-induced inhibition of hair growth in vitro is mediated by cyclic AMP. 898 Feb 84

We investigated the regulation of C3 production by human cultured epidermal keratinocytes by enzyme-linked immunosorbent assay. The results showed that IFNgamma and TNFalpha enhanced the synthesis of C3 by epidermal keratinocytes in a concentration-dependent manner. Moreover, a protein kinase C (PKC) inhibitor blocked C3 production, whereas PMA enhanced it. There was a synergistic effect between IFNgamma and TNFalpha. In experiments to investigate the role of protein tyrosine kinase (PTK) in C3 production, we found that treatment with herbimycin A, a specific inhibitor for the c-Src-related PTK, caused significant enhancement of the C3 production induced by IFNgamma or TNFalpha, suggesting that c-Src-type PTK(s) provides a negative signal to C3 production. Each competitive inhibitor of PTK, genistein or tyrphostin, substantially increased the C3 production by IFNgamma at lower concentrations, although each agent had little effect on TNFalpha-associated production of C3 at the same concentrations. The data show that pro-inflammatory cytokines IFNgamma and TNFalpha synergistically augment C3 production by epidermal keratinocytes by different pathways.
J Invest Dermatol 1997 Jan
PMID:C3 production of cultured human epidermal keratinocytes is enhanced by IFNgamma and TNFalpha through different pathways. 898 Feb 89

We have demonstrated previously that pemphigus vulgaris (PV)-IgG induces activation of phospholipase C (PLC), production of inositol 1,4,5-trisphosphate, and a rapid transient increase in [Ca2+]i in cultured human keratinocytes, leading to secretion of plasminogen activator and cell-cell detachment in cell culture. In the current study, to examine the involvement of protein kinase C (PKC) in the mechanism of blister formation in PV, we studied the PV-IgG-induced translocation of PKC isozymes from the cytosol to the particulate/cytoskeleton (p/c) fractions and the activation of PKC in human keratinocytes. Cells cultured in Eagle's minimum essential medium were incubated with PV-IgGs for 30 s, 1 min, 5 min, or 30 min. PV-IgG binding to the cell surface antigen (desmoglein III) induced translocation of PKC-alpha from the cytosol to the p/c fractions within 30 s, with a peak at 1 min that lasted at least 30 min. PKC-delta also was translocated within 1 min and reached a peak at 5 min but was reduced to basal levels at 30 min. Alternatively, PKC-eta translocation to the p/c fraction was induced slowly, taking more than 5 min, and was reduced to approximately half-maximum at 30 min, whereas PKC-zeta translocation reached a maximum at 30 s, rapidly returning to baseline by 5 min after PV-IgG stimulation. The total PKC activity in the p/c fraction also was increased after PV-IgG exposure, peaked at 1 min, and was sustained for at least 30 min. These findings suggest that a unique activation profile of PKC isomers may be involved in mediating the intracellular signaling events induced by PV-IgG binding to desmoglein III in cultured human keratinocytes.
J Invest Dermatol 1997 Apr
PMID:Pemphigus IgG activates and translocates protein kinase C from the cytosol to the particulate/cytoskeleton fractions in human keratinocytes. 907 78

Epidermal keratinocytes express beta 2-adrenergic receptors on the cell membrane. The binding of the agonists to the beta 2-adrenergic receptors regulates activation of adenylate cyclase. This transmembrane signaling system has been regarded to be one of the important pathways for the functions of keratinocytes. We previously reported that beta-adrenergic stimulation induced a transient increase of intracellular Ca2+ in normal human epidermal keratinocytes. Thus we investigated the effects of epinephrine on another transmembrane signaling system, the phosphatidyl-inositol signal transduction pathway in pig epidermis. Treatment of pig pure epidermis with epinephrine resulted in a transient increase in inositol 1,4,5-trisphosphate with a peak at 30 s. Epinephrine induced translocation of protein kinase C from cytosol to the membrane fraction. The activation of protein kinase C, translocation of protein kinase C from cytosol to the membrane fraction, was confirmed using the beta-adrenergic agonist isoproterenol. Moreover, the effect of epinephrine on the activation of protein kinase C was inhibited by preincubation with propranolol, a beta-adrenergic antagonist. The increase in inositol 1,4,5-trisphosphate and translocation of protein kinase C by epinephrine are consistent with the view that beta-adrenergic stimulation induces turnover of inositol phospholipid in pig epidermis.
Exp Dermatol 1997 Jun
PMID:beta-Adrenergic stimulation induces activation of protein kinase C and inositol 1,4,5-trisphosphate increase in epidermis. 922 35

