1
|
Li G, Dang J, Pan J, Liu J, Peng T, Chen G, Wang R, Hu S, Li X, Hu X. Genome-Wide Analysis of the DC1 Domain Protein Gene Family in Tomatoes under Abiotic Stress. Int J Mol Sci 2023; 24:16994. [PMID: 38069320 PMCID: PMC10707348 DOI: 10.3390/ijms242316994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 11/27/2023] [Accepted: 11/28/2023] [Indexed: 12/18/2023] Open
Abstract
DC1 (Divergent C1) domain proteins are a new class of proteins that have been discovered in recent years, which play an important role in plant growth, development, and stress response. In order to better study the distribution and function of DC1 domain proteins in tomatoes, a genome-wide identification was conducted. It was found that there are twenty-one DC1 domain protein genes distributed on nine chromosomes of tomatoes, named SlCHP1-21. Phylogenetic analysis shows that twenty-one SlCHP genes are divided into six subfamilies. Most of the SlCHP genes in tomatoes have no or very short introns. All SlCHP proteins, with the exception of SlCHP8 and SlCHP17, contain variable amounts of C1 domain. Analysis of the SlCHP gene promoter sequence revealed multiple cis-elements responsive to plant stress. qRT-CR analysis showed that most members of SlCHP gene expressed in the roots. The SlCHP11, 13, 16, 17, and SlCHP20 genes showed specific responses to high temperature, low temperature, salt, and drought stress. In addition, the subcellular localization and interaction proteins of SlCHP were analyzed and predicted. Together, these results provides a theoretical basis for further exploration of the function and mechanism of the SlCHP gene in tomatoes.
Collapse
Affiliation(s)
- Guobin Li
- College of Horticulture, Northwest A&F University, Yangling 712100, China; (G.L.); (J.D.); (J.P.); (J.L.); (T.P.); (G.C.); (R.W.); (S.H.); (X.L.)
- Key Laboratory of Protected Horticultural Engineering in Northwest, Ministry of Agriculture, Yangling 712100, China
- Shaanxi Protected Agriculture Research Centre, Yangling 712100, China
| | - Jiao Dang
- College of Horticulture, Northwest A&F University, Yangling 712100, China; (G.L.); (J.D.); (J.P.); (J.L.); (T.P.); (G.C.); (R.W.); (S.H.); (X.L.)
- Key Laboratory of Protected Horticultural Engineering in Northwest, Ministry of Agriculture, Yangling 712100, China
- Shaanxi Protected Agriculture Research Centre, Yangling 712100, China
| | - Jiaqi Pan
- College of Horticulture, Northwest A&F University, Yangling 712100, China; (G.L.); (J.D.); (J.P.); (J.L.); (T.P.); (G.C.); (R.W.); (S.H.); (X.L.)
- Key Laboratory of Protected Horticultural Engineering in Northwest, Ministry of Agriculture, Yangling 712100, China
- Shaanxi Protected Agriculture Research Centre, Yangling 712100, China
| | - Jingyi Liu
- College of Horticulture, Northwest A&F University, Yangling 712100, China; (G.L.); (J.D.); (J.P.); (J.L.); (T.P.); (G.C.); (R.W.); (S.H.); (X.L.)
| | - Tieli Peng
- College of Horticulture, Northwest A&F University, Yangling 712100, China; (G.L.); (J.D.); (J.P.); (J.L.); (T.P.); (G.C.); (R.W.); (S.H.); (X.L.)
- Key Laboratory of Protected Horticultural Engineering in Northwest, Ministry of Agriculture, Yangling 712100, China
- Shaanxi Protected Agriculture Research Centre, Yangling 712100, China
| | - Guo Chen
- College of Horticulture, Northwest A&F University, Yangling 712100, China; (G.L.); (J.D.); (J.P.); (J.L.); (T.P.); (G.C.); (R.W.); (S.H.); (X.L.)
| | - Rongqun Wang
- College of Horticulture, Northwest A&F University, Yangling 712100, China; (G.L.); (J.D.); (J.P.); (J.L.); (T.P.); (G.C.); (R.W.); (S.H.); (X.L.)
| | - Songshen Hu
- College of Horticulture, Northwest A&F University, Yangling 712100, China; (G.L.); (J.D.); (J.P.); (J.L.); (T.P.); (G.C.); (R.W.); (S.H.); (X.L.)
- Key Laboratory of Protected Horticultural Engineering in Northwest, Ministry of Agriculture, Yangling 712100, China
- Shaanxi Protected Agriculture Research Centre, Yangling 712100, China
| | - Xiaojing Li
- College of Horticulture, Northwest A&F University, Yangling 712100, China; (G.L.); (J.D.); (J.P.); (J.L.); (T.P.); (G.C.); (R.W.); (S.H.); (X.L.)
- Key Laboratory of Protected Horticultural Engineering in Northwest, Ministry of Agriculture, Yangling 712100, China
- Shaanxi Protected Agriculture Research Centre, Yangling 712100, China
| | - Xiaohui Hu
- College of Horticulture, Northwest A&F University, Yangling 712100, China; (G.L.); (J.D.); (J.P.); (J.L.); (T.P.); (G.C.); (R.W.); (S.H.); (X.L.)
- Key Laboratory of Protected Horticultural Engineering in Northwest, Ministry of Agriculture, Yangling 712100, China
- Shaanxi Protected Agriculture Research Centre, Yangling 712100, China
| |
Collapse
|
2
|
Siao AC, Lin YY, Shih LJ, Tsuei YW, Chuu CP, Kuo YC, Kao YH. Endothelin-1 stimulates preadipocyte growth via the PKC, STAT3, AMPK, c-JUN, ERK, sphingosine kinase, and sphingomyelinase pathways. Am J Physiol Cell Physiol 2020; 319:C839-C857. [PMID: 32755450 DOI: 10.1152/ajpcell.00491.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Endothelin (ET)-1 regulates adipogenesis and the endocrine activity of fat cells. However, relatively little is known about the ET-1 signaling pathway in preadipocyte growth. We used 3T3-L1 preadipocytes to investigate the signaling pathways involved in ET-1 modulation of preadipocyte proliferation. As indicated by an increased number of cells and greater incorporation of bromodeoxyuridine (BrdU), the stimulation of preadipocyte growth by ET-1 depends on concentration and timing. The concentration of ET-1 that increased preadipocyte number by 51-67% was ~100 nM for ~24-48 h of treatment. ET-1 signaling time dependently stimulated phosphorylation of ERK, c-JUN, STAT3, AMPK, and PKCα/βII proteins but not AKT, JNK, or p38 MAPK. Treatment with an ETAR antagonist, such as BQ610, but not ETBR antagonist BQ788, blocked the ET-1-induced increase in cell proliferation and phosphorylated levels of ERK, c-JUN, STAT3, AMPK, and PKCα/βII proteins. In addition, pretreatment with specific inhibitors of ERK1/2 (U0126), JNK (SP600125), JAK2/STAT3 (AG490), AMPK (compound C), or PKC (Ro318220) prevented the ET-1-induced increase in cell proliferation and reduced the ET-1-stimulated phosphorylation of ERK1/2, c-JUN, STAT3, AMPK, and PKCα/β. Moreover, the SphK antagonist suppressed ET-1-induced cell proliferation and ERK, c-JUN, STAT3, AMPK, and PKC phosphorylation, and the SMase2 antagonist suppressed ET-1-induced cell proliferation. However, neither the p38 MAPK antagonist nor the CerS inhibitor altered the effect of ET-1. The results indicate that ETAR, JAK2/STAT3, ERK1/2, JNK/c-JUN, AMPK, PKC, SphK, and SMase2, but not ETBR, p38 MAPK, or CerS, are necessary for the ET-1 stimulation of preadipocyte proliferation.
Collapse
Affiliation(s)
- An-Ci Siao
- Department of Life Sciences, National Central University, Taoyuan, Taiwan
| | - Yen-Yue Lin
- Department of Life Sciences, National Central University, Taoyuan, Taiwan.,Department of Emergency, Taoyuan Armed Forces General Hospital, Taoyuan, Taiwan.,National Defense Medical Center, Taipei, Taiwan
| | - Li-Jane Shih
- National Defense Medical Center, Taipei, Taiwan.,Medical Laboratory, Taoyuan Armed Forces General Hospital, Taoyuan, Taiwan
| | - Yi-Wei Tsuei
- Department of Emergency, Taoyuan Armed Forces General Hospital, Taoyuan, Taiwan
| | - Chih-Pin Chuu
- Institute of Cellular and System Medicine, National Health Research Institutes, Zhunan, Miaoli County, Taiwan
| | - Yow-Chii Kuo
- Division of Gastroenterology, Landseed Hospital, Taoyuan, Taiwan
| | - Yung-Hsi Kao
- Department of Life Sciences, National Central University, Taoyuan, Taiwan
| |
Collapse
|
3
|
Al-Bayati A, Lukka D, Brown AE, Walker M. Effects of thrombin on insulin signalling and glucose uptake in cultured human myotubes. J Diabetes Complications 2016; 30:1209-16. [PMID: 27396242 DOI: 10.1016/j.jdiacomp.2016.06.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 05/19/2016] [Accepted: 06/14/2016] [Indexed: 01/22/2023]
Abstract
BACKGROUND Hyper-coagulability (elevated thrombin) is a feature of type 2 diabetes and contributes to an increased risk of thrombotic and vascular events. Skeletal muscle is the key peripheral tissue site of insulin resistance in type 2 diabetes. Cultured human skeletal muscle cells were used to explore the effects of thrombin on insulin signalling and glucose uptake. We hypothesized that thrombin affects insulin activity in human skeletal muscle cells which could link the hypercoagulability and insulin resistance in type 2 diabetes. METHODS Human skeletal muscle cell cultures (myotubes) were treated with +/-5 units/ml thrombin for 6h. Insulin signalling pathway components and AMPK were examined by Western blotting. Real time PCR and glucose uptake assays were performed. RESULTS There was a significant decrease (p<0.01) in insulin mediated IRS-1 and Akt phosphorylation in response to thrombin in cultured myotubes. Diminished Akt phosphorylation was alleviated by treatment with a PKC inhibitor. Thrombin directly increased basal glucose uptake (p<0.05) that involved AMPK phosphorylation (p<0.01) and this was partly repressed by compound C (AMPK inhibitor). Thrombin also significantly increased the gene expression level of both GLUT1 and GLUT4 in cultured human skeletal muscle cells. CONCLUSION Thrombin decreased insulin signalling in skeletal muscle cells through a PKC mediated mechanism, but did not affect the net action of insulin on glucose uptake. The direct stimulatory effect of thrombin on glucose uptake was mediated, at least in part, via an AMPK dependent mechanism. We conclude that thrombin activation results in multiple metabolic effects beyond increased thrombogenicity but does not include a decrease in insulin sensitivity (glucose uptake) in cultured human skeletal muscle cells.
Collapse
Affiliation(s)
- Ali Al-Bayati
- Diabetes Research Group, Institute of Cellular Medicine, Medical School, Newcastle University, Newcastle upon Tyne, United Kingdom.
| | - Dhanisha Lukka
- Diabetes Research Group, Institute of Cellular Medicine, Medical School, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Audrey E Brown
- Diabetes Research Group, Institute of Cellular Medicine, Medical School, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Mark Walker
- Diabetes Research Group, Institute of Cellular Medicine, Medical School, Newcastle University, Newcastle upon Tyne, United Kingdom
| |
Collapse
|
4
|
Lee YY, Ryu MS, Kim HS, Suganuma M, Song KY, Lim IK. Regulations of Reversal of Senescence by PKC Isozymes in Response to 12-O-Tetradecanoylphorbol-13-Acetate via Nuclear Translocation of pErk1/2. Mol Cells 2016; 39:266-79. [PMID: 26912086 PMCID: PMC4794609 DOI: 10.14348/molcells.2016.2362] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Accepted: 12/31/2015] [Indexed: 11/27/2022] Open
Abstract
The mechanism by which 12-O-tetradecanoylphorbol-13-acetate (TPA) bypasses cellular senescence was investigated using human diploid fibroblast (HDF) cell replicative senescence as a model. Upon TPA treatment, protein kinase C (PKC) α and PKCβ1 exerted differential effects on the nuclear translocation of cytoplasmic pErk1/2, a protein which maintains senescence. PKCα accompanied pErk1/2 to the nucleus after freeing it from PEA-15pS(104) via PKCβ1 and then was rapidly ubiquitinated and degraded within the nucleus. Mitogen-activated protein kinase docking motif and kinase activity of PKCα were both required for pErk1/2 transport to the nucleus. Repetitive exposure of mouse skin to TPA downregulated PKCα expression and increased epidermal and hair follicle cell proliferation. Thus, PKCα downregulation is accompanied by in vivo cell proliferation, as evidenced in 7, 12-dimethylbenz(a)anthracene (DMBA)-TPA-mediated carcinogenesis. The ability of TPA to reverse senescence was further demonstrated in old HDF cells using RNA-sequencing analyses in which TPA-induced nuclear PKCα degradation freed nuclear pErk1/2 to induce cell proliferation and facilitated the recovery of mitochondrial energy metabolism. Our data indicate that TPA-induced senescence reversal and carcinogenesis promotion share the same molecular pathway. Loss of PKCα expression following TPA treatment reduces pErk1/2-activated SP1 biding to the p21(WAF1) gene promoter, thus preventing senescence onset and overcoming G1/S cell cycle arrest in senescent cells.
Collapse
Affiliation(s)
- Yun Yeong Lee
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon 443-380,
Korea
| | - Min Sook Ryu
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon 443-380,
Korea
| | | | - Masami Suganuma
- Research Institute for Clinical Oncology, Saitama Cancer Center, Saitama,
Japan
| | - Kye Yong Song
- Department of Pathology, Chung-Ang University College of Medicine, Seoul 156-756,
Korea
| | - In Kyoung Lim
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon 443-380,
Korea
| |
Collapse
|
5
|
Lim PS, Sutton CR, Rao S. Protein kinase C in the immune system: from signalling to chromatin regulation. Immunology 2015; 146:508-22. [PMID: 26194700 DOI: 10.1111/imm.12510] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 06/29/2015] [Accepted: 07/15/2015] [Indexed: 12/12/2022] Open
Abstract
Protein kinase C (PKC) form a key family of enzymes involved in signalling pathways that specifically phosphorylates substrates at serine/threonine residues. Phosphorylation by PKC is important in regulating a variety of cellular events such as cell proliferation and the regulation of gene expression. In the immune system, PKCs are involved in regulating signal transduction pathways important for both innate and adaptive immunity, ultimately resulting in the expression of key immune genes. PKCs act as mediators during immune cell signalling through the immunological synapse. PKCs are traditionally known to be cytoplasmic signal transducers and are well embedded in the signalling pathways of cells to mediate the cells' response to a stimulus from the plasma membrane to the nucleus. PKCs are also found to transduce signals within the nucleus, a process that is distinct from the cytoplasmic signalling pathway. There is now growing evidence suggesting that PKC can directly regulate gene expression programmes through a non-traditional role as nuclear kinases. In this review, we will focus on the role of PKCs as key cytoplasmic signal transducers in immune cell signalling, as well as its role in nuclear signal transduction. We will also highlight recent evidence for its newly discovered regulatory role in the nucleus as a chromatin-associated kinase.
Collapse
Affiliation(s)
- Pek Siew Lim
- Discipline of Biomedical Sciences, Faculty of Applied Science, University of Canberra, Canberra, ACT, Australia
| | - Christopher Ray Sutton
- Discipline of Biomedical Sciences, Faculty of Applied Science, University of Canberra, Canberra, ACT, Australia
| | - Sudha Rao
- Discipline of Biomedical Sciences, Faculty of Applied Science, University of Canberra, Canberra, ACT, Australia
| |
Collapse
|
6
|
Expression and proliferation profiles of PKC, JNK and p38MAPK in physiologically stretched human bladder smooth muscle cells. Biochem Biophys Res Commun 2013; 438:479-82. [PMID: 23916702 DOI: 10.1016/j.bbrc.2013.07.115] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 07/29/2013] [Indexed: 02/05/2023]
Abstract
OBJECTIVE To determine protein kinase C (PKC), c-Jun NH2-Terminal Kinase (JNK) and P38 mitogen-activated protein kinases (p38MAPK) expression levels and effects of their respective inhibitors on proliferation of human bladder smooth muscle cells (HBSMCs) when physiologically stretched in vitro. MATERIALS AND METHODS HBSMCs were grown on silicone membrane and stretch was applied under varying conditions; (equibiaxial elongation: 2.5%, 5%, 10%, 15%, 20%, 25%), (frequency: 0.05, 0.1, 0.2, 0.5, 1Hz). Optimal physiological stretch was established by assessing proliferation with 5-Bromo-2-deoxyuridine (BrdU) assay and flow cytometry. PKC, JNK and p38 expression levels were analyzed by Western blot. Specificity was maintained by employing specific inhibitors; (GF109203X for PKC, SP600125 for JNK and SB203580 for p38MAPK), in some experiments. RESULTS Optimum proliferation was observed at 5% equibiaxial stretch (BrdU: 0.837±0.026 (control) to 1.462±0.023)%, (P<0.05) and apoptotic cell death rate decreased from 16.4±0.21% (control) to 4.5±0.13% (P<0.05) applied at 0.1Hz. Expression of PKC was upregulated with slight increase in JNK and no change in p38MAPK after application of stretch. Inhibition had effects on proliferation (1.075±0.024, P<0.05 GF109203X); (1.418±0.021, P>0.05 SP600125) and (1.461±0.01, P>0.05 SB203580). These findings show that mechanical stretch can promote magnitude-dependent proliferative modulation through PKC and possibly JNK but not via p38MAPK in hBSMCs.
Collapse
|
7
|
A role for protein kinase C in the regulation of membrane fluidity and Ca²(+) flux at the endoplasmic reticulum and plasma membranes of HEK293 and Jurkat cells. Cell Signal 2010; 23:497-505. [PMID: 21062642 DOI: 10.1016/j.cellsig.2010.11.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Revised: 10/19/2010] [Accepted: 11/02/2010] [Indexed: 10/18/2022]
Abstract
Protein kinase C (PKC) plays a prominent role in the regulation of a variety of cellular functions, including Ca²(+) signalling. In HEK293 and Jurkat cells, the Ca²(+) release and Ca²(+) uptake stimulated by several different activators were attenuated by activation of PKC with phorbol myristate acetate (PMA) or 1-oleoyl-2-acetyl-sn-glycerol (OAG) and potentiated by PKC inhibition with Gö6983 or knockdown of PKCα or PKCβ using shRNA. Immunostaining and Western blotting analyses revealed that PKCα and PKCβII accumulated at the plasma membrane (PM) and that these isoforms, along with PKCβI, also translocated to the endoplasmic reticulum (ER) upon activation with PMA. Measurements of membrane fluidity showed that, like the cell membrane stabilizers bovine serum albumin (BSA) and ursodeoxycholate (UDCA), PMA and OAG significantly reduced the fluidity of both the PM and ER membranes; these effects were blocked in PKC-knockdown cells. Interestingly, both BSA and UDCA inhibited the Ca²(+) responses to agonists to the same extent as PMA, whereas Tween 20, which increases membrane fluidity, raised the internal Ca²(+) concentration. Thus, activation of PKC induces both translocation of PKC to the PM and ER membranes and downregulation of membrane fluidity, thereby negatively modulating Ca²(+) flux.
Collapse
|
8
|
Valdehita A, Bajo AM, Fernández-Martínez AB, Arenas MI, Vacas E, Valenzuela P, Ruíz-Villaespesa A, Prieto JC, Carmena MJ. Nuclear localization of vasoactive intestinal peptide (VIP) receptors in human breast cancer. Peptides 2010; 31:2035-45. [PMID: 20691743 DOI: 10.1016/j.peptides.2010.07.024] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Revised: 07/28/2010] [Accepted: 07/28/2010] [Indexed: 12/12/2022]
Abstract
Vasoactive intestinal peptide (VIP) and its receptors (VPACs) are involved in proliferation, survival, and differentiation in human breast cancer cells. Its mechanism of action is traditionally thought to be through specific plasma membrane receptors. There is compelling evidence for a novel intracrine mode of genomic regulation by G-protein-coupled receptors (GPCRs) that implies both endocytosis and nuclear translocation of peripheral GPCR and/or the activation of nuclear-located GPCRs by endogenously-produced, non-secreted ligands. Regarding to VPAC receptors, which are GPCRs, there is only a report suggesting them as a dynamic system for signaling from plasma membrane and nuclear membrane complex. In this study, we show that VPAC(1) receptor is localized in cell nuclear fraction whereas VPAC(2) receptor presents an extranuclear localization and its protein expression is lower than that of VPAC(1) receptor in human breast tissue samples. Both receptors as well as VIP are overexpressed in breast cancer as compared to non-tumor tissue. Moreover, we report the markedly nuclear localization of VPAC(1) receptors in estrogen-dependent (T47D) and independent (MDA-MB-468) human breast cancer cell lines. VPAC(1) receptors are functional in plasma membrane and nucleus as shown by VIP stimulation of cAMP production in both cell lines. In addition, VIP increases its own intracellular and extracellular levels, and could be involved in the regulation of VPAC(1)-receptor traffic from the plasma membrane to the nucleus. These results support new concepts on function and regulation of nuclear GPCRs which could have an impact on development of new therapeutic drugs.
Collapse
Affiliation(s)
- Ana Valdehita
- Molecular Neuroendocrinology Unit, Department of Biochemistry and Molecular Biology, Alcalá University, 28871 Alcalá de Henares, Spain
| | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Horovitz-Fried M, Brutman-Barazani T, Kesten D, Sampson SR. Insulin increases nuclear protein kinase Cdelta in L6 skeletal muscle cells. Endocrinology 2008; 149:1718-27. [PMID: 18162512 DOI: 10.1210/en.2007-1572] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Protein kinase C (PKC) isoforms are involved in the transduction of a number of signals important for the regulation of cell growth, differentiation, apoptosis, and other cellular functions. PKC proteins reside in the cytoplasm in an inactive state translocate to various membranes to become fully activated in the presence of specific cofactors. Recent evidence indicates that PKC isoforms have an important role in the nucleus. We recently showed that insulin rapidly increases PKCdelta RNA and protein. In this study we initially found that insulin induces an increase in PKCdelta protein in the nuclear fraction. We therefore attempted to elucidate the mechanism of the insulin-induced increase in nuclear PKCdelta. Studies were performed on L6 skeletal myoblasts and myotubes. The increase in nuclear PKCdelta appeared to be unique to insulin because it was not induced by other growth factors or rosiglitazone. Inhibition of transcription or translation blocked the insulin-induced increase in nuclear PKCdelta, whereas inhibition of protein import did not. Inhibition of protein export from the nucleus reduced the insulin-induced increase in PKCdelta in the cytoplasm and increased it in the nucleus. The increase in nuclear PKCdelta induced by insulin was reduced but not abrogated by treatment of isolated nuclei by trypsin digestion. Finally, we showed that insulin induced incorporation of (35)S-methionine into nuclear PKCdelta protein; this effect was not blocked by inhibition of nuclear import. Thus, these results suggest that insulin may induce nuclear-associated, or possibly nuclear, translation of PKCdelta protein.
