Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:2.7.11.1 (protein kinase)
81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In teleosts, ovarian steroidogenesis is under the control of two gonadotropic hormones, GTH I and GTH II, that are structurally and functionally homologous to FSH and LH. The intracellular mechanisms by which GTH I and GTH II stimulate steroidogenesis in the teleost ovary are not well understood. The purpose of this study was to investigate the involvement of the cAMP/protein kinase A (PKA) and protein kinase C (PKC)/Ca2+ signaling pathways in the steroidogenic actions of GTH I and GTH II in the ovary of the brook trout (Salvelinus fontinalis). The cAMP/PKA pathway mediated the actions of GTH I before germinal vesicle breakdown (preGVBD) and GTH II after GVBD and before ovulation (preOV). Experimental increases in intracellular cAMP concentration mimicked the steroidogenic effects of GTH I and GTH II, and an antagonistic analog of cAMP partially blocked them. In addition, GTH I and GTH II stimulated the production of cAMP in preGVBD and preOV follicles, respectively. Activation of the PKC/Ca2+ pathway by a phorbol ester or a Ca2+ ionophore blocked the GTH I- and GTH II-induced steroid production, whereas inhibition of PKC by specific inhibitors potentiated the effects of GTH I. These results suggest that the cAMP/PKA signaling pathway mediates the stimulatory effects of GTH I and GTH II on steroidogenesