Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.1 (protein kinase)
 81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The present study was performed to characterize the direct involvement of cAMP-dependent protein kinase (PKA) in the regulation of collagen synthesis by parathyroid hormone (PTH) and PTH-related peptide (PTHrP) in osteoblastic osteosarcoma cells, UMR-106. Sp-cAMPS (10(-4)M), a direct activator of PKA, as well as dibutyryl cAMP (dbcAMP, 10(-4)M) significantly inhibited collagen synthesis. Human (h) PTH-(1-34) (10(-7)M) and hPTHrP (10(-7) M) inhibited collagen synthesis to the same degree. Although Rp-cAMPS, which acted directly as an antagonist in the activation of PKA, did not affect collagen synthesis by itself, it significantly antagonized dbcAMP- and Sp-cAMPS-induced inhibition of collagen synthesis. Moreover, Rp-cAMPS antagonized PTH- and PTHrP-induced inhibition of collagen synthesis to the same degree. The present study first indicated that the activation of PKA was directly linked to the regulation of collagen synthesis by PTH in osteoblast and that PTHrP had the same effect on collagen synthesis presumably through the same mechanism as PTH.
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PMID:The direct involvement of cAMP-dependent protein kinase in the regulation of collagen synthesis by parathyroid hormone (PTH) and PTH-related peptide in osteoblast-like osteosarcoma cells (UMR-106). 131 99

The present study was performed to investigate the regulation of cytosolic pH (pHi) and DNA synthesis by parathyroid hormone(PTH) and PTH-related peptide (PTHrP) in osteoblasts, using osteoblastic osteosarcoma cells, UMR-106 which possessed PTH-responsive dual signal transduction systems (cAMP-dependent protein kinase (PKA) and calcium/protein kinase C [Ca/PKC]) and amiloride-inhibitable Na+/H+ exchange system. Both human (h)PTH-(1-34) and hPTHrP-(1-34) caused a progressive decrease in pHi and the inhibition of [3H]thymidine incorporation (TdR) to the same degree in a dose-dependent manner with a minimal effective dose of 10(-10) M. Dibutyryl cAMP (10(-4) M and Sp-cAMPS (10(-4) M), a direct stimulator of PKA also caused a progressive decrease in pHi, and calcium ionophores (A23187 and ionomycin, 10(-6) M) caused a transient decrease in pHi. Pretreatment with amiloride (0.3 mM) mostly blocked dbcAMP- and Sp-cAMPS-induced decrease in pHi but did not affect calcium ionophore-induced decrease in pHi. In the presence of amiloride, PTH and PTHrP caused a transient decrease in pHi, which was similar to the pattern of calcium ionophore-induced change in pHi. Amiloride did not affect the inhibition of TdR by PTH or PTHrP as well as that by cAMP analogues or calcium ionophores. The present study indicated that PTH and PTHrP caused cytosolic acidification through PKA-inhibited Na+/H+ exchange and increased cytosolic calcium-induced pathway and that the regulation of DNA synthesis by PTH and PTHrP was not via Na+/H+ exchange system.
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PMID:Second messenger signaling in the regulation of cytosolic pH and DNA synthesis by parathyroid hormone (PTH) and PTH-related peptide in osteoblastic osteosarcoma cells: role of Na+/H+ exchange. 132 38

We employed a cyclic AMP-resistant subclone of UMR 106-01 osteoblastic osteosarcoma cells (UMR 4-7) with a regulated, dominant-negative mutation of cyclic AMP-dependent protein kinase (PK-A), to examine the mechanism(s) whereby parathyroid hormone (PTH) regulates growth of these cells. Expression of a transiently transfected CAT reporter gene controlled by the cAMP response element of the rat somatostatin gene ('SST-CAT') was used to monitor PK-A activation in intact cells. Agonist-stimulated SST-CAT expression was specific for agents known to activate adenylate cyclase, required an intact cAMP response element and was specifically blocked following induction of the mutant cAMP-resistant phenotype in UMR 4-7 cells. Inhibition of the proliferation of UMR 106-01 cells by PTH, which is mimicked by forskolin and 8-bromo-cAMP, was blocked completely in mutant cyclic AMP-resistant UMR 4-7 cells. We conclude that control of proliferation in UMR 106-01 cells by PTH involves the cAMP messenger system and requires activation of PK-A.
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PMID:Regulation of gene transcription and proliferation by parathyroid hormone is blocked in mutant osteoblastic cells resistant to cyclic AMP. 135 85

In order to characterize the direct involvement of cAMP in the change of osteoblast proliferation by parathyroid hormone (PTH), we employed the diastereoisomers of adenosine 3',5'-cyclic phosphorothioate, Sp-cAMPS and Rp-cAMPS, which have been recently shown to act directly as agonist and antagonist, respectively in the activation of cAMP-dependent protein kinase (PKA). Dibutyryl cAMP (dbcAMP) and cholera toxin as well as human(h) PTH-(1-34) significantly inhibited [3H]thymidine incorporation (TdR) in osteoblastic osteosarcoma cells, UMR-106. Sp-cAMPS (10(-6)-10(-4) M) inhibited TdR in a dose-dependent manner. Although Rp-cAMPS (10(-6)-10(-4) M) itself did not affect TdR, it significantly blocked dbcAMP-, cholera toxin- and Sp-cAMPS-induced suppression of TdR. Moreover, Rp-cAMPS (10(-6)-10(-4) M) dose-dependently antagonized hPTH-induced suppression of TdR. Present studies first indicated that the activation of PKA is directly linked to the change of osteoblast proliferation by PTH.
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PMID:The activation of cAMP-dependent protein kinase is directly linked to the regulation of osteoblast proliferation (UMR-106) by parathyroid hormone. 164 60

The present study was performed to compare the effect of parathyroid hormone-related protein (PTHrP) on the proliferation of osteoblastic osteosarcoma cells (UMR-106) with that of PTH and characterize the direct involvement of cAMP in the change of osteoblast proliferation by PTHrP. Human(h)PTHrP-(1-34) (10(-11)-10(-7)M) dose-dependently inhibited [3H]thymidine incorporation (TdR) in the same manner as hPTH-(1-34). The simultaneous addition of PTHrP and PTH at a maximal effective dose of 10(-7) M did not cause additive suppressive effect on cell proliferation. Rp-cAMPs, which has been recently shown to act directly as antagonist in the activation of cAMP-dependent protein kinase (PKA), dose-dependently (10(-6)-10(-4)M) antagonized PTHrP-induced suppression of TdR in the same manner as PTH. Present study indicated that PTHrP has the same effect on osteoblast proliferation as PTH and that the activation of PKA is directly linked to the change of osteoblast proliferation by PTHrP.
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PMID:The activation of cAMP-dependent protein kinase is directly linked to the inhibition of osteoblast proliferation (UMR-106) by parathyroid hormone-related protein. 188 95

Individual prostanoids have distinct potencies in activating intracellular signaling pathways and regulating gene expression in osteoblastic cells. The E-series prostaglandins (PGs) are known to stimulate matrix metalloproteinase-1 (MMP-1) synthesis and secretion in certain rodent and human osteoblastic cells, yet the intracellular events involved remain unclear. To further characterize this response and its signal transduction pathway(s), we examined prostanoid-induced expression of the MMP-1 gene in the rat osteoblastic osteosarcoma cell line UMR 106-01. Northern blot analysis demonstrated that prostaglandin E2 (PGE2) and PGE1 were very potent stimulators (40-fold) of MMP-1 transcript abundance, PGF2 alpha and prostacyclin were weak stimulators (4-fold), and thromboxane-B2 had no effect. The marked increase in MMP-1 transcript abundance after PGE2 treatment was first detected at 2 h, became maximal at 4 h, and persisted beyond 24 h. This response was dose dependent and elicited maximal and half-maximal effects with concentrations of 10(-6) and 0.6 x 10(-7) M, respectively. Cycloheximide, a protein synthesis inhibitor, completely blocked this effect of PGE2, suggesting that the expression of other genes is required. Nuclear run-on experiments demonstrated that PGE2 rapidly activates MMP-1 gene transcription, with a maximal increase at 2-4 h. The second messenger analog, 8-bromo-cAMP, mimicked the effects of PGE2 by stimulating a dose-dependent increase in MMP-1 messenger RNA (mRNA) levels, with a maximal effect quantitatively similar to that observed with PGE2. Thus, in UMR 106-01 cells, different prostanoids have distinct potencies in stimulating MMP-1 mRNA abundance. Our data suggest that PGE2 stimulation of MMP-1 synthesis is due to activation of MMP-1 gene transcription and a subsequent marked increase in MMP-1 mRNA abundance. This effect is dependent on de novo protein synthesis and is mimicked by protein kinase-A activation.
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PMID:Prostanoid-induced expression of matrix metalloproteinase-1 messenger ribonucleic acid in rat osteosarcoma cells. 792 6

The present study was performed to clarify second messenger signaling in parathyroid hormone (PTH)-induced c-fos gene expression, to characterize the participation of the c-fos gene in the regulation of osteoblast proliferation and function as well as osteoclast-like cell formation by PTH and to compare these effects of PTH with those of PTH-related peptide (PTHrP). Both human (h) PTH-(1-34) and hPTHrP-(1-34) at 10(-8) M induced a transient c-fos gene expression to a similar degree in osteoblastic osteosarcoma cells, UMR-106. N6,O2'-dibutyryl adenosine 3',5'-cyclic monophosphate (dbcAMP) as well as Sp-diastereoisomer of adenosine cyclic 3',5'-phosphorothioate (Sp-cAMPS), an activator of cAMP-dependent protein kinase (PKA), induced a weak c-fos gene expression. Although Rp-diastereoisomer of adenosine cyclic 3',5'-phosphorothioate (Rp-cAMPS), an inhibitor of PKA, almost completely antagonized dbCAMP- and Sp-cAMPS-induced expression of c-fos gene, it did not cause an obvious inhibition of PTH- or PTHrP-induced expression. Phorbol 12-myristate 13-acetate (PMA), an activator of protein kinase C (PKC), induced an intense expression of the c-fos gene, while 4 alpha-phorbol 12,13-didecanoate (4 alpha PDD), incapable of activating PKC, and calcium ionophores (A23187 and ionomycin) did not. Protein kinase C inhibitor (H-7, 50 microM) completely blocked the expression of the c-fos gene by PTH as well as by PTHrP). Antisense oligodeoxynucleotides (as-ODN) complementary to c-fos mRNA, which have been shown to inhibit its mRNA translation, at 1 microM significantly antagonized PTH- and PTHrP-induced inhibition of [3H] thymidine incorporation and stimulation of osteoclast-like cell formation in the presence of osteoblasts, but not an increase in alkaline phosphatase activity, compared to control oligodeoxynucleotides with same nucleotides as as-ODN but with a random sequence. The present study indicates the involvement of PKC system in c-fos gene expression by PTH as well as PTHrP and also indicates the involvement of the c-fos gene in the regulation of bone cell physiology by PTH and PTHrP.
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PMID:Second messenger signaling of c-fos gene induction by parathyroid hormone (PTH) and PTH-related peptide in osteoblastic osteosarcoma cells: its role in osteoblast proliferation and osteoclast-like cell formation. 796 20

Our recent study demonstrated the direct involvement of cAMP-dependent protein kinase (PKA) in the regulation of DNA synthesis by PTH-related peptide (PTHrP) in osteoblastic osteosarcoma cells, UMR-106. Since PTHrP has been reported to possess dual signal transduction systems [PKA and calcium/protein kinase C (Ca/PKC]), present study was performed to characterize the involvement of Ca/PKC signal transduction system in the regulation of DNA synthesis by PTHrP in these cells. Human PTHrP-(1-34) (10(-7) M) caused a rapid increase in intracellular Ca ([Ca2+]i), followed by return to the basal level within 1 min. Pretreatment with 10(-4) M TMB-8 or 10(-5) M dantrolene, inhibitors of calcium release from intracellular calcium store, significantly blocked the PTHrP-induced increase in [Ca2+]i, but did not affect the PTHrP-induced inhibition of DNA synthesis. Pretreatment with 50 uM H-7 or 1 nM staurosporine, inhibitors of PKC, significantly blocked the PTHrP (10(-9) to 10(-7) M)-induced inhibition of DNA synthesis. Pretreatment with 10(-6) M phorbol 12-myristate 13-acetate, which downregulated PKC, significantly blocked the inhibition of DNA synthesis by PTHrP. Present study indicates that in addition to PKA activation, PKC activation is coupled to the regulation of DNA synthesis by PTHrP in osteoblasts.
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PMID:Role of calcium/protein kinase C in the regulation of DNA synthesis by parathyroid hormone-related peptide in osteoblastic osteosarcoma cells. 811 63

