Proteoglycan synthesis is increased in cells with impaired clathrin-dependent endocytosis

2001 ◽  
Vol 114 (2) ◽  
pp. 335-343 ◽  
Author(s):  
A. Llorente ◽  
K. Prydz ◽  
M. Sprangers ◽  
G. Skretting ◽  
S.O. Kolset ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Mrna Level ◽  
Gel Filtration ◽  
Exchange Chromatography ◽  
Proteoglycan Synthesis ◽  
Kinase C ◽  
Core Proteins ◽  
Sulfate Incorporation ◽  
In Cells

Overexpression of a GTPase deficient dynamin mutant in HeLa dynK44A cells causes a block in clathrin-dependent endocytosis. When endocytosis is inhibited, these cells incorporate higher levels of [(35)S]sulfate into both cellular and secreted macromolecules and larger amounts of proteoglycans such as syndecan and perlecan are immunoprecipitated from [(35)S]sulfate-labelled lysates. Gel filtration and ion-exchange chromatography revealed that the increased [(35)S]sulfate incorporation into proteoglycans was not due to significant differences in size or density of negative charge of glycosaminoglycan chains attached to proteoglycan core proteins. On the other hand, measurements of the syndecan-1 mRNA level and of [(3)H]leucine-labelled perlecan after immunoprecipitation supported the idea that the increased [(35)S]sulfate incorporation into proteoglycans was due to a selective increase in the synthesis of proteoglycan core proteins. Interestingly, the activity of protein kinase C was increased in cells expressing mutant dynamin and inhibition of protein kinase C with BIM reduced the differences in [(35)S]sulfate incorporation between cells with normal and impaired clathrin-dependent endocytosis. Thus, the activation of protein kinase C observed upon inhibition of clathrin-dependent endocytosis may be responsible for the increased synthesis of proteoglycans.

scholarly journals Regulation of heparan sulfate proteoglycan nuclear localization by fibronectin

2001 ◽  
Vol 114 (9) ◽  
pp. 1613-1623 ◽  
Author(s):  
T.P. Richardson ◽  
V. Trinkaus-Randall ◽  
M.A. Nugent
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Heparan Sulfate ◽  
Nuclear Localization ◽  
Laser Scanning Microscopy ◽  
Type I ◽  
Heparin Binding ◽  
Kinase C ◽  
Core Proteins ◽  
In Cells

Heparan sulfate proteoglycans (HSPG) regulate multiple cellular processes and mediate the cellular uptake of numerous molecules. While heparan sulphate glycosaminoglycan chains are known to modulate receptor binding of several heparin-binding proteins, here we show that distinct extracellular matrices direct HSPG to the nucleus. We analyzed HSPG localization in primary corneal fibroblasts, cultured on fibronectin or collagen type I matrices, using confocal laser scanning microscopy and cell fractionation. Image analysis revealed that the nuclear localization of HSPG core proteins was greater when cells were cultured on fibronectin versus collagen. Matrices containing the heparin-binding domain of fibronectin, but not the integrin-activating domain, demonstrated increased nuclear staining of core proteins. Furthermore, activation of protein kinase C with phorbol 12-myristate 13-acetate inhibited nuclear targeting of HSPG in cells on fibronectin, whereas inhibition of protein kinase C with Ro-31-8220 greatly enhanced nuclear localization of HSPG in cells on both collagen and fibronectin. We propose a matrix-dependent mechanism for nuclear localization of cell surface HSPG involving protein kinase C-mediated signaling. Nuclear localization of HSPG might play important roles in regulating nuclear function.

Protein kinase C from chicken gizzard: characterization and detection of an inhibitor and endogenous substrates

1989 ◽  
Vol 67 (6) ◽  
pp. 260-270 ◽  
Author(s):  
Gwyneth DeVries ◽  
Elaine D. Fraser ◽  
Michael P. Walsh
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Gel Filtration ◽  
Hydrophobic Interaction Chromatography ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Chicken Gizzard ◽  
Substrate Protein ◽  
Kinase C ◽  
Endogenous Substrates

Protein kinase C was purified from the cytosolic fraction of chicken gizzard by Ca2+-dependent hydrophobic interaction chromatography, anion-exchange chromatography, and hydrophobic chromatography. The molecular weight was estimated as 61 500 by gel filtration and 80 000 by denaturing gel electrophoresis, indicating that the native enzyme is a monomer. Using the mixed micellar assay, with histone III-S as the substrate, protein kinase C required Ca2+, phospholipid, and diacylglycerol for activity, with half-maximal activation at ~5 × 10−7 M Ca2+ in the presence of L-α-phosphatidyl-L-serine and 1,2-diolein. No activation by Ca2+ was observed in the absence of diacylglycerol. Protein kinase C requires free Mg2+, in addition to the MgATP2− substrate, for activity. The Km for ATP was determined to be 20 μM. Activity was sensitive to ionic strength, with half-maximal inhibition at 70 mM NaCl. Using the liposomal assay, phosphorylation of platelet P47 protein and smooth muscle vinculin was more strongly dependent on Ca2+ and lipids than was histone phosphorylation. Partial digestion of protein kinase C with trypsin yielded a constitutively active fragment. A heat-stable inhibitor and three major endogenous protein substrates of protein kinase C were also detected in chicken gizzard smooth muscle.Key words: protein kinase C, gizzard, inhibitor, endogenous substrates.