Collapse
|
10
|
Zini N, Bavelloni A, Lisignoli G, Ghisu S, Valmori A, Martelli AM, Facchini A, Maraldi NM. PKC-ζ expression is lower in osteoblasts from arthritic patients: IL1-β and TNF-α induce a similar decrease in non-arthritic human osteoblasts. J Cell Biochem 2008; 103:547-55. [PMID: 17541951 DOI: 10.1002/jcb.21424] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Protein kinase C (PKC) is a family of enzymes detected in a diverse range of cell types where they regulate various cellular functions such as proliferation, differentiation, cytoskeletal remodelling, cytokine production, and receptor-mediated signal transduction. In this study we have analyzed the expression of 11 PKC isoforms (-alpha, -beta(I), -beta(II), -gamma, -delta, -eta, -theta, -epsilon, -zeta, -iota/lambda, and -micro) in osteoblasts from patients with osteoarthritis (OA) and rheumatoid arthritis (RA) in comparison with osteoblasts from post-traumatic (PT) patients. By Western blotting analysis, nine isoforms, -alpha, -beta(I), -beta(II), -delta, -theta, - epsilon, -zeta, - iota/lambda, and -micro, were detected in osteoblasts. In RA and OA patients, PKC -theta and -micro were greater expressed whereas PKC-epsilon and -zeta decreased when compared with normal cells. The subcellular distribution and quantitative differences were confirmed by immuno-electron microscopy. Furthermore, we demonstrated that treatment with the proinflammatory cytokines, IL-1beta and TNF-alpha, significantly decreased PKC-zeta expression in PT osteoblasts. This suggests that proinflammatory cytokines can modulate the expression of this PKC isoform in osteoblasts in a way which is similar to changes detected in arthritic patients.
Collapse
Affiliation(s)
- Nicoletta Zini
- IGM-CNR, Sezione di Bologna c/o IOR, via di Barbiano 1/10, 40136 Bologna, Italy
| | | | | | | | | | | | | | | |
Collapse
|
11
|
Design and physicochemical properties of new fluorescent ligands of protein kinase C isozymes focused on CH/pi interaction. Bioorg Med Chem 2007; 16:650-7. [PMID: 17977729 DOI: 10.1016/j.bmc.2007.10.045] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2007] [Revised: 10/13/2007] [Accepted: 10/16/2007] [Indexed: 11/22/2022]
Abstract
Phorbol ester-type tumor promoters such as indolactam-V (IL-V, 1) bind to the C1 domains of protein kinase C (PKC) isozymes. A more convenient method to investigate the interaction between each tumor promoter and PKC C1 domain is needed. Focusing on our recent finding that the indole ring of IL-V is involved in the CH/pi interaction with Pro-11 of the PKCdelta-C1B domain, we developed new fluorescent probes (2-4) from IL-V by forming a pyrroloindazole ring. Compound 2 without a substituent at the pyrroloindazole ring bound most strongly to PKC C1 domains with a potency similar to IL-V, but its fluorescent intensity was the weakest of any of the probes. Although the binding affinity of 3 with a methyl group was significantly weaker than that of IL-V, 4 with a trifluoromethyl group showed moderate affinity and the most potent fluorescence intensity. The fluorescence intensity and emission maxima of 4 changed significantly when bound to the PKCdelta-C1B peptide in both the presence and absence of phosphatidylserine. These results suggest that 4 could be a useful probe for analyzing the interaction of tumor promoters with PKC C1 domains.
Collapse
|
12
|
Xu W, Zha RP, Wang WY, Wang YP. Effects of scutellarin on PKCgamma in PC12 cell injury induced by oxygen and glucose deprivation. Acta Pharmacol Sin 2007; 28:1573-9. [PMID: 17883942 DOI: 10.1111/j.1745-7254.2007.00502.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
AIM To evaluate the neuroprotective effect and mechanisms of scutellarin (Scu) against PC12 cell injury after oxygen and glucose deprivation followed by reperfusion (OGD-Rep). METHODS Undifferentiated rat pheochromocytoma PC12 cells, exposed to oxygen and glucose deprivation followed by reperfusion (OGD-Rep), used as an in vitro model of ischemia/reperfusion. Cell survival was evaluated by diphenyltetrazolium bromide (MTT) assay and the amount of LDH release was determined using assay kits. [Ca2+](i) was monitored using a fluorescent Ca2+-sensitive dye Fura-2 acetoxymethyl ester. Cell apoptosis was detected by a DNA ladder and by flow cytometric detection. The expression of protein kinase C (PKC)gamma was determined using both RT-PCR and Western blotting. The translocation of PKCgamma was assayed by subcellular fractionation and Western blotting. RESULTS OGD-Rep injury significantly elevated the level of LDH release, [Ca2+](i), mRNA expression and the translocation of PKCgamma compared in the PC12 cells with those of the normal group. Scu (10-100 micromol/L) exerted a protective effect against OGD-Rep injury by reducing LDH release, [Ca2+](i), the percent of apoptosis, and the translocation of PKCgamma. CONCLUSION Scu inhibits the increase of [Ca2+](i) and the activation of PKCgamma, exerting protective effects against PC12 cell injury induced by OGD-Rep.
Collapse
Affiliation(s)
- Wei Xu
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 201203, China
| | | | | | | |
Collapse
|
13
|
Washington B, Williams S, Armstrong P, Mtshali C, Robinson JT, Myles EL. Cadmium Toxicity on Arterioles Vascular Smooth Muscle Cells of Spontaneously Hypertensive Rats. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2006; 3:323-8. [PMID: 17159273 DOI: 10.3390/ijerph2006030040] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cadmium (Cd) is frequently used in various industrial applications and is a ubiquitous environmental toxicant, also present in tobacco smoke. An important route of exposure is the circulatory system whereas blood vessels are considered to be main stream organs of Cd toxicity. Our previous results indicate that cadmium chloride (CdCl2) affects mean arterial blood pressure in hypertensive rats. We hypothesized that Cd alters the intracellular calcium transient mechanism, by cadmium-induced stimulation of MAPKs (ERK 1 & 2) which is mediated partially through calcium-dependent PKC mechanism. To investigate this hypothesis, we exposed primary cultures of vascular smooth muscle cells (VSMCs) from wistar kyoto (WKY) and spontaneously hypertensive rats (SHR) to increased concentrations of CdCl2 on cell viability, expression of mitogen-activated protein kinases (MAPKs/ERK 1 & 2), and protein kinase C (PKC) which are activated by Cd in several cell types. The results from these studies indicate that CdCl2 decreased cell viability of both SHR and WKY VSMCs in a concentration dependent-manner. Viability of both cell types decreased 33+/-5.3 (SHR) and 39+/-2.3% (WKY) when exposed to 1 microM CdCl2, whereas, 8 and 16 microM reduced viability by 66+/-3.1 and 62+/-4.5% in SHR cells. CdCl2 increased ERK 1 & 2 in a biphasic manner with maximum increase occurring when cells are exposed to 1 and 4 muM in SHR VSMCs, whereas, a reduction in ERK 1 and 2 is observed when WKY cells are treated with 2 microM. The results also indicate that CdCl2 increased PKC a/Beta in both SHR and WKY VSMCs with a greater increase in expression in SHR VSMCs. In addition, the [Ca2+]i chelator, BAPTA, suppressed the CdCl2 effect, whereas, the PKC inhibitor, GF109203X, reduced the CdCl2 induced-effect on PKC expression. The present studies support the hypothesis that Cd can be a risk factor of hypertension through dysfunction of vascular smooth muscle cells under certain conditions.
Collapse
MESH Headings
- Animals
- Cadmium/toxicity
- Cadmium Poisoning/pathology
- Cell Survival/drug effects
- Cells, Cultured
- Dose-Response Relationship, Drug
- Mitogen-Activated Protein Kinase Kinases/metabolism
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/enzymology
- Muscle, Smooth, Vascular/metabolism
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/enzymology
- Myocytes, Smooth Muscle/metabolism
- Protein Kinase C/metabolism
- Rats
- Rats, Inbred SHR
Collapse
Affiliation(s)
- Benny Washington
- Department of Biological Sciences, Tennessee State University, Nashville, TN 37209, USA.
| | | | | | | | | | | |
Collapse
|
14
|
Iaccio A, Collinet C, Gesualdi NM, Ammendola R. Protein kinase C-alpha and -delta are required for NADPH oxidase activation in WKYMVm-stimulated IMR90 human fibroblasts. Arch Biochem Biophys 2006; 459:288-94. [PMID: 17166481 DOI: 10.1016/j.abb.2006.11.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2006] [Accepted: 11/08/2006] [Indexed: 11/22/2022]
Abstract
The regulation of the activation of non phagocytic NADPH oxidase is poorly understood. Previously we demonstrated that in fibroblasts the exposure to WKYMVm induced p47(phox) phosphorylation and translocation and that these effects were mediated by ERKs activation. Protein kinase C (PKC) is reported to be involved in regulating the phosphorylation of NADPH oxidase components in polymorphonucleate cells stimulated via FPRL1 receptor, but its involvement in fibroblasts was not demonstrated. Therefore, we investigated in IMR90 cells exposed to WKYMVm the role of PKC isoenzymes in the activation of NADPH oxidase-like enzyme. Preincubation with general pharmacological inhibitors of PKC, before stimulation with WKYMVm, prevented the ERKs activation, p47(phox) phosphorylation and translocation. The analysis of cellular partitioning of PKC isoenzymes demonstrated that PKCalpha and PKCdelta translocated from the cytosolic to the membrane fraction upon stimulation with WKYMVm. Preincubation with Gö6976 or with rottlerin prevented the phosphorylation and translocation of NADPH oxidase regulatory subunit.
Collapse
|
15
|
Zhu T, Gobeil F, Vazquez-Tello A, Leduc M, Rihakova L, Bossolasco M, Bkaily G, Peri K, Varma DR, Orvoine R, Chemtob S. Intracrine signaling through lipid mediators and their cognate nuclear G-protein-coupled receptors: a paradigm based on PGE2, PAF, and LPA1 receptors. Can J Physiol Pharmacol 2006; 84:377-91. [PMID: 16902584 DOI: 10.1139/y05-147] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Prostaglandins (PGs), platelet-activating factor (PAF), and lysophosphatidic acid (LPA) are ubiquitous lipid mediators that play important roles in inflammation, cardiovascular homeostasis, and immunity and are also known to modulate gene expression of specific pro-inflammatory genes. The mechanism of action of these lipids is thought to be primarily dependent on their specific plasma membrane receptors belonging to the superfamily of G-protein-coupled receptors (GPCR). Increasing evidence suggests the existence of a functional intracellular GPCR population. It has been proposed that immediate effects are mediated via cell surface receptors whereas long-term responses are dependent upon intracellular receptor effects. Indeed, receptors for PAF, LPA, and PGE(2) (specifically EP(1), EP(3), and EP(4)) localize at the cell nucleus of cerebral microvascular endothelial cells of newborn pigs, rat hepatocytes, and cells overexpressing each receptor. Stimulation of isolated nuclei with these lipids reveals biological functions including transcriptional regulation of major genes, namely c-fos, cylooxygenase-2, and endothelial as well as inducible nitric oxide synthase. In the present review, we shall focus on the nuclear localization and signaling of GPCRs recognizing PGE(2), PAF, and LPA phospholipids as ligands. Mechanisms on how nuclear PGE2, PAF, and LPA receptors activate gene transcription and nuclear localization pathways are presented. Intracrine signaling for lipid mediators uncover novel pathways to elicit their effects; accordingly, intracellular GPCRs constitute a distinctive mode of action for gene regulation.
