• Title/Summary/Keyword: Protein phosphatase 4

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A Novel Calcineurin-interacting Protein, CNP-3, Modulates Calcineurin Deficient Phenotypes in Caenorhabditis elegans

  • Kim, Yun Hee;Song, Hyun-Ok;Ko, Kyung Min;Singaravelu, Gunasekaran;Jee, Changhoon;Kang, Junsu;Ahnn, Joohong
    • Molecules and Cells
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    • v.25 no.4
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    • pp.566-571
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    • 2008
  • Calcineurin (Cn) is a calcium/calmodulin-dependent serine/threonine protein phosphatase that has diverse functions in different cell types and organisms. We screened proteins interacting with the C. elegans CnA homolog, TAX-6, by the yeast two-hybrid system. CNP-3 (Calcineurin interacting protein-3) is a novel protein that physically interacts with the catalytic domain of TAX-6. It is strongly expressed in the nuclei of intestine, hypodermis, dorsal uterine regions and spermatheca. Expression begins around the 60-cell stage and proceeds during all larval stages and the adult. To elucidate the biological function of cnp-3 we isolated a cnp-3 deletion mutant. Since CNP-3 binds CnA, we looked at factors associated with calcineurin loss-of-function mutants, such as brood size, body size, serotonin- and levamisole-mediated egg-laying behavior. The cnp-3(jh145) single mutant had no gross defects compared to wild-type animal. However, the phenotypes of the double mutants, tax-6(p675);cnp-3(jh145) and cnb-1(jh103);cnp-3(jh145), were more severe in terms of brood size, body size and serotonin-mediated egg-laying defects than tax-6(p675) and cnb-1(jh103), respectively. These results suggest that dysfunction of cnp-3 enhances certain calcineurin loss-of-function phenotypes in C. elegans.

Studies on Intracellular Regulatory Proteins of Pancreatic Exocrine Secretion (이자효소 분비에 관여하는 세포 내 조절 단백에 대한 연구)

  • Chung, Ku-Yong;Choi, Jae-Won;Choi, Hong-Soon;Kim, Kyung-Hwan
    • The Korean Journal of Pharmacology
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    • v.32 no.2
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    • pp.243-257
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    • 1996
  • CCK and cholinergic agonist stimulate enzyme release from the pancreatic acini via G-protein-mediated activation of phospholipase C, In contrast secretin and related peptides increase the level of cAMP and activate cAMP-dependent protein kinase. Camostat, a synthetic protease inhibitor, causes pancreatic hypertrophy and hyperplasia by increasing the CCK release. In this study, the secretagogue-induced changes of intracellular proteins were examined in the dispersed pancreatic acini of rats with or without camostat treatment. Camostat(FOY-305, 200 mg/kg, p.o.) was given for 4 days twice daily and the dispersed acini were prepared at 12 bouts after last treatment. The profiles of Intracellular phosphoproteins were analyzed by two-dimensional gel electrophoresis after incubating the acini with $^{32}P$. The amylase release from the dispersed acini was measured. The pancreatic weight was increased to 126% of control, while amylase activity per mg acinar protein decreased to 41% of control, The maximum response of amylase release from dispersed acini to CCK-8 or carbachol was markedly decreased(65% or 46% of control, respectively). The group of intracellular proteins(24 kD, pI $4.5{\sim}8.5$) was increased in quantity by camostat. CCK-8 or secretin increased phosphorylation of a protein(34 kD, pI 4.7) in camostat-treated as well as control rats. CCK-8 increased tyrosine phosphoryiation in the acini of control rats. However, in camostat-treated rats, the basal level of tyrosine phosphorylation was increased and it was rather decreased by CCK-8. Secretin had no effect on the level of tyrosine phosphorylation in acini. These results indicate that both phospholipase C and adenylate cyclase induce phosphorylation of an intracellular acinar protein(34 kD, pI 4.7) and camostat treatment increases the basal level of tyrosine phosphorylation in acinar cells. And these results suggest that not only serine/threonine protein kinase but also protein tyrosine kinase/phosphatase are involved in the process of CCK receptor mediated stimulation-secrelion coupling.