scholarly journals Nedd4-2 but not Nedd4-1 is critical for protein kinase C-regulated ubiquitination, expression, and transport activity of human organic anion transporter 1

2016 ◽  
Vol 310 (9) ◽  
pp. F821-F831 ◽  
Author(s):  
Da Xu ◽  
Haoxun Wang ◽  
Qiang Zhang ◽  
Guofeng You
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Cell Surface ◽  
Organic Anion ◽  
The Body ◽  
Organic Anion Transporter ◽  
Transport Activity ◽  
Kinase C ◽  
Anion Transporter ◽  
In Cells

Human organic anion transporter 1 (hOAT1) expressed at the membrane of the kidney proximal tubule cells mediates the body disposition of a diverse array of clinically important drugs, including anti-HIV therapeutics, antitumor drugs, antibiotics, antihypertensives, and antiinflammatories. Therefore, understanding the regulation of hOAT1 will provide significant insights into kidney function and dysfunction. We previously established that hOAT1 transport activity is inhibited by activation of protein kinase C (PKC) through accelerating hOAT1 internalization from cell surface into intracellular endosomes and subsequent degradation. We further established that PKC-induced hOAT1 ubiquitination is an important step preceding hOAT1 internalization. In the current study, we identified two closely related E3 ubiquitin ligases, neural precursor cell expressed, developmentally downregulated 4-1 and 4-2 (Nedd4-1 and Nedd4-2), as important regulators for hOAT1: overexpression of Nedd4-1 or Nedd4-2 enhanced hOAT1 ubiquitination, reduced the hOAT1 amount at the cell surface, and suppressed hOAT1 transport activity. In further exploring the relationship among PKC, Nedd4-1, and Nedd4-2, we discovered that PKC-dependent changes in hOAT1 ubiquitination, expression, and transport activity were significantly blocked in cells transfected with the ligase-dead mutant of Nedd4-2 (Nedd4-2/C821A) or with Nedd4-2-specific siRNA to knockdown endogenous Nedd4-2 but not in cells transfected with the ligase-dead mutant of Nedd4-1 (Nedd4-1/C867S) or with Nedd4-1-specific siRNA to knockdown endogenous Nedd4-1. In conclusion, this is the first demonstration that both Nedd4-1 and Nedd4-2 are important regulators for hOAT1 ubiquitination, expression, and function. Yet they play distinct roles, as Nedd4-2 but not Nedd4-1 is a critical mediator for PKC-regulated hOAT1 ubiquitination, expression, and transport activity.

scholarly journals Protein kinase C isoenzymes in airway smooth muscle

1997 ◽  
Vol 324 (1) ◽  
pp. 167-175 ◽  
Author(s):  
Benjamin L. J. WEBB ◽  
Mark A. LINDSAY ◽  
Peter J. BARNES ◽  
Mark A. GIEMBYCZ
Keyword(s):  
Smooth Muscle ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Oligonucleotide Primer ◽  
Mrna Levels ◽  
Kinase C ◽  
Gf 109203X ◽  
Bona Fide

The protein kinase C (PKC) isoenzymes expressed by bovine tracheal smooth muscle (BTSM) were identified at the protein and mRNA levels. Western immunoblot analyses reliably identified PKCα, PKCβI and PKCβII. In some experiments immunoreactive bands corresponding to PKCδ, PKCϵ and PKCθ were also labelled, whereas the γ, η and ζ isoforms of PKC were never detected. Reverse transcriptase PCR of RNA extracted from BTSM using oligonucleotide primer pairs designed to recognize unique sequences in the PKC genes for which protein was absent or not reproducibly identified by immunoblotting, amplified cDNA fragments that corresponded to the predicted sizes of PKCδ, PKCϵ and PKCζ, which was confirmed by Southern blotting. Anion-exchange chromatography of the soluble fraction of BTSM following homogenization in Ca2+-free buffer resolved two major peaks of activity. Using ϵ-peptide as the substrate, the first peak of activity was dependent upon Ca2+ and 4β-PDBu (PDBu = phorbol 12,13-dibutyrate), and represented a mixture of PKCs α, βI and βII. In contrast, the second peak of activity, which eluted at much higher ionic strength, also appeared to comprise a combination of conventional PKCs that were arbitrarily denoted PKCα′, PKCβI′ and PKCβII′. However, these novel enzymes were cofactor-independent and did not bind [3H]PDBu, but were equally sensitive to the PKC inhibitor GF 109203X compared with bona fide conventional PKCs, and migrated on SDS/polyacrylamide gels as 81 kDa polypeptides. Taken together, these data suggest that PKCs α′, βI′ and βII′ represent modified, but not proteolysed, forms of their respective native enzymes that retain antibody immunoreactivity and sensitivity to PKC inhibitors, but have lost their sensitivity to Ca2+ and PDBu when ϵ-peptide is used as the substrate.