Collapse
Affiliation(s)
- Tang Zhu
- Department of Pediatrics, Research Center of Hôpital Sainte-Justine, Université de Montréal, QC, Canada
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Marchisio M, Bertagnolo V, Lanuti P, Gaspari AR, Paludi M, Ciccocioppo F, Ercolino E, Bascelli A, Cataldi A, Miscia S. Nuclear protein kinase C-delta: a possible check-point of cell cycle progression. Int J Immunopathol Pharmacol 2006; 19:287-91. [PMID: 16831296 DOI: 10.1177/039463200601900206] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Protein kinase Cs (PKCs) belong to a serine/threonine kinase family, ubiquitously expressed and claimed to be involved in physiological processes including apoptosis, cell growth and differentiation. The question of the subcellular localization and activity of PKCs remains to be clarified. Here we report that nuclear PKC-delta cooperates to regulate the S-G2/M phase transition of cell cycle, apparently being associated to chromosome condensation and alignment on the metaphase plate.
Collapse
Affiliation(s)
- M Marchisio
- Cell Signalling Unit at the Department of Biomorphology, University of Chieti-Pescara, Italy
| | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Li HB, Ge YK, Zhang L, Zheng XX. Astragaloside IV improved barrier dysfunction induced by acute high glucose in human umbilical vein endothelial cells. Life Sci 2006; 79:1186-93. [PMID: 16650877 DOI: 10.1016/j.lfs.2006.03.041] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2005] [Revised: 03/08/2006] [Accepted: 03/16/2006] [Indexed: 01/30/2023]
Abstract
The purpose of the present study was to examine the effects of astragaloside IV, a saponin isolated from Astragalus membranaceus (Fisch) Bge, on the impairment of barrier function induced by acute high glucose in cultured human vein endothelial cells. High glucose (27.8 mM) induced a decrease in transendothelial electrical impedance and an increase in cell monolayer permeability in human umbilical vein endothelial cells. Endothelial barrier dysfunction stimulated by high glucose was accompanied by translocation and activation of protein kinase C (PKC), the redistribution of F-actin and formation of intercellular gaps, suggesting that increases in PKC activity and rearrangement of F-actin could be associated with endothelial barrier dysfunction induced by acute high glucose. Application of astragaloside IV inhibited high glucose-induced endothelial barrier dysfunction in a dose-dependent manner, which is compatible with inhibition of PKC translocation and improvement of F-actin rearrangements. Western blot analysis revealed that high glucose-induced PKC alpha and beta2 overexpression in the membrane fraction were significantly reduced by astragaloside IV. These findings indicate that astragaloside IV protected endothelial cells from high glucose-induced barrier impairment by inhibiting PKC activation, as well as improving cytoskeleton remodeling.
Collapse
Affiliation(s)
- Han-Bing Li
- Department of Biomedical Engineering, Zhejiang University (Yuquan Campus), Hangzhou 310027, PR China
| | | | | | | |
Collapse
|
18
|
Bour G, Taneja R, Rochette‐Egly C. Mouse embryocarcinoma F9 cells and retinoic acid: A model to study the molecular mechanisms of endodermal differentiation. NUCLEAR RECEPTORS IN DEVELOPMENT 2006. [DOI: 10.1016/s1574-3349(06)16007-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
|
19
|
Marrache AM, Gobeil F, Zhu T, Chemtob S. Intracellular signaling of lipid mediators via cognate nuclear G protein-coupled receptors. ACTA ACUST UNITED AC 2005; 12:63-72. [PMID: 16036317 DOI: 10.1080/10623320590933815] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Platelet-activating factor (PAF) and lysophosphatidic acid (LPA) are ubiquitous lipid mediators that play important roles in inflammation, cardiovascular homeostasis, and immunity and are also known to modulate gene expression of specific proinflammatory genes. The mechanism of action of these phospholipids is thought to be primarily dependent on their specific plasma membrane receptors belonging to the superfamily of G protein-coupled receptors (GPCRs). However, increasing evidence suggests the existence of a functional intracellular GPCR population. It has been suggested that immediate effects are mediated by cell surface receptors, whereas long-term responses are mediated by intracellular receptors. PAF and LPA(1) receptors localize at the cell nucleus of cerebral microvascular endothelial cells of newborn pig, rat hepatocytes, and cells overexpressing each receptor, and stimulation of isolated nuclei reveal biological functions, including transcriptional regulation of major genes, namely cylooxygenase-2 and inducible nitric oxide synthase. This mini review focuses on the nuclear localization and signaling of GPCRs, recognizing PAF and LPA phospholipids as ligands. Theories on how nuclear PAF and LPA1 receptors activate gene transcription and nuclear localization pathways are discussed. Intracrine signaling for lipid mediators uncover novel pathways to elicit their effects; moreover, intracellular GPCRs constitute a distinctive mode of action for gene regulation.
Collapse
|
20
|
Zhao M, Sutherland C, Wilson DP, Deng J, Macdonald JA, Walsh MP. Identification of the linker histone H1 as a protein kinase Cepsilon-binding protein in vascular smooth muscle. Biochem Cell Biol 2005; 82:538-46. [PMID: 15499382 DOI: 10.1139/o04-053] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
A variety of anchoring proteins target specific protein kinase C (PKC) isoenzymes to particular subcellular locations or multimeric signaling complexes, thereby achieving a high degree of substrate specificity by localizing the kinase in proximity to specific substrates. PKCepsilon is widely expressed in smooth muscle tissues, but little is known about its targeting and substrate specificity. We have used a Far-Western (overlay) approach to identify PKCepsilon-binding proteins in vascular smooth muscle of the rat aorta. Proteins of approximately 32 and 34 kDa in the Triton-insoluble fraction were found to bind PKCepsilon in a phospholipid/diacylglycerol-dependent manner. Although of similar molecular weight to RACK-1, a known PKCepsilon-binding protein, these proteins were separated from RACK-1 by SDS-PAGE and differential NaCl extraction and were not recognized by an antibody to RACK-1. The PKCepsilon-binding proteins were further purified from the Triton-insoluble fraction and identified by de novo sequencing of selected tryptic peptides by tandem mass spectrometry as variants of the linker histone H1. Their identity was confirmed by Western blotting with anti-histone H1 and the demonstration that purified histone H1 binds PKCepsilon in the presence of phospholipid and diacylglycerol but absence of Ca(2+). The interaction of PKCepsilon with histone H1 was specific since no interaction was observed with histones H2A, H2S or H3S. Bound PKCepsilon phosphorylated histone H1 in a phospholipid/diacylglycerol-dependent but Ca(2+)-independent manner. Ca(2+)-dependent PKC was also shown to interact with histone H1 but not other histones. These results suggest that histone H1 is both an anchoring protein and a substrate for activated PKCepsilon and other PKC isoenzymes and likely serves to localize activated PKCs that translocate to the nucleus in the vicinity of specific nuclear substrates including histone H1 itself. Since PKC isoenzymes have been implicated in regulation of gene expression, stable interaction with histone H1 may be an important step in this process.
Collapse
Affiliation(s)
- Mingcai Zhao
- Smooth Muscle Research Group and Department of Biochemistry and Molecular Biology, University of Calgary Faculty of Medicine, 330 Hospital Drive N.W., Calgary, AB T2N 4N1, Canada
| | | | | | | | | | | |
Collapse
|
21
|
Avazeri N, Courtot AM, Lefevre B. Regulation of spontaneous meiosis resumption in mouse oocytes by various conventional PKC isozymes depends on cellular compartmentalization. J Cell Sci 2004; 117:4969-78. [PMID: 15367584 DOI: 10.1242/jcs.01375] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this study, we investigated the spatio-temporal distribution of conventional protein kinases C (cPKC) isoforms PKC-alpha, PKC-betaI, PKC-betaII and PKC-gamma in mouse oocytes. The cPKCs were present in the cytoplasm at the start of the process and migrated to the nucleus (or germinal vesicle) before germinal vesicle breakdown, except for PKC-gamma which remained cytoplasmic. In both compartments, the fully phosphorylated form corresponding to the 'mature' enzyme was revealed for PKC-alpha, PKC-betaI and PKC-betaII. Microinjection of specific antibodies against each isozyme in one or the other cell compartment at different times of the meiotic process, permitted us to observe the following: (1) When located in the cytoplasm at the beginning of the process, PKC-alpha is not implicated in germinal vesicle breakdown, PKC-betaI and PKC-gamma are involved in maintaining the meiotic arrest, and PKC-betaII plays a role in meiosis reinitiation. Furthermore, just before germinal vesicle breakdown, these cytoplasmic cPKCs were no longer implicated. (2) When located in the germinal vesicle, PKC-alpha, PKC-betaI and PKC-betaII are involved in meiosis reinitiation. Our data highlight not only the importance of the nuclear pathways in the cell cycle progression, but also their independence of the cytoplasmic ones. Further investigations are however necessary to discover the molecular targets of these cPKCs to better understand the links with the cell cycle progression.
Collapse
Affiliation(s)
- Nathalie Avazeri
- Institut National de la Santé et de la Recherche Médicale Unité 566 Commissariat à l'Energie Atomique, 92260 Fontenay-aux-Roses CEDEX, France
| | | | | |
Collapse
|
22
|
Vijayan K, Szotek EL, Martin JL, Samarel AM. Protein kinase C-alpha-induced hypertrophy of neonatal rat ventricular myocytes. Am J Physiol Heart Circ Physiol 2004; 287:H2777-89. [PMID: 15271671 DOI: 10.1152/ajpheart.00171.2004] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Protein kinase C (PKC) isoenzymes play a critical role in cardiomyocyte hypertrophy. At least three different phorbol ester-sensitive PKC isoenzymes are expressed in neonatal rat ventricular myocytes (NRVMs): PKC-alpha, -delta, and -epsilon. Using replication-defective adenoviruses (AdVs) that express wild-type (WT) and dominant-negative (DN) PKC-alpha together with phorbol myristate acetate (PMA), which is a hypertrophic agonist and activator of all three PKC isoenzymes, we studied the role of PKC-alpha in signaling-specific aspects of the hypertrophic phenotype. PMA induced nuclear translocation of endogenous and AdV-WT PKC-alpha in NRVMs. WT PKC-alpha overexpression increased protein synthesis and the protein-to-DNA (P/D) ratio but did not affect cell surface area (CSA) or cell shape compared with uninfected or control AdV beta-galactosidase (AdV betagal)-infected cells. PMA-treated uninfected cells displayed increased protein synthesis, P/D ratio, and CSA and elongated morphology. PMA did not further enhance protein synthesis or P/D ratio in AdV-WT PKC-alpha-infected cells. To assess the requirement of PKC-alpha for these PMA-induced changes, AdV-DN PKC-alpha or AdV betagal-infected NRVMs were stimulated with PMA. Without PMA, AdV-DN PKC-alpha had no effects on protein synthesis, P/D ratio, CSA, or shape vs. AdV betagal-infected NRVMs. PMA increased protein synthesis, P/D ratio, and CSA in AdV betagal-infected cells, but these parameters were significantly reduced in PMA-stimulated AdV-DN PKC-alpha-infected NRVMs. Overexpression of DN PKC-alpha enhanced PMA-induced cell elongation. Neither WT PKC-alpha nor DN PKC-alpha affected atrial natriuretic factor gene expression. Insulin-like growth factor-1 also induced nuclear translocation of endogenous PKC-alpha. PMA but not WT PKC-alpha overexpression induced ERK1/2 activation. However, AdV-DN PKC-alpha partially blocked PMA-induced ERK activation. Thus PKC-alpha is necessary for certain aspects of PMA-induced NRVM hypertrophy.