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A Receptor Tyrosine Kinase Inhibitor, Dovitinib (TKI-258), Enhances BMP-2-Induced Osteoblast Differentiation In Vitro

  • Lee, Yura;Bae, Kyoung Jun;Chon, Hae Jung;Kim, Seong Hwan;Kim, Soon Ae;Kim, Jiyeon
    • Molecules and Cells
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    • v.39 no.5
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    • pp.389-394
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    • 2016
  • Dovitinib (TKI258) is a small molecule multi-kinase inhibitor currently in clinical phase I/II/III development for the treatment of various types of cancers. This drug has a safe and effective pharmacokinetic/pharmacodynamic profile. Although dovitinib can bind several kinases at nanomolar concentrations, there are no reports relating to osteoporosis or osteoblast differentiation. Herein, we investigated the effect of dovitinib on human recombinant bone morphogenetic protein (BMP)-2-induced osteoblast differentiation in a cell culture model. Dovitinib enhanced the BMP-2-induced alkaline phosphatase (ALP) induction, which is a representative marker of osteoblast differentiation. Dovitinib also stimulated the translocation of phosphorylated Smad1/5/8 into the nucleus and phosphorylation of mitogen-activated protein kinases, including ERK1/2 and p38. In addition, the mRNA expression of BMP-4, BMP-7, ALP, and OCN increased with dovitinib treatment. Our results suggest that dovitinib has a potent stimulating effect on BMP-2-induced osteoblast differentiation and this existing drug has potential for repositioning in the treatment of bone-related disorders.

Ceramide-Mediated Cell Death Was Accompanied with Changes of c-Myc and Rb Protein

  • Moon, Soon-Ok;Lee, Jin-Woo
    • BMB Reports
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    • v.31 no.4
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    • pp.333-338
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    • 1998
  • The sphingomyelin cycle and ceramide generation have been recognized as potential growth suppression signals in mammalian cells. Ceramide has been shown to induce differentiation, cell growth arrest, senescence, and apoptosis. Although the intracelluar target for the action of ceramide remains unknown, recent studies have demonstrated the role of cytosolic ceramideactivated protein phosphatase(CAPP). In this study, the cytotoxic effect of C2-ceramide, a synthetic cellpermeable ceramide analog, on HEp-2 cells and the mechanism by which ceramide induces cell death were investigated. The addition of exogenous C2-ceramide resulted in a concentration dependent cell death. Okadaic acid, a potent inhibitor of CAPP, enhanced ceramide-mediated cell death, which suggests that CAPP is not involved in this process. To understand the mechanism of action of ceramide, we studied the relationship between ceramide and c-Myc and pRb which are defined components of cell growth regulation. Western blot analyses revealed that C2-ceramide (10${\mu}M$) induced c-Myc down-regulation, but there were no significant changes in pRb. However, treatment of okadaic acid (10 nM) enhanced c-Myc and pRb down-regulation. Reduction of the amount of c-Myc and pRb occurred during HEp-2 cell death. These results suggest that the cytotoxic effect of ceramide in HEp-2 cells may not be mediated through the action of CAPP and that the downstream target for ceramide is c-Myc and pRb.

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Low-Intensity Pulsed Ultrasound Promotes BMP9 Induced Osteoblastic Differentiation in Rat Dedifferentiated Fat Cells

  • Fumiaki Setoguchi;Kotaro Sena;Kazuyuki Noguchi
    • International Journal of Stem Cells
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    • v.16 no.4
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    • pp.406-414
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    • 2023
  • Dedifferentiated fat cells (DFATs) isolated from mature adipocytes have a multilineage differentiation capacity similar to mesenchymal stem cells and are considered as promising source of cells for tissue engineering. Bone morphogenetic protein 9 (BMP9) and low-intensity pulsed ultrasound (LIPUS) have been reported to stimulate bone formation both in vitro and in vivo. However, the combined effect of BMP9 and LIPUS on osteoblastic differentiation of DFATs has not been studied. After preparing DFATs from mature adipose tissue from rats, DFATs were treated with different doses of BMP9 and/or LIPUS. The effects on osteoblastic differentiation were assessed by changes in alkaline phosphatase (ALP) activity, mineralization/calcium deposition, and expression of bone related genes; Runx2, osterix, osteopontin. No significant differences for ALP activity, mineralization deposition, as well as expression for bone related genes were observed by LIPUS treatment alone while treatment with BMP9 induced osteoblastic differentiation of DFATs in a dose dependent manner. Further, co-treatment with BMP9 and LIPUS significantly increased osteoblastic differentiation of DFATs compared to those treated with BMP9 alone. In addition, upregulation for BMP9-receptor genes was observed by LIPUS treatment. Indomethacin, an inhibitor of prostaglandin synthesis, significantly inhibited the synergistic effect of BMP9 and LIPUS co-stimulation on osteoblastic differentiation of DFATs. LIPUS promotes BMP9 induced osteoblastic differentiation of DFATs in vitro and prostaglandins may be involved in this mechanism.