Interferon gamma (IFN-gamma) is a potent inducer of cell growth arrest in human epidermal keratinocytes. Interferon regulatory factor-1 (IRF-1), an interferon-inducible gene, is a mediator of interferon action. It has also been suggested that IRF-1 may have a functional role as a tumor suppressor gene and may be associated with the antiproliferative effect of IFN-gamma. We examined the expression of IRF-1 mRNA in normal human epidermal keratinocytes (NHEK). Northern blot analysis demonstrated an increased expression of IRF-1 mRNA by IFN-gamma in NHEKs. This increased expression of IRF-1 mRNA by IFN-gamma was not blocked by treatment with cycloheximide, but was abolished by treatment with actinomycin D. In addition, neither pretreatment with TPA, a protein kinase C (PKC) activator, nor treatment with H7, a PKC inhibitor, affected the induction of IRF-1 mRNA by IFN-gamma. These results indicate that IFN-gamma-induced IRF-1 mRNA in NHEKs is transcriptional and PKC-independent.
Arch Dermatol Res 1997 Jun
PMID:IRF-1 expression in normal human epidermal keratinocytes. 924 21

Fas is a well-known cell surface receptor whose main function is the induction of apoptosis in many cell types including human keratinocytes. Several reports indicate that anti-Fas antibody can induce apoptosis in cultured keratinocytes after interferon gamma (IFN gamma) pretreatment. Because IFN gamma is synthesized by activated T cells, but not by keratinocytes, these results suggest that Fas may only be effective in apoptosis occurring in T-cell mediated inflammatory skin diseases. We hypothesized that Fas alone might mediate apoptosis in normal human keratinocytes without any other help and thus play a role in normal epidermal homeostasis. By using Cell Death Detection ELISA, we observed keratinocyte apoptosis 24 hours after anti-Fas antibody stimulation not only in IFN gamma-pretreated conditions but also in non-pretreated conditions. Even though the percentage of cultured keratinocytes stained by anti-Fas antibody increased from 7.8 to 25.8% 24 hours after IFN gamma stimulation, the apoptotic rate of the anti-Fas only group was the same as that of the anti-Fas plus IFN gamma treated group. In both conditions, we have verified apoptotic phenomena in cultured keratinocytes in situ by TUNEL staining. Some apoptotic bodies were phagocytosed by neighboring keratinocytes. Fas-mediated apoptosis was not inhibited by the protein synthesis inhibitor cycloheximide and was enhanced by inhibitors of several protein kinases, including PKC and staurosporine. These results suggest that Fas-mediated apoptosis may play a role in both T cell-mediated skin diseases and normal epidermal homeostasis.
J Dermatol 1997 Jul
PMID:Apoptosis is induced by anti-Fas antibody alone in cultured human keratinocytes. 926 2

Different chemicals that specifically and selectively inhibit or activate protein kinases have been used to define the possible roles of these enzymes in the different steps of epidermal differentiation. Using HaCaT keratinocytes as a model, and under conditions in which cell proliferation is minimally affected, we found that tyrosine kinase inhibition leads to an inhibition of early (spinous; keratin k10 expression) and late (granulosum; involucrin expression) differentiation processes. cGMP- and cAMP-dependent protein kinases appear to modulate the transition from spinous to granular differentiation, a process which seems to be negatively controlled by protein phosphatases. Finally, enzymes belonging to the protein kinase C family appear to facilitate the transition from spinous to granular differentiation programmes while inhibiting the early steps of epidermal differentiation.
Br J Dermatol 1997 Jul
PMID:Role of protein kinases in the in vitro differentiation of human epidermal HaCaT cells. 927 24

Monomethylfumarate (MMF), the most active metabolite of the new antipsoriasis drug Fumaderm, stimulates an anti-inflammatory mediator profile in human leucocytes and inhibits the proliferation of keratinocytes. These effects of MMF on cells in vitro may in part explain the beneficial action of Fumaderm in patients. In addition, we have reported that MMF stimulates an increase in the intracellular free Ca2+ concentration ([Ca2+]i) and the cyclic adenosine monophosphate (cAMP) concentration in granulocytes and keratinocytes. Because Ca2+ and cAMP control many physiological cellular responses, including cell proliferation and inflammatory mediator production, the present study focused on the intracellular signal transduction pathway which links interaction between MMF and granulocytes with increases in [Ca2+]i and the cAMP concentration. The increase in [Ca2+]i in granulocytes after MMF depended both on extracellular Ca2+ and Ca2+ from intracellular stores. Ca2+ is essential for the increase in the cAMP concentration after stimulation with MMF. The results found for pharmacological inhibitors of various protein kinases suggest that a staurosporine-sensitive protein kinase different from protein kinase C (PKC) and protein kinase A is involved in the MMF-induced increase in [Ca2+]i in granulocytes. As MMF activated protein tyrosine kinase (PTK), and inhibition of this protein kinase partially reduced the increase in [Ca2+]i in granulocytes, PTK activity most likely is involved. In addition, activation of protein kinase histone 4 (PKH4) probably plays a part in the MMF-stimulated increase in [Ca2+]i in granulocytes as well. As MMF stimulated an increase in the GTP-ase activity of membranes and pertussis toxin (PTX) inhibited the increase in the [Ca2+]i and PKH4 activity of granulocytes stimulated by this compound, it is concluded that MMF activates PTX-sensitive G proteins. Competition binding studies with radiolabelled dimethylfumarate (DMF) and unlabelled DMF and MMF revealed the presence of specific binding sites for methylated fumarates on granulocytes. In summary, MMF binds to specific sites on the plasma membrane of cells. This interaction activates pertussis toxin-sensitive G proteins which then stimulate an increase in PTK and PKH4 activity. These protein kinases may regulate the rise in [Ca2+]i and the intracellular cAMP concentration. Elevated [Ca2+]i and intracellular cAMP concentration stimulate protein kinases that regulate transcription factors. Activation of these factors results in induction of downstream gene expression and thus controls cell functions, e.g. cell proliferation and production of inflammatory mediators, as has been found for cells incubated with MMF.
Br J Dermatol 1997 Jul
PMID:Intracellular signalling by binding sites for the antipsoriatic agent monomethylfumarate on human granulocytes. 927 27