Collapse
Affiliation(s)
- Kalpana Vijayan
- Cardiovascular Institute, Loyola Univ. Medical Center, Bldg. 110, Rm. 5232, 2160 S. First Ave., Maywood, IL 60153, USA.
| | | | | | | |
Collapse
|
23
|
Yamaguchi O. Response of bladder smooth muscle cells to obstruction: signal transduction and the role of mechanosensors. Urology 2004; 63:11-6. [PMID: 15013647 DOI: 10.1016/j.urology.2003.12.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Bladder hypertrophy and detrusor overactivity are well-known bladder responses to outlet obstruction. Mechanical stretch stress is considered the trigger inducing these responses in the urodynamically overloaded bladder. Several studies using an in vitro model of mechanical stress demonstrate that repetitive stretch stimulation of bladder smooth muscle cells results in increased expression of a variety of growth factors and other specific proteins. In the bladder smooth muscle cell, stretch-activated ion channels (SACs) and protein kinase C (PKC) sarcolemmal proteins may function as sensors for external mechanical forces. In particular, SACs couple mechanical stress to activation of c-jun NH2-terminal kinase, which leads to a rapid induction of nuclear transcription factors. PKC also may involve an indirect or direct regulation of nuclear events. In addition, mechanical stress may induce the release of angiotensin II in an autocrine fashion. These factors in turn stimulate expression of specific gene-encoding proteins, such as heparin-binding epidermal growth factor-like growth factor, nerve growth factor, and an isomer of cyclooxygenase-2, all of which have the potential to contribute to structural and functional alterations in the bladder after obstruction.
Collapse
Affiliation(s)
- Osamu Yamaguchi
- Department of Urology, Fukushima Medical University, Fukushima City, Fukushima, Japan.
| |
Collapse
|
24
|
Gobeil F, Vazquez-Tello A, Marrache AM, Bhattacharya M, Checchin D, Bkaily G, Lachapelle P, Ribeiro-Da-Silva A, Chemtob S. Nuclear prostaglandin signaling system: biogenesis and actions via heptahelical receptors. Can J Physiol Pharmacol 2003; 81:196-204. [PMID: 12710534 DOI: 10.1139/y02-163] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Prostaglandins are ubiquitous lipid mediators that play pivotal roles in cardiovascular homeostasis, reproduction, and inflammation, as well as in many important cellular processes including gene expression and cell proliferation. The mechanism of action of these lipid messengers is thought to be primarily dependent on their interaction with specific cell surface receptors that belong to the heptahelical transmembrane spanning G protein-coupled receptor superfamily. Accumulating evidence suggests that these receptors may co-localize at the cell nucleus where they can modulate gene expression through a series of biochemical events. In this context, we have recently demonstrated that prostaglandin E2-EP3 receptors display an atypical nuclear compartmentalization in cerebral microvascular endothelial cells. Stimulation of these nuclear EP3 receptors leads to an increase of eNOS RNA in a cell-free isolated nuclear system. This review will emphasize these findings and describe how nuclear prostaglandin receptors, notably EP3 receptors, may affect gene expression, specifically of eNOS, by identifying putative transducing elements located within this organelle. The potential sources of lipid ligand activators for these intracellular sites will also be addressed. The expressional control of G-protein-coupled receptors located at the perinuclear envelope constitutes a novel and distinctive mode of gene regulation.
Collapse
Affiliation(s)
- Fernand Gobeil
- Department of Pharmacology, Université de Sherbrooke, 3001, 12th North Avenue, Fleurimont, Sherbrooke, QC J1H 5N4, Canada.
| | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Shahak H, Slotkin TA, Yanai J. Alterations in PKCgamma in the mouse hippocampus after prenatal exposure to heroin: a link from cell signaling to behavioral outcome. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2003; 140:117-25. [PMID: 12524182 DOI: 10.1016/s0165-3806(02)00607-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Administration of heroin to pregnant mice evokes neurochemical and behavioral deficits consequent to disruption of septohippocampal cholinergic innervation, notably involving desensitization of the ability of cholinergic receptors to activate PKC activity. The present study further evaluates whether desensitization occurs specifically for the PKCgamma isoform, the behaviorally relevant subtype, as compared to PKCalpha. Mice were exposed transplacentally to heroin on gestational days (GD) 9-18 via s.c. maternal injections (10 mg/kg per day). In young adulthood (50 days old), control offspring showed an increase in hippocampal cell membrane PKCgamma after incubation with the muscarinic cholinergic receptor agonist, carbachol, indicative of translocation from the cytosol. Prenatal exposure to heroin eliminated this response, whereas basal PKCgamma levels were unchanged. In contrast, PKCalpha, which is not related to heroin-induced behavioral deficits, did not show a loss of response. The present findings strongly point to abnormalities in the responsiveness of PKCgamma as a mechanism underlying the neurobehavioral teratogenicity of heroin.
Collapse
Affiliation(s)
- Halit Shahak
- The Ross Laboratory for Studies in Neural Birth Defects, Department of Anatomy and Cell Biology, The Hebrew University-Hadassah Medical School, P.O. Box 12272, 91120 Jerusalem, Israel
| | | | | |
Collapse
|
26
|
Cataldi A, Centurione L, Di Pietro R, Rapino M, Bosco D, Grifone G, Garaci F, Rana R. Protein kinase C zeta nuclear translocation mediates the occurrence of radioresistance in friend erythroleukemia cells. J Cell Biochem 2003; 88:144-51. [PMID: 12461784 DOI: 10.1002/jcb.10305] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Friend erythroleukemia cells require high doses (15 Gy) of ionizing radiation to display a reduced rate of proliferation and an increased number of dead cells. Since ionizing radiation can activate several signaling pathways at the plasma membrane which can lead to the nuclear translocation of a number of proteins, we looked at the intranuclear signaling system activated by Protein Kinases C, being this family of enzymes involved in the regulation of cell growth and death. Our results show an early and dose-dependent increased activity of zeta and epsilon isoforms, although PKC zeta is the only isoform significantly active and translocated into the nuclear compartment upon low (1.5 Gy) and high (15 Gy) radiation doses. These observations are concomitant and consistent with an increase in the anti-apoptotic protein Bcl-2 level upon both radiation doses. Our results point at the involvement of the PKC pathway in the survival response to ionizing radiation of this peculiar cell line, offering PKC zeta for consideration as a possible target of pharmacological treatments aimed at amplifying the effect of such a genotoxic agent.
Collapse
Affiliation(s)
- A Cataldi
- Dipartimento di Biomorfologia, Università G. D'Annunzio, Chieti, Italy.
| | | | | | | | | | | | | | | |
Collapse
|
27
|
Martelli AM, Bortul R, Tabellini G, Faenza I, Cappellini A, Bareggi R, Manzoli L, Cocco L. Molecular characterization of protein kinase C-alpha binding to lamin A. J Cell Biochem 2002; 86:320-30. [PMID: 12112001 DOI: 10.1002/jcb.10227] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Previous results from our laboratory have identified lamin A as a protein kinase C (PKC)-binding protein. Here, we have identified the regions of PKC-alpha that are crucial for this binding. By means of overlay assays and fusion proteins made of glutathione-S-transferase (GST) fused to elements of rat PKC-alpha, we have established that binding occurs through both the V5 region and a portion of the C2 region (i.e., the calcium-dependent lipid binding (CaLB) domain) of the kinase. In particular, we have found that amino acid 200-217 of the CaLB domain are essential for binding lamin A, as a synthetic peptide corresponding to this stretch of amino acids prevented the interaction between the CaLB domain and lamin A. We also show that the presence of four lysine residues of the CaLB domain (K205, K209, K211, and K213) was essential for the binding. We have determined that binding of elements of PKC-alpha to lamin A does not require the presence of cofactors such as phosphatidylserine (PS) and Ca(2+). We have also found that the binding site of lamin A for the CaLB domain of PKC-alpha is localized in the carboxyl-terminus of the lamin, downstream of amino acid 499. Our findings may prove to be important to clarify the mechanisms regulating PKC function within the nucleus and may also lead to the synthesis of isozyme-specific drugs to attenuate or reverse PKC-dependent nuclear signaling pathways important for the pathogenesis of cancer.
Collapse
Affiliation(s)
- Alberto M Martelli
- Dipartimento di Scienze Anatomiche Umane e Fisiopatologia dell'Apparato Locomotore, Sezione di Anatomia Umana, Cell Signaling Laboratory, Università di Bologna, via Irnerio 48, Italy.
| | | | | | | | | | | | | | | |
Collapse
|
28
|
Rosenberger U, Lehmann I, Weise C, Franke P, Hucho F, Buchner K. Identification of PSF as a protein kinase Calpha-binding protein in the cell nucleus. J Cell Biochem 2002; 86:394-402. [PMID: 12112008 DOI: 10.1002/jcb.10233] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Protein kinase C (PKC) isoforms are present in the cell nucleus in diverse cell lines and tissues. Since little is known about proteins interacting with PKC inside the cell nucleus, we used Neuro-2a neuroblastoma cells, in which PKCalpha is present in the nucleus, to screen for nuclear binding partners for PKC. Applying overlay assays, we detected several nuclear proteins which bind to PKCalpha. Specificity of binding was shown by its dependence on PKC activation by phorbol ester, calcium, and phosphatidylserine. The PKC-binding proteins were partially purified and analyzed by microsequencing and mass spectrometry. Four proteins could be identified: PTB-associated splicing factor (PSF), p68 RNA helicase, and the heterogeneous nuclear ribonucleoprotein (hnRNP) proteins A3 and L. In the case of PSF, binding to PKC could also be demonstrated in a GST-pull-down assay using GST-PKCalpha, expressed in insect cells. Phosphorylation experiments revealed that PSF is a weak in vitro substrate for PKCalpha.
Collapse
Affiliation(s)
- Uwe Rosenberger
- Freie Universität Berlin, Institut für Chemie-Biochemie, AG Neurochemie, Thielallee 63, 14195 Berlin, Germany
| | | | | | | | | | | |
Collapse
|
29
|
Tabellini G, Bortul R, Aluigi M, Billi AM, Bareggi R, Grill V, Narducci P, Martelli AM. Binding of elements of protein kinase C-alpha regulatory domain to lamin B1. Cell Signal 2002; 14:819-27. [PMID: 12135703 DOI: 10.1016/s0898-6568(02)00021-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Previous results from our laboratory have demonstrated that lamin B1 is a protein kinase C (PKC)-binding protein. Here, we have identified the regions of PKC-alpha that are important for this binding. By means of overlay assays and fusion proteins made of glutathione-S-transferase (GST) fused to elements of the regulatory domain of rat PKC-alpha, we have established that binding occurs through both the V1 region and a portion of the C2 region (i.e., the calcium-dependent lipid binding [CaLB] domain) of the kinase. In particular, we have found that amino acids 200-217 of the CaLB domain are essential for binding lamin B1, as a synthetic peptide corresponding to this stretch of amino acids prevented the interaction between the CaLB domain of PKC-alpha and lamin B1. In agreement with the results of other investigators, we have determined that binding of regulatory elements of PKC-alpha to lamin B1 does not require the presence of cofactors such as PS and Ca(2+). We have also found that the binding site of lamin B1 for PKC-alpha is localized in the carboxyl-terminus of the lamin. Our findings may prove to be important in shedding more light on the mechanisms that regulate PKC functions within the nuclear compartment and may also lead to the synthesis of isozyme-specific pharmacological tools to attenuate or reverse PKC-dependent nuclear signalling pathways important for the pathogenesis of cancer.