Effect of Ethanol Intake on Blood Component in Broiler Chicks (알콜섭취가 성장기 닭의 혈액성분에 미치는 영향)

  • Kho, Jin-Bog;Oh, Hyong-Kun;Jung, Bok-Mi;Kim, Jae-Young;Ko, Young-Du
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.17 no.4
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    • pp.336-340
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    • 1988
  • This study was performed to investigate the influence of mixtures of 0(control), 1, 2 and 3% ethanol and water respectively on growth and various blood parameters of growing broiler chicks. At the end of the 7 weeks' experiment, body weight gain in 1% ethanol group and liver weight in 3% ethanol group were significantly higher than those of control group. It was found that the levels of red blood cell, hemoglobin, hematocrit, and serum protein were within normal ranges. Serum GOT and r-GTP activities were significantly increased in 2 and 3% ethanol groups compared with those in control group. But serum CPT activity was slightily decreased in all ethanol groups. Serum LDH activity was increased in all ethanol groups compared with that In control group. Serum alkaline phosphatase was not affected by the ethanol. Serum glucose concentration in 3% ethanol group was significantly lower than that in control group.

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Alcohol Ingestion Increases Lung Injury Induced by Cyclohexane (알코올 섭취 유무에 따른 cyclohexane의 폐 독성)

  • Kim, Byung-Ryul;Lee, Sang-Hee;Cho, Hyun-Gug
    • Applied Microscopy
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    • v.35 no.2
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    • pp.81-87
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    • 2005
  • To evaluate the effects of ingestion of alcoholic drinks on the toxicities of industrial compounds, cyclohexane (CH) was intraperitoneally administrated to rats (1.56 g/kg body weght), which had been ingested 15% ethanol for up to 6 weeks, 4 times by once a day and every other day. Following the last treatment of ethanol or CH, blood and lung tissues were collected during 24 hours prior to sacrifice of animals. Comparing with the control group, the lung weight per body weight (%) and the protein content in bronchoalveolar lavage fluid were increased in the ethanol-pretreated group, and the glucose-6-phosphatase activity in lung tissues was decreased in the CH-treated group. In a morphological observations, pulmonary embolus were found in the CH-treated group, whereas a partial pulmonary atelectasis and a much increase in pulmonary embolus were shown in the CH-treated group after pretreated with ethanol for 6 weeks. In conclusion, these results indicate that ethanol pretreatment could enhance CH metabolism and that CH treatment with ethanol pretreatment could induce lung injury due to the increased CH metabolism.

Osteoblastogenesis and osteolysis in the Zucker Diabetic Sprague Dawley rat humerus head