The present study was performed to characterize the participation of parathyroid hormone (PTH)- and PTH-related peptide (PTHrP)-responsive dual signal transduction systems [cAMP-dependent protein kinase (PKA) and Calcium/protein kinase C (Ca/PKC)] in the regulation of alkaline phosphatase (ALP) activity in osteoblastic osteosarcoma cells (UMR-106). Both human (h) PTH-(1-34) and hPTHrP-(1-34) at 10(-8) M stimulated ALP activity to the similar degree. Dibutyryl, cAMP (dbcAMP) (10(-5), 10(-4) M) and Sp-diastereoisomer of adenosine cyclic 3',5'-phosphorothioate (Sp-cAMPS), a direct stimulator of PKA (10(-4) M) also stimulated its activity. Phorbol 12-myristate 13-acetate (PMA), an activator of PKC, (10(-7), 10(-6) M) did not affect its activity, while calcium ionophores, A23187 and ionomycin (10(-7), 10(-6) M) inhibited it. Although Rp-diastereoisomer of adenosine cyclic 3',5'-phosphorothioate (Rp-cAMPS), a direct inhibitor of PKA, (10(-4) M) did not affect ALP activity by itself, it significantly antagonized not only Sp-cAMPS-induced increase in ALP activity, but also PTH- and PTHrP-induced one. The present study first indicated that the activation of PKA was directly involved and acted as a main pathway in the regulation of ALP activity by PTH and PTHrP in osteoblasts.
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PMID:Direct involvement of cAMP-dependent protein kinase in the regulation of alkaline phosphatase activity by parathyroid hormone (PTH) and PTH-related peptide in osteoblastic UMR-106 cells. 812 23

Rat tissue inhibitor of metalloproteinases-2 (TIMP-2) was cloned from a UMR 106-01 rat osteoblastic osteosarcoma cDNA library. The 969-bp full-length clone demonstrates 98 and 86% sequence identity to human TIMP-2 at the amino acid and nucleic acid levels, respectively. Parathyroid hormone (PTH), at 10(-8) M, stimulates an approximately twofold increase in both the 4.2- and 1.0-kb transcripts over basal levels in UMR cells after 24 h of exposure. The PTH stimulation of TIMP-2 transcripts was not affected by the inhibitor of protein synthesis, cycloheximide (10(-5) M), suggesting a primary effect of the hormone. This is in contradistinction to regulation of interstitial collagenase (matrix metalloproteinase-1) by PTH in these same cells. Nuclear run-on assays demonstrate that PTH causes an increase in TIMP-2 transcription that parallels the increase in message levels. Parathyroid hormone, in its stimulation of TIMP-2 mRNA, appears to act through a signal transduction pathway involving protein kinase A (PKA) since the increase in TIMP-2 mRNA is reproduced by treatment with the cAMP analogue, 8-bromo-cAMP (5 x 10(-3) M). The protein kinase C and calcium pathways do not appear to be involved due to the lack of effect of phorbol 12-myristate 13-acetate (2.6 x 10(-6) M) and the calcium ionophore, ionomycin (10(-7) M), on TIMP-2 transcript abundance. In this respect, regulation of TIMP-2 and collagenase in osteoblastic cells by PTH are similar. However, we conclude that since stimulation of TIMP-2 transcription is a primary event, the PKA pathway must be responsible for a direct increase in transcription of this gene.
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PMID:Cloning and regulation of rat tissue inhibitor of metalloproteinases-2 in osteoblastic cells. 820 93


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