Collapse
Affiliation(s)
- Giovanna Tabellini
- Dipartimento di Morfologia Umana Normale, Università di Trieste, via Manzoni 16, 34138 Trieste, Italy
| | | | | | | | | | | | | | | |
Collapse
|
30
|
Harbers M, Nomura T, Ohno S, Ishii S. Intracellular localization of the Ret finger protein depends on a functional nuclear export signal and protein kinase C activation. J Biol Chem 2001; 276:48596-607. [PMID: 11591718 DOI: 10.1074/jbc.m108077200] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The Ret finger protein (RFP) was identified initially as an oncogene product and belongs to a family of proteins that contain a tripartite motif consisting of a RING finger, a B box, and a coiled-coil domain. RFP represses transcription by interacting with Enhancer of Polycomb and is localized to the cytoplasm or nucleus depending on the cell type. Here, we have identified the nuclear export signal (NES) located in the coiled-coil region of RFP. Mutation of this NES or treatment with leptomycin B abrogated the nuclear export of RFP in NIH3T3 cells. In addition, fusion of this NES to other nuclear proteins, such as yeast transcription factor Gal4, resulted in their release into the cytoplasm of NIH3T3 cells. Although the NES function of RFP in HepG2 cells is masked by another domain in RFP or by another protein, 12-O-tetradecanoylphorbol-13-acetate treatment or overexpression of constitutively active protein kinase Calpha (PKCalpha) abrogated masking, leading to the cytoplasmic localization of RFP. Furthermore, treatment of NIH3T3 cells with PKC inhibitors blocked the function of NES, resulting in nuclear localization of RFP. Thus, the nuclear export of RFP is regulated positively by PKC activation. However, RFP was not a direct substrate of PKC, and additional signaling pathways may be involved in the regulation of nuclear export of RFP.
Collapse
Affiliation(s)
- M Harbers
- RIKEN Tsukuba Institute and Core Research for Evolutionary Science and Technology (CREST) Project of Japan Science and Technology Corporation, 3-1-1 Koyadai, Tsukuba, Ibaraki
| | | | | | | |
Collapse
|
31
|
Valencia S, Hernández-Angeles A, Soria-Jasso LE, Arias-Montaño JA. Histamine H(1) receptor activation inhibits the proliferation of human prostatic adenocarcinoma DU-145 cells. Prostate 2001; 48:179-87. [PMID: 11494333 DOI: 10.1002/pros.1096] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Histamine stimulates cell proliferation in some tumor cell lines through the activation of H(1) receptors coupled to phosphoinositide hydrolysis. We therefore set out to study the presence of H(1) receptors in the prostate cancer cell line DU-145 and the effect of their stimulation on cell growth. METHODS The presence of histamine receptors was studied by radioligand binding. Phosphoinositide hydrolysis was assessed by measuring [(1)H]-inositol phosphate ([(1)H]-IPs) accumulation and changes in the intracellular concentration of free Ca(2+) ([Ca(2+)](i)). Proliferation was assessed by cell counting and by [(1)H]-thymidine incorporation. RESULTS DU-145 cells express H(1) receptors (110+/-14 fmol/mg of protein) whose stimulation results in [(1)H]-IPs accumulation (602+/-23% of basal, EC(50) 2.2+/-0.4 microM) and calcium mobilization (resting level 96+/-5 nM, Delta[Ca(2+)](i) 517+/-32 nM, EC(50) 6.2+/-0.1 microM). Incubation with histamine (100 microM, 24 hr) resulted in a decrease in both cell number and [(1)H]-thymidine incorporation, blocked by the H(1) antagonist mepyramine (1 microM). CONCLUSIONS Histamine inhibits the proliferation of DU-145 cells through the activation of H(1) receptors coupled to phosphoinositide hydrolysis.
Collapse
Affiliation(s)
- S Valencia
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados, México, D.F., Mexico
| | | | | | | |
Collapse
|
32
|
Abstract
Immunogold labeling of proteins in sections of embryos embedded in acrylate media provides an important analytical tool when the resolving power of the electron microscope is required to define sites of protein function. The protocol presented here was established to analyze the role and dynamics of the activated protein kinase C/Rack1 regulatory system in the patterning and outgrowth of limb bud mesenchyme. With minor changes, especially in the composition of the fixative solution, the protocol should be easily adaptable for the postembedding immunogold labeling of any other antigen in tissues of embryos of diverse species. Quantification of the labeling can be achieved by using electron microscope systems capable of supporting digital image analysis.
Collapse
Affiliation(s)
- W D Sierralta
- Max-Planck-Institut für experimentelle Endokrinologie, D-30603, Hannover, Germany. ,uchile.cl
| |
Collapse
|
33
|
Abstract
Our laboratory has previously reported that the exposure of smooth muscle cells (SMC) to the cyclic strain results in significant stimulation of protein kinase C (PKC) activity by translocating the enzyme from the cytosol to the particulate fraction. We now sought to examine the strain-induced translocation of individual PKC isoforms in SMC. Confluent bovine aortic SMC grown on collagen type I-coated plates were exposed to cyclic strain for up to 100 s at average 10% strain with 60 cycles/min. Immunoblotting analysis demonstrates that SMC express PKC-alpha, -beta and -zeta in both cytosolic and particulate fractions. Especially, PKC-alpha and -zeta were predominantly expressed in the cytosolic fraction. However, cyclic strain significantly (P < 0.05) increased PKC-alpha and -zeta in the particulate fraction and decreased in the cytosolic fraction. Thus, the cyclic strain-mediated stimulation of PKC activity in SMC may be due to the translocation of PKC-alpha and -zeta from the cytosolic to the particulate fraction. These results demonstrate that mechanical deformation causes rapid translocation of PKC isoforms, which may initiate a cascade of proliferation responses of SMC since NF-kappaB, which is involved in the cellular proliferation has been known to be activated by these PKC isoforms.
Collapse
Affiliation(s)
- O Han
- Department of Surgery, Yale University School of Medicine, New Haven, Connecticut 06510, USA
| | | | | | | |
Collapse
|
34
|
Anji A, Sullivan Hanley NR, Kumari M, Hensler JG. The role of protein kinase C in the regulation of serotonin-2A receptor expression. J Neurochem 2001; 77:589-97. [PMID: 11299321 DOI: 10.1046/j.1471-4159.2001.00261.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We have investigated in C6 glioma cells the involvement of protein kinase C (PKC) in the regulation of serotonin-(2A) receptor (5-HT(2A) receptor) expression by agonist treatment. Comparison of the time-courses of agonist-induced downregulation of receptor number and mRNA indicate that a decrease in the number of 5-HT(2A) receptor binding sites in response to serotonin (5-HT) treatment is preceded by a decrease in 5-HT(2A) receptor mRNA. This decrease in 5-HT(2A) receptor mRNA as a result of agonist exposure was not due to a change in the stability or half-life of the transcript. Pretreatment of cells with the PKC inhibitor bisindolylmaleimide blocked the decrease in 5-HT(2A) receptor mRNA levels, and attenuated the down-regulation of 5-HT(2A) receptor binding sites induced by treatment with 5-HT. Experiments performed with the PKC inhibitors calphostin C and Gö 6976 confirmed that PKC was involved in the regulation of 5-HT(2A) receptor mRNA by agonist and implicate the conventional subgroup of PKC isoforms. Western blot analysis, using isoform-specific anti-PKC antibodies showed that under our culture conditions C6 glioma cells express the conventional isoforms PKC alpha, PKC gamma, as well as the novel isoforms PKC delta, PKC epsilon, and the atypical isoforms PKC lambda and PKC iota. Upon treatment with 5-HT for 10 min levels of the conventional isoforms PKC alpha and PKC gamma increased in the nuclear fraction. Taken together, our results implicate PKC alpha and/or PKC gamma in the regulation of 5-HT(2A) mRNA receptor and binding sites in response to agonist treatment.
Collapse
Affiliation(s)
- A Anji
- Department of Pharmacology, University of Texas Health Science Center, San Antonio, Texas, USA
| | | | | | | |
Collapse
|
35
|
Bin W, Aksoy MO, Yang Y, Kelsen SG. IL-1beta enhances beta2-adrenergic receptor expression in human airway epithelial cells by activating PKC. Am J Physiol Lung Cell Mol Physiol 2001; 280:L675-9. [PMID: 11238007 DOI: 10.1152/ajplung.2001.280.4.l675] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Protein kinase C (PKC)-activated signal transduction pathways regulate cell growth and differentiation in many cell types. We have observed that interleukin (IL)-1beta upregulates beta2-adrenergic receptor (beta2-AR) density and beta2-AR mRNA in human airway epithelial cells (e.g., BEAS-2B). We therefore tested the hypothesis that PKC-activated pathways mediate IL-1beta-induced beta-AR upregulation. The role of PKC was assessed from the effects of 1) the PKC activator phorbol 12-myristate 13-acetate (PMA) on beta-AR density, 2) selective PKC inhibitors (calphostin C and Ro-31-8220) on beta-AR density, and 3) IL-1beta treatment on the cellular distribution of PKC isozymes. Recombinant human IL-1beta (0.2 nM for 18 h) increased beta-AR density to 213% of control values (P < 0.001). PMA (1 microM for 18 h) increased beta-AR density to 225% of control values (P < 0.005), whereas Ro-31-8220 and calphostin C inhibited the IL-1beta-induced upregulation of beta-AR in dose-dependent fashion. PKC isozymes detected by Western blotting included alpha, betaII, epsilon, mu, zeta, and lambda/iota. IL-1beta increased PKC-mu immunoreactivity in the membrane fraction and had no effect on the distribution of the other PKC isozymes identified. These data indicate that IL-1beta-induced beta-AR upregulation is mimicked by PKC activators and blocked by PKC inhibitors and appears to involve selective activation of the PKC-mu isozyme. We conclude that signal transduction pathways activated by PKC-mu upregulate beta2-AR expression in human airway epithelial cells.
Collapse
Affiliation(s)
- W Bin
- Pulmonary Division, Department of Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | | | | | | |
Collapse
|
36
|
Abstract
PKC isoenzymes were found to be involved in proliferation, antitumor drug resistance and apoptosis. Therefore, it has been tried to exploit PKC as a target for antitumor treatment. PKC alpha activity was found to be elevated, for example, in breast cancers and malignant gliomas, whereas it seems to be underexpressed in many colon cancers. So it can be expected that inhibition of PKC activity will not show similar antitumor activity in all tumors. In some tumors it seems to be essential to inhibit PKC to reduce growth. However, for inhibition of tumor proliferation it may be an advantage to induce apoptosis. In this case an activation of PKC delta should be achieved. The situation is complicated by the facts that bryostatin leads to the activation of PKC and later to a downmodulation and that the PKC inhibitors available to date are not specific for one PKC isoenzyme. For these reasons, PKC modulation led to many contradicting results. Despite these problems, PKC modulators such as miltefosine, bryostatin, safingol, CGP41251 and UCN-01 are used in the clinic or are in clinical evaluation. The question is whether PKC is the major or the only target of these compounds, because they also interfere with other targets. PKC may also be involved in apoptosis. Oncogenes and growth factors can induce cell proliferation and cell survival, however, they can also induce apoptosis, depending on the cell type or conditions in which the cells or grown. PKC participates in these signalling pathways and cross-talks. Induction of apoptosis is also dependent on many additional factors, such as p53, bcl-2, mdm2, etc. Therefore, there are also many contradicting results on PKC modulation of apoptosis. Similar controversial data have been reported about MDR1-mediated multidrug resistance. At present it seems that PKC inhibition alone without direct interaction with PGP will not lead to successful reversal of PGP-mediated drug efflux. One possibility to improve chemotherapy would be to combine established antitumor drugs with modulators of PKC. However, here also very contrasting results were obtained. Many indicate that inhibition, others, that activation of PKC enhances the antiproliferative activity of anticancer drugs. The problem is that the exact functions of the different PKC isoenzymes are not clear at present. So further investigations into the role of PKC isoenzymes in the complex and interacting signalling pathways are essential. It is a major challenge in the future to reveal whether modulation of PKC can be used for the improvement of cancer therapy.