  • Gcwalisile Frances Dlamini;Robert Ndou
    • Anatomy and Cell Biology
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    • v.56 no.4
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    • pp.552-561
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    • 2023
  • The endocrinology of type 2 diabetes (T2D) and its predisposing factors have been studied extensively while its skeletal effects have received negligible research despite this being a global disease. The cellular and molecular association between proximal humeral fractures and T2D has not been fully elucidated. We aimed to study bone cell quantities and immunolabel osteogenic and antiosteogenic cytokines. The study used 12-week-old rats (23 males) consisting of 8 Sprague Dawley (SD) and 15 Zucker Diabetic Sprague Dawley (ZDSD). Weekly mass measurements were taken while fasting blood glucose levels were recorded every 2 weeks with oral glucose tolerance tests conducted once every 4 weeks. Upon termination at the age of 28 weeks, humeri were fixed in 10% buffered formalin, prior to decalcification in ethylenediaminetetraacetic acid. The bone samples were then processed in ascending grades of alcohol using an automatic processor before embedding in paraffin wax. Sections were cut at 5 ㎛ thickness in a series for Haematoxylin and Eosin stain, and immunohistochemistry was performed with the anti-tartrate-resistant acid phosphatase (TRAP), anti-alkaline phosphatase (ALP), anti-bone morphogenetic protein 3 (BMP3), anti-transforming growth factor beta 1 (TGFβ1), anti-aged glycation end product (AGE) antibodies in the sequence. ZDSD rats had more adipocytes, BMP3 and AGEs expression with higher numbers of TRAP positive osteocytes and fewer ALP cells although no differences were found in TGFβ1 immunopositivity. We also found that T2D increases the number of AGEs immuno-positive cells, as well as its extracellular expression, thus providing a conducive environment for the interaction of the osteogenic cytokine and its antagonist to suppress osteoblastogenesis. ZDSD groups had higher adipocyte numbers therefore increased marrow adiposity in T2D.

Serum Levels of Xanthine Oxidase Activities in Cyclohexanone-Treated Rats Pretreated with Carbon Tetrachloride

  • Yoon, Chong-Guk
    • Biomedical Science Letters
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    • v.8 no.1
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    • pp.47-52
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    • 2002
  • To investigate an effect of cyclohexanone (CHO) treatment on the serum levels of xanthine oxidase (XO) in liver damaged animals, the rats were intraperitoneally pretreated with 50% carbon tetrachloride ($CCl_4$) in olive oil (0.1 mL/ 100 g body weight) 14 times every other day. To the $CCl_4$-pretreated rats, CHO (1.56 g/kg body weight) was injected once and then the animals were sacrificed at 4 hours after CHO treatment. The increasing rate of serum and liver XO activities to the control was higher in CHO-treated animals pretreated with $CCl_4$ than the $CCl_4$-pretreated those. Concomitantly CHO injection to the $CCl_4$-pretreated animals showed somewhat higher Vmax and lower Km value in the kinetics of liver XO enzyme. Furthermore, increasing rate of hepatic malonedialdehyde content to the control was also higher in CHO-treated animals pretreated with $CCl_4$ than $CCl_4$-pretreated those. On the other hand, the injection of CHO to the $CCl_4$-pretreated animals showed the more enhanced liver damage on the basis of liver function finding; liver weight per body weight (%), serum levels of alanine aminotransferase activity and hepatic glucose-6-phosphatase activity. In conclusion, injection of CHO to the $CCl_4$-pretreated rats led to more increased activity of serum XO and it may be caused by acceleration of hepatocyte membrane permeability and induction of enzyme protein.

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Oct4 resetting by Aurkb–PP1 cell cycle axis determines the identity of mouse embryonic stem cells

  • Shin, Jihoon;Youn, Hong-Duk
    • BMB Reports
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    • v.49 no.10
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    • pp.527-528
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    • 2016
  • In embryonic stem cells (ESCs), cell cycle regulation is deeply connected to pluripotency. Especially, core transcription factors (CTFs) which are essential to maintaining the pluripotency transcription programs should be reset during M/G1 transition. However, it remains unknown about how CTFs are governed during cell cycle progression. Here, we describe that the regulation of Oct4 by Aurora kinase b (Aurkb)/protein phosphatase 1 (PP1) axis during the cell cycle is important for resetting Oct4 to pluripotency and cell cycle related target genes in determining the identity of ESCs. Aurkb starts to phosphorylate Oct4(S229) at the onset of G2/M phase, inducing the dissociation of Oct4 from chromatin, whereas PP1 binds Oct4 and dephosphorylates Oct4(S229) during M/G1 transition, which resets Oct4-driven transcription for pluripotency and the cell cycle. Furthermore, Aurkb phosphormimetic and PP1 binding-deficient mutations in Oct4 disrupt the pluripotent cell cycle, lead to the loss of pluripotency in ESCs, and decrease the efficiency of somatic cell reprogramming. Based on our findings, we suggest that the cell cycle is directly linked to pluripotency programs in ESCs.