Membrane glycoproteins (gps) play an important role in cell-cell interactions during epidermal maturation, and we have previously shown an up-regulation of PNA-binding gps in cultured human keratinocytes treated with interferon gamma (IFN-gamma). The protein kinase C (PKC) pathway is known to play a key role in the regulation of proliferation and differentiation of keratinocytes and is also reported to be involved in some IFN-gamma-mediated effects. In order to evaluate the cellular mechanisms and whether PNA-binding gp expression is related to the differentiative activity of the lymphokine, we studied the effects of PKC agonists and antagonists and the role of retinoic acid (RA), in the induction of these gps in cultured human keratinocytes stimulated with IFN-gamma and processed for protein analysis. The expression of PNA-binding gps was revealed by incubation of SDS-polyacrylamide gels with 125I-PNA. The PKC antagonists (H7, sphingosine) as well as RA downregulated the IFN-gamma-induced PNA-reactive gps, whereas staurosporine and TPA upregulated their expression. These results provide evidence that PNA-reactive gps are late highly IFN-gamma-sensitive markers of keratinocyte differentiation, drastically modulated through selective isoforms of PKC.
Arch Dermatol Res 1997 Oct
PMID:Interferon gamma-induced PNA-binding glycoproteins as markers of human keratinocyte differentiation: biological evidence using protein kinase C agonists, antagonists and retinoic acid. 944 84

Involucrin is one of the precursor proteins of the cornified cell envelope that is formed beneath the cell membrane during terminal differentiation of keratinocytes. 12-O-tetradecanoylphorbol-13-acetate (TPA), which is a potent protein kinase C (PKC) activator, induces terminal differentiation of keratinocytes. We previously demonstrated that involucrin promoter activity is stimulated by TPA in cultured fetal rat skin keratinocytes. PKC is a large family of proteins and keratinocytes containing five PKC isozymes: alpha, delta, epsilon, eta, and zeta. In order to determine the role of the PKC isozyme(s) on involucrin gene expression, we constructed the chloramphenicol acetyl transferase (CAT)-involucrin promoter expression vector by connecting the 5'-upstream region of the human involucrin gene containing the untranslated first exon to the CAT reporter gene. The CAT-involucrin promoter expression vector was transfected with various PKC isozyme expression vectors into SV40-transformed human keratinocytes (SVHK cells). Transfection of the CAT-involucrin promoter expression vector with PKC-alpha or PKC-eta expression vectors resulted in a significant increase in the TPA-dependent involucrin promoter activity. The PKC inhibitor, 1-(5-isoquinoline-sulfonyl)-2-methyl piperazine dihydrochloride, inhibited the promoter activity stimulated by TPA. Transfection of PKC-delta, -epsilon, and -zeta had no effect on the involucrin-promoter activity. Although the promoter activity was stimulated by transfection of PKC-gamma, TPA did not enhance the promoter activity in the PKC-gamma-transfected SVHK cells. Previously we showed three AP-1 binding sites (AP1-1, -2, and -3) on the involucrin promoter region. Both the basal and the TPA-stimulated involucrin promoter activities were suppressed by deleting the AP1-1 site (-119 to -113) that is the most proximal to the transcription start site. The deletion of AP1-2 (-297 to -303) or AP1-3 (-447 to -453) did not affect the involucrin promoter activity. Gel retardation analyses disclosed that TPA stimulated the specific DNA binding of the nuclear protein(s) of control, PKC-alpha, or PKC-eta-transfected SVHK cells, but not of PKC-gamma-transfected cells. Addition of anti-c-Jun and anti-c-Fos antibodies decreased the specific protein-DNA complex band with a concomitant appearance of supershifted bands. These results indicate that PKC, specifically PKC-alpha and PKC-eta, mediates the TPA-dependent activation of involucrin gene expression of SVHK cells. PKC-gamma, which is not present in keratinocytes, also induces involucrin gene expression in a TPA-independent manner, when introduced into SVHK cells.
J Invest Dermatol 1998 Mar
PMID:The alpha and eta isoforms of protein kinase C stimulate transcription of human involucrin gene. 950 39


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