Collapse
Affiliation(s)
- J Hofmann
- Institute of Medical Chemistry and Biochemistry, University of Innsbruck, A-6020 Innsbruck, Austria
| |
Collapse
|
37
|
Kotsonis P, Funk L, Prountzos C, Iannazzo L, Majewski H. Differential abilities of phorbol esters in inducing protein kinase C (PKC) down-regulation in noradrenergic neurones. Br J Pharmacol 2001; 132:489-99. [PMID: 11159699 PMCID: PMC1572566 DOI: 10.1038/sj.bjp.0703813] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. The ability of several phorbol ester protein kinase C (PKC) activators (phorbol 12, 13-dibutyrate, PDB; phorbol 12, 13-diacetate, PDA; and 12-deoxyphorbol 13-acetate, dPA) to down-regulate PKC was studied by assessing their effects on electrical stimulation-induced (S-I) noradrenaline release from rat brain cortical slices and phosphorylation of the PKC neural substrate B-50 in rat cortical synaptosomal membranes. 2. In cortical slices which were incubated for 20 h with vehicle, acute application of PDB, PDA and dPA (0.1 - 3.0 microM) enhanced the S-I noradrenaline release in a concentration-dependent manner to between 200 - 250% of control in each case. In slices incubated with PDB (1 microM for 20 h), subsequent acute application of PDB (0.1 - 3.0 microM) failed to enhance S-I release, indicating PKC down-regulation. However, in tissues incubated with PDA or dPA (3 microM) for 20 h, there was no reduction in the facilitatory effect of their respective phorbol esters or PDB (0.1 - 3.0 microM) when acutely applied, indicating that PKC was not down-regulated. This was confirmed using Western blot analysis which showed that PDB (1 microM for 20 h) but not PDA (3 microM for 20 h) caused a significant reduction in PKCalpha. 3. Incubation with PDB for 20 h, followed by acute application of PDB (3 microM) failed to increase phosphorylation of B-50 in synaptosomal membranes, indicating down-regulation. In contrast, tissues incubated with PDA or dPA for 20 h, acute application of their respective phorbol ester (10 microM) or PDB (3 microM) induced a significant increase in B-50 phosphorylation. 4. Acutely all three phorbol esters elevate noradrenaline release to about the same extent, yet PDA and dPA have lower affinities for PKC compared to PDB, suggesting unique neural effects for these agents. This inability to cause functional down-regulation of PKC extends their unusual neural properties. Their neural potency and lack of down-regulation may be related to their decreased lipophilicity compared to other phorbol esters. 5. We suggest that PKC down-regulation appears to be related to binding affinity, where agents with high affinity, irreversibly insert PKC into artificial membrane lipid and generate Ca(2+)-independent kinase activity which degrades and deplete PKC. We suggest that this mechanism may also underlie the ability of PDB to down-regulate PKC in nerve terminals, in contrast to PDA and dPA.
Collapse
Affiliation(s)
- P Kotsonis
- Novartis Institute for Medical Sciences, London WC1E 6BN
| | - L Funk
- Abteilung Innere Medizin IV, Universitätsklinikum Freiburg, Freiburg 79106, Germany
| | - C Prountzos
- Department of Medical Laboratory Sciences, RMIT University, Melbourne, Victoria 3001, Australia
| | - L Iannazzo
- Department of Medical Laboratory Sciences, RMIT University, Melbourne, Victoria 3001, Australia
| | - H Majewski
- Department of Medical Laboratory Sciences, RMIT University, Melbourne, Victoria 3001, Australia
- Author for correspondence:
| |
Collapse
|
38
|
Maraldi NM, Zini N, Santi S, Riccio M, Falconi M, Capitani S, Manzoli FA. Nuclear domains involved in inositol lipid signal transductionmaltese cross. ADVANCES IN ENZYME REGULATION 2000; 40:219-53. [PMID: 10828353 DOI: 10.1016/s0065-2571(99)00032-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- N M Maraldi
- Institute of Cytomorphology, CNR Chieti and Bologna, c/o IOR, Bologna, Italy
| | | | | | | | | | | | | |
Collapse
|
39
|
Wagner S, Harteneck C, Hucho F, Buchner K. Analysis of the subcellular distribution of protein kinase Calpha using PKC-GFP fusion proteins. Exp Cell Res 2000; 258:204-14. [PMID: 10912802 DOI: 10.1006/excr.2000.4925] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
One important factor for the determination of the specific functions of protein kinase C (PKC) isoforms is their specific subcellular localization. In NIH 3T3 fibroblasts phorbol esters induce translocation of PKCalpha to the plasma membrane and the nucleus. In order to investigate PKCalpha's subcellular distribution and especially its nuclear accumulation in more detail we used fusion proteins consisting of PKCalpha and the green fluorescent protein (GFP). Purified GFP-PKCalpha from baculovirus-infected insect cells undergoes nuclear accumulation without any further stimuli in digitonin-permeabilized cells. Interestingly, permeabilization appears to be a trigger for PKCalpha's nuclear translocation, since the fusion protein also translocates to the nucleus in transiently transfected cells following permeabilization. This suggests that PKCalpha has a high nuclear binding capacity even in the case of large protein amounts. In contrast to endogenous PKCalpha, overexpressed GFP-PKCalpha as well as overexpressed PKCalpha itself translocates mainly to the plasma membrane and only to a smaller extent to the nucleus following stimulation with phorbol ester. Use of fusion proteins of GFP and different mutants of PKCalpha enabled determination of motifs involved PKCalpha's subcellular distribution: A25E and K368R point mutations of PKCalpha showed enhanced affinity for the plasma membrane, whereas sequences within the regulatory domain probably confer PKCalpha's nuclear accumulation.
Collapse
Affiliation(s)
- S Wagner
- Freie Universität Berlin, Institut für Chemie, Biochemie, Germany
| | | | | | | |
Collapse
|
40
|
Umar S, Sellin JH, Morris AP. Increased nuclear translocation of catalytically active PKC-zeta during mouse colonocyte hyperproliferation. Am J Physiol Gastrointest Liver Physiol 2000; 279:G223-37. [PMID: 10898766 DOI: 10.1152/ajpgi.2000.279.1.g223] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Protein kinase (PK) C-zeta is implicated in the control of colonic epithelial cell proliferation in vitro. However, less is known about its physiological role in vivo. Using the transmissible murine colonic hyperplasia (TMCH) model, we determined its expression, subcellular localization, and kinase activity during native crypt hyperproliferation. Enhanced mitosis was associated with increased cellular 72-kDa holoenzyme (PKC-zeta, 3.2-fold), 48-kDa catalytic subunit (PKM-zeta, 3- to 9-fold), and 24-kDa membrane-bound fragment (M(f)-zeta, >10-fold) expression. Both PKC-zeta and PKM-zeta exhibited intrinsic kinase activity, and substrate phosphorylation increased 4.5-fold. No change in cellular PKC-iota/PKM-iota expression occurred. The subcellular distribution of immunoreactive PKC-zeta changed significantly: neck cells lost their basal subcellular pole filamentous staining, whereas proliferating cell nuclear antigen-positive cells exhibited elevated cytoplasmic, lateral membrane, and nuclear staining. Subcellular fractionation revealed increased PKC-zeta and PKM-zeta expression and activity within nuclei, which preferentially accumulated PKM-zeta. These results suggest separate cellular and nuclear roles, respectively, for PKC-zeta in quiescent and mitotically active colonocytes. PKM-zeta may specifically act as a modulator of proliferation during TMCH.
Collapse
Affiliation(s)
- S Umar
- Department of Integrative Biology, Pharmacology, and Physiology, University of Texas Health Science Center at Houston, Medical School, 77030, USA
| | | | | |
Collapse
|
41
|
Skarpen E, Lindeman B, Thoresen GH, Guren TK, Oksvold MP, Christoffersen T, Huitfeldt HS. Impaired nuclear accumulation and shortened phosphorylation of ERK after growth factor stimulation in cultured hepatocytes from rats exposed to 2-acetylaminofluorene. Mol Carcinog 2000; 28:84-96. [PMID: 10900465 DOI: 10.1002/1098-2744(200006)28:2<84::aid-mc4>3.0.co;2-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The hepatic carcinogen 2-acetylaminofluorene (AAF) exerts its effect as a tumor promoter by mitoinhibition of normal hepatocytes. Initiated cells proliferate selectively and develop into preneoplastic foci and subsequently into carcinomas. To study whether some of the mitoinhibitory effects of AAF could be attributed to an influence on intracellular signal transduction, growth factor signaling was studied in cultured hepatocytes from rats fed AAF for 7 d. Activation through the epidermal growth factor receptor (EGFR) was used to probe possible changes in downstream mitogenic signaling mechanisms. The proliferative response to epidermal growth factor (EGF), measured as proliferating cell nuclear antigen expression and thymidine incorporation, was almost completely inhibited in hepatocytes exposed to AAF. Neither EGFR protein levels nor EGF binding was notably altered in AAF-exposed hepatocytes as opposed to normal hepatocytes. The initial tyrosine phosphorylation of EGFR and downstream activation of Sos, Raf-1, and extracellular signal-regulated protein kinase (ERK) were similar in AAF-treated and control hepatocytes. Even though ERK phosphorylation was unaffected, a remarkable (80%) reduction of ERK nuclear accumulation was observed in AAF-exposed hepatocytes immediately after mitogen stimulation. EGFR tyrosine phosphorylation and downstream signaling lasted 6 h in control cells versus 2 h in AAF-exposed hepatocytes. We previously demonstrated that AAF inhibits the growth factor-dependent induction of cyclin D1 and arrests hepatocyte cell-cycle progression before the p21/CIP1-controlled DNA-damage check point. The present data indicate that the DNA-damaging carcinogen AAF induces growth inhibition by a distinct inhibition of ERK nuclear accumulation after mitogen stimulation. Inhibition of intracellular signal transduction may represent a novel mechanism of growth arrest. Mol. Carcinog. 28:84-96, 2000.
Collapse
Affiliation(s)
- E Skarpen
- Laboratory for Toxicopathology, Institute of Pathology, The National Hospital, University of Oslo, Oslo, Norway
| | | | | | | | | | | | | |
Collapse
|
42
|
Krunkosky TM, Fischer BM, Martin LD, Jones N, Akley NJ, Adler KB. Effects of TNF-alpha on expression of ICAM-1 in human airway epithelial cells in vitro. Signaling pathways controlling surface and gene expression. Am J Respir Cell Mol Biol 2000; 22:685-92. [PMID: 10837365 DOI: 10.1165/ajrcmb.22.6.3925] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Signaling pathways associated with tumor necrosis factor (TNF)-alpha-induced intercellular adhesion molecule 1 (ICAM-1) surface and gene expression were investigated in well differentiated normal human bronchial epithelial (NHBE) cells in air-liquid interface primary culture. Cells were exposed to human recombinant TNF-alpha (hrTNF-alpha; 0.015 to 150 ng/ml [specific activity, 2.86 x 10(7) U/mg]). TNF-alpha enhanced ICAM-1 surface expression (measured by flow cytometry) and steady-state messenger RNA (mRNA) levels (assessed by Northern hybridization) in concentration- and time-dependent manners. TNF-alpha-induced ICAM-1 surface and gene expression were both blocked by the RNA polymerase II inhibitor actinomycin D (0.1 microg/ml), and surface expression was attenuated by a neutralizing monoclonal antibody directed against the TNF-alpha receptor p55 (TNF-RI). The intracellular signaling pathway leading to enhanced expression appeared to involve activation of a phospholipase C that hydrolyzes phosphatidylcholine (PC-PLC) because D609, a specific PC-PLC inhibitor, attenuated TNF-alpha-induced increases in production of diacyl-glycerol (DAG), a hydrolysis product of PC-PLC, and also attenuated TNF-alpha enhancement of ICAM-1 surface and gene expression. Because DAG formed by action of PC-PLC can activate protein kinase C (PKC), involvement of PKC was investigated. The specific PKC inhibitor calphostin C blocked both surface and gene expression of ICAM-1 in response to TNF-alpha in a concentration-dependent manner. Finally, TNF-alpha stimulated binding of p65 and/or c-rel complexes to the nuclear factor (NF)-kappaB consensus binding site found on the ICAM-1 promoter, and binding of these complexes was inhibited by D609. The results support the following pathway, whereby TNF-alpha enhances expression of ICAM-1 in NHBE cells: TNF-alpha --> TNF-RI --> PC-PLC --> DAG --> PKC --> (NF-kappaB?) --> ICAM-1 mRNA --> ICAM-1 surface expression.