scholarly journals The regulatory domain of protein kinase C delta positively regulates insulin receptor signaling

2009 ◽  
Vol 44 (3) ◽  
pp. 155-169 ◽  
Author(s):  
Avraham I Jacob ◽  
Miriam Horovitz-Fried ◽  
Shlomit Aga-Mizrachi ◽  
Tamar Brutman-Barazani ◽  
Hana Okhrimenko ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Insulin Receptor ◽  
Glycogen Synthase ◽  
Regulatory Domain ◽  
Protein Kinase C Delta ◽  
Kinase C ◽  
Regulatory Effects ◽  
In Cells

Protein kinase C delta (PKCδ) is induced by insulin to rapidly associate with insulin receptor (IR) and upregulates insulin signaling. We utilized specific JM and CT receptor domains and chimeras of PKCα and PKCδ regulatory and catalytic domains to elucidate which components of PKCδ are responsible for positive regulatory effects of PKCδ on IR signaling. Studies were performed on L6 and L8 skeletal muscle myoblasts and myotubes. PKCδ was preferentially bound to the JM domain of IR, and insulin stimulation increased this binding. Both PKCδ/α and PKCα/δ chimeras (regulatory/catalytic) were bound preferentially to the JM but not to the CT domain of IR. Although IR–PKCδ binding was higher in cells expressing either the PKCδ/α or PKCα/δ chimera than in control cells, upregulation of IR signaling was observed only in PKCδ/α cells. Thus, in response to insulin increases in tyrosine phosphorylation of IR and insulin receptor substrate-1, downstream signaling to protein kinase B and glycogen synthase kinase 3 (GSK3) and glucose uptake were greater in cells overexpressing PKCδ/α and the PKCδ/δ domains than in cells expressing the PKCα/δ domains. Basal binding of Src to PKCδ was higher in both PKCδ/α- and PKCα/δ-expressing cells compared to control. Binding of Src to IR was decreased in PKCα/δ cells but remained elevated in the PKCδ/α cells in response to insulin. Finally, insulin increased Src activity in PKCδ/α-expressing cells but decreased it in PKCα/δ-expressing cells. Thus, the regulatory domain of PKCδ via interaction with Src appears to determine the role of PKCδ as a positive regulator of IR signaling in skeletal muscle.

scholarly journals p21WAF1 expression by an activator of protein kinase C is regulated mainly at the post-transcriptional level in cells lacking p53: important role of RNA stabilization

1999 ◽  
Vol 337 (3) ◽  
pp. 607-616 ◽  
Author(s):  
Makoto AKASHI ◽  
Yoshiaki OSAWA ◽  
H. Phillip KOEFFLER ◽  
Misao HACHIYA
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Phorbol Esters ◽  
P53 Protein ◽  
Mitogen Activated Protein Kinase ◽  
Luciferase Reporter ◽  
Transcriptional Level ◽  
Kinase C ◽  
In Cells

p21WAF1 inhibits cyclin–cyclin-dependent kinase (Cdk) complexes, causing cell cycle arrest. p21WAF1 contains p53-binding sites in its promoter and expression of p21WAF1 is induced by functional p53. In the present work, we have studied the role of protein kinase C (PKC) in the induction of p21WAF1 and show that induction of p21WAF1 expression can occur by activation of PKC in cells having no p53. Human ovarian carcinoma cells, SKOV-3, lack p53 protein and PMA, a potent activator of PKC, did not induce p53. PMA increased the expression of p21WAF1 mRNA both in these cells and in other cells which do not contain p53 (THP-1 and U937). Treatment of human embryonic fibroblasts, WI38, with PMA also induced the accumulation of p21WAF1 without affecting p53 levels. However, PMA did not increase levels of p21WAF1 mRNA in cells where either the PKC or the mitogen-activated protein kinase pathway was blocked. Furthermore, treatment of cells with various phorbol ester derivatives which activate PKC resulted in the induction of p21WAF1 in SKOV-3 cells. In contrast, phorbol esters which do not activate PKC failed to induce p21WAF1 expression. PMA increased the transcriptional rate of p21WAF1 and activated the transcription of a luciferase reporter gene, controlled by the p21 promoter, in SKOV-3 cells with or without a p53 consensus-binding sequence. By contrast, PMA markedly stabilized p21WAF1 mRNA; the half-life (t1/2) of p21WAF1 in PMA-treated cells was > 8 h compared with < 1 h in untreated cells. These findings provide evidence that the PKC pathway induces expression of p21WAF1 independently of p53. Our present study also suggests that the accumulation of p21WAF1 transcripts by PMA occurs mainly at post-transcriptional level.

scholarly journals Microtubule depolymerization activates the Epstein–Barr virus lytic cycle through protein kinase C pathways in nasopharyngeal carcinoma cells

2013 ◽  
Vol 94 (12) ◽  
pp. 2750-2758 ◽  
Author(s):  
Yi-Ru Liu ◽  
Sheng-Yen Huang ◽  
Jen-Yang Chen ◽  
Lily Hui-Ching Wang
Keyword(s):  
Protein Kinase C ◽  
Life Cycle ◽  
Protein Kinase ◽  
Nasopharyngeal Carcinoma ◽  
Epstein Barr Virus ◽  
Lytic Cycle ◽  
Barr Virus ◽  
Kinase C ◽  
Epstein Barr ◽  
In Cells

Elevated levels of antibodies against Epstein–Barr virus (EBV) and the presence of viral DNA in plasma are reliable biomarkers for the diagnosis of nasopharyngeal carcinoma (NPC) in high-prevalence areas, such as South-East Asia. The presence of these viral markers in the circulation suggests that a minimal level of virus reactivation may have occurred in an infected individual, although the underlying mechanism of reactivation remains to be elucidated. Here, we showed that treatment with nocodazole, which provokes the depolymerization of microtubules, induces the expression of two EBV lytic cycle proteins, Zta and EA-D, in EBV-positive NPC cells. This effect was independent of mitotic arrest, as viral reactivation was not abolished in cells synchronized at interphase. Notably, the induction of Zta by nocodazole was mediated by transcriptional upregulation via protein kinase C (PKC). Pre-treatment with inhibitors for PKC or its downstream signalling partners p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK) abolished the nocodazole-mediated induction of Zta and EA-D. Interestingly, the effect of nocodazole, as well as colchicine and vinblastine, on lytic gene expression occurred only in NPC epithelial cells but not in cells derived from lymphocytes. These results establish a novel role of microtubule integrity in controlling the EBV life cycle through PKC and its downstream pathways, which represents a tissue-specific mechanism for controlling the life-cycle switch of EBV.

scholarly journals Coordinate changes in gene expression which mark the spinous to granular cell transition in epidermis are regulated by protein kinase C.

1993 ◽  
Vol 120 (1) ◽  
pp. 217-225 ◽  
Author(s):  
A A Dlugosz ◽  
S H Yuspa
Keyword(s):  
Gene Expression ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Mrna Expression ◽  
Granular Cell ◽  
Cell Markers ◽  
Kinase C ◽  
Coordinate Changes ◽  
Cell Transition ◽  
In Cells

The protective function of skin depends on successful completion of a tightly regulated multi-step differentiation program, during which the induction of markers for a specific stage in epidermal differentiation is coupled to repression of markers expressed at the preceding stage. We have explored the role of protein kinase C (PKC) in this process using an in vitro model system, in which cultures of primary mouse epidermal keratinocytes are induced to terminally differentiate by raising the Ca2+ concentration in the medium from 0.05 to 0.12 mM. At doses which activate PKC, 12-O-tetradecanoylphorbol-13-acetate (TPA) and 1-oleoyl-2-acetylglycerol block Ca(2+)-mediated induction of the spinous cell markers keratins K1 and K10 at both the protein and mRNA level. TPA and 1-oleoyl-2-acetylglycerol also rapidly repress K1 and K10 mRNA expression when added to differentiating keratinocyte cultures already expressing these markers. The inhibition of K1 mRNA expression by TPA is blocked in cells where PKC has been inactivated with bryostatin. TPA-mediated loss of K1 mRNA is also blocked in cells exposed to cycloheximide or actinomycin D implicating a PKC-induced protein factor in this process. The loss of K1 mRNA in TPA-treated cultures is the result of both a selective destabilization of K1 transcripts and a rapid inhibition of K1 gene transcription. In contrast to the dramatic repression of mRNAs typical for spinous cell differentiation, activation of PKC concurrently enhances expression of mRNAs and proteins for the granular cell markers loricrin and filaggrin. This response does not occur in cells pre-treated with bryostatin to inactivate PKC. Our results suggest that PKC is a fundamental regulator of the coordinate changes in keratinocyte gene expression that occur during the spinous to granular cell transition in epidermis.

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