Collapse
Affiliation(s)
- T M Krunkosky
- Department of Anatomy, Physiological Sciences, and Radiology, College of Veterinary Medicine, North Carolina State University, Raleigh 27606, USA
| | | | | | | | | | | |
Collapse
|
43
|
Albi E, Viola Magni M. Phosphatidylcholine-dependent phospholipase C in rat liver chromatin. Biochem Biophys Res Commun 1999; 265:640-3. [PMID: 10600474 DOI: 10.1006/bbrc.1999.1710] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Phosphatidylcholine-dependent phospholipase C is an enzyme which hydrolyses phosphatidylcholine giving origin to diacylglicerol and phosphorylcholine. Diacylglicerol has many effect and activates also protein kinase C. Since the presence of protein kinase C in the hepatocyte nuclei and the existence of a phospholipidic fraction in the chromatin have been demonstrated, we investigated if phosphatidylcholine-dependent phospholipase C could be present in the nuclei. The results obtained have shown the presence of this enzyme in the chromatin fraction which differs with respect to that of nuclear membrane in pH and Km. The activity has been also evaluated during liver regeneration. In the chromatin an increase of activity has been shown 12 h and 30 h after hepatectomy, i.e. at the beginning of hepatocyte S-phase. No similar behaviour has been observed in the nuclear membrane. It has been suggested that diacylglicerol, produced by the hydrolysis of chromatin phosphatidylcholine, may have a role in initiating DNA synthesis through the prolonged activation of the nuclear form of protein kinase C.
Collapse
Affiliation(s)
- E Albi
- Facoltà di Medicina e Chirurgia, Università degli Studi di Perugia, Policlinico Monteluce, Perugia, 06100, Italy
| | | |
Collapse
|
44
|
Kingsley-Kallesen ML, Kelly D, Rizzino A. Transcriptional regulation of the transforming growth factor-beta2 promoter by cAMP-responsive element-binding protein (CREB) and activating transcription factor-1 (ATF-1) is modulated by protein kinases and the coactivators p300 and CREB-binding protein. J Biol Chem 1999; 274:34020-8. [PMID: 10567368 DOI: 10.1074/jbc.274.48.34020] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Transcription of the transforming growth factor-beta2 (TGF-beta2) gene is dependent on a cAMP-response element/activating transcription factor (CRE/ATF) site that is bound by CREB and ATF-1 as well as an E-box motif that is bound by upstream stimulatory factors 1 and 2 (USF1 and USF2). To identify additional factors involved in the expression of the TGF-beta2 gene, we employed F9 embryonal carcinoma (EC) cells, which express TGF-beta2 only after the cells differentiate. We show that overexpression of the transcription factors, CREB, ATF-1, USF1, and USF2 dramatically increases TGF-beta2 promoter activity in F9-differentiated cells. We further show that the coactivators p300 and CBP up-regulate the TGF-beta2 promoter when CREB and ATF-1 are expressed in conjunction with protein kinases that phosphorylate CREB on serine 133 and ATF-1 on serine 63. Importantly, we identify the presence of serine 133-phosphorylated CREB in the nucleus of F9-differentiated cells but not in the nucleus of F9 EC cells. This phosphorylated form is present in whole cell extracts of both the parental and differentiated cells, suggesting that nuclear accumulation of serine 133-phosphorylated CREB is regulated during differentiation of F9 EC cells and is likely to play an important role in the activation of the TGF-beta2 gene.
Collapse
Affiliation(s)
- M L Kingsley-Kallesen
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska 68198-6805, USA
| | | | | |
Collapse
|
45
|
Slosberg ED, Klein MG, Yao Y, Han EK, Schieren I, Weinstein IB. The alpha isoform of protein kinase C mediates phorbol ester-induced growth inhibition and p21cip1 induction in HC11 mammary epithelial cells. Oncogene 1999; 18:6658-66. [PMID: 10597271 DOI: 10.1038/sj.onc.1203083] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
To clarify the roles of specific isoforms of PKC in regulating growth and cell cycle progression of the HC11 mammary epithelial cell line, we investigated the effects of activating endogenous PKC isoforms with the phorbol ester tumor promoter TPA, and also the effects of TPA on genetically engineered cells containing increased levels of individual PKC isoforms. We found that TPA treatment of HC11 cells induced a transient cell cycle arrest in G0/G1. Western blot analyses of the TPA treated cells provided evidence that the endogenous PKC alpha present in these cells mediated these effects. Indeed, derivatives of the HC11 cell line that inducibly overexpress an exogenous PKC alpha or ectopic PKC beta 1 exhibited more marked growth inhibition by TPA than control cells. Immunohistochemical staining of cells following treatment with TPA revealed selective translocation of PKC alpha into the nucleus, whereas PKC beta 1 remained in the cytoplasm. The transient arrest of HC11 cells following treatment with TPA was associated with marked induction of both p21cip1 mRNA and protein. This induction was exaggerated in the derivatives that overexpressed either PKC alpha or PKC beta 1. Therefore, in mouse mammary epithelial cells activation of the endogenous PKC alpha can transiently arrest cells in G0/G1 which may be due, at least in part, to induction of the transcription of p21cip1.
Collapse
Affiliation(s)
- E D Slosberg
- Herbert Irving Comprehensive Cancer Center, Columbia University, New York, NY 10032, USA
| | | | | | | | | | | |
Collapse
|
46
|
Abstract
An increasing body of evidence shows that many of the key inositol lipids and enzymes responsible for their metabolism reside in nuclei. Moreover, the association of the nuclear phosphoinositide cycle with progression through the cell cycle and commitment toward differentiation has built a wider picture of the implications of phosphoinositides in the control of nuclear functions. This article reviews a central aspect of inositide nuclear signaling, i.e., the spatial organization of the signaling system within the nucleus in relationship to the nuclear organization in functional domains. Most of the evidence obtained with a variety of confocal and electron microscopy immunocytochemical techniques indicates that the phosphoinositides, the enzymes required for their synthesis and hydrolysis, and the targets of the lipid second messengers are localized at ribonucleoprotein structures involved in the transcript processing in the interchromatin domains. These findings demonstrate that nuclear inositol lipids exist in a nonmembranous form, linked to structural nuclear proteins of the inner nuclear matrix. They also suggest that the inositol signaling in the nucleus is completely independent of that at the cell surface and that it probably preceded in evolution the systems that are present at the cytoskeletal and cell membrane level.
Collapse
Affiliation(s)
- N M Maraldi
- Institute of Normal and Pathological Cytomorphology, C.N.R., Laboratory of Cell Biology, IOR, Bologna, Italy.
| | | | | | | |
Collapse
|
47
|
Osborn MT, Berry A, Ruberu MS, Ning B, Bell LM, Chambers TC. Phorbol ester induced MDR1 expression in K562 cells occurs independently of mitogen-activated protein kinase signaling pathways. Oncogene 1999; 18:5756-64. [PMID: 10523856 DOI: 10.1038/sj.onc.1202943] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The MDR1 gene encoding the multidrug pump P-glycoprotein is transcriptionally activated in response to diverse extracellular stimuli, including the tumor promoting phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA). However, the signal transduction pathway responsible is unknown. Downstream of protein kinase C (PKC), the effects of TPA are often mediated by the Raf-1/MEK/ERK mitogen-activated protein kinase (MAPK) cascade, and Raf-1 has been implicated in MDR1 induction by serum and mitogens. Therefore, we examined the potential role of MAPK activation in TPA-mediated MDR1 induction in human leukemia K562 cells. MDR1 mRNA expression was significantly increased by TPA in the concentration range of 4 - 100 nM, with a maximal response 5 - 10 h after TPA addition. TPA-mediated MDR1 induction was inhibited by several PKC inhibitors including staurosporine, H7 and calphostin C. TPA stimulated the subcellular translocation of PKCalpha from the cytosol to the membrane and nucleus but did not affect other PKC isozymes. TPA also activated the Raf1/MEK/ERK cascade and activated another MAPK member, p38, but not JNK. In order to determine the potential role of MAPKs in MDR1 induction by TPA, specific inhibitors were utilized. The MEK inhibitor PD 098059, as well as the PKC inhibitors, completely blocked TPA-mediated ERK activation. However, under identical conditions, MDR1 induction by TPA was completely unaffected by PD 098059. Furthermore, SB 202190, which effectively inhibited TPA-mediated p38 activation, failed to inhibit TPA-induced MDR1 mRNA expression. These data demonstrate that MDR1 induction by TPA occurs via a PKC-dependent mechanism that operates independently of ERK, p38 or JNK pathways, and thus have important implications for understanding the mechanisms of MDR1 induction by extracellular stimuli.
Collapse
Affiliation(s)
- M T Osborn
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA
| | | | | | | | | | | |
Collapse
|
48
|
Roodsari FS, Wu D, Pum GS, Hajdu J. A New Approach to the Stereospecific Synthesis of Phospholipids. The Use of l-Glyceric Acid for the Preparation of Diacylglycerols, Phosphatidylcholines, and Related Derivatives. J Org Chem 1999. [DOI: 10.1021/jo990414e] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Farzaneh S. Roodsari
- Department of Chemistry, California State University, Northridge, Northridge, California 91330-8262
| | - Dongpei Wu
- Department of Chemistry, California State University, Northridge, Northridge, California 91330-8262
| | - Gregory S. Pum
- Department of Chemistry, California State University, Northridge, Northridge, California 91330-8262
| | - Joseph Hajdu
- Department of Chemistry, California State University, Northridge, Northridge, California 91330-8262
| |
Collapse
|
49
|
Murphy TV, Prountzos C, Kotsonis P, Iannazzo L, Majewski H. Structural determinants of phorbol ester binding in synaptosomes: pharmacokinetics and pharmacodynamics. Eur J Pharmacol 1999; 381:77-84. [PMID: 10528137 DOI: 10.1016/s0014-2999(99)00540-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The present study used structurally distinct phorbol esters to investigate the relationship between their pharmacokinetics of binding to protein kinase C (PKC) in rat brain cortex synaptosomes, their affinity for PKC in synaptosomes and ability to enhance noradrenaline release from rat brain cortex. Affinity binding studies using [3deoxyphorbol 13-tetradecanoate (dPT)=PDB&z. Gt;12-deoxyphorbol 13-acetate (dPA)=phorbol 12,13-diacetate (PDA). In intact synaptosomes PDB, dPA and PDA rapidly displaced bound [3H]PDB whereas PMA and dPT were comparatively slow. However, the displacement rates for all the phorbol esters were equally rapid in synaptosomal membranes or synaptosomes permeabilised with Staphylococcus alpha-toxin. These results suggest that the lipophilic phorbol esters (dPT and PMA) are slower to displace [3H]PDB binding because they are hindered by the plasma membrane. In brain cortex slices it was found that the rate of displacement of [3H]PDB binding was closely correlated with the degree of elevation of transmitter noradrenaline release. Thus kinetic characteristics may determine biological responses and this may be particularly evident in events which occur rapidly or where there is fast counter-regulation.
Collapse
Affiliation(s)
- T V Murphy
- Prince Henry's Institute of Medical Research, P.O. Box 5152, Clayton, 3168 Victoria, Australia
| | | | | | | | | |
Collapse
|
50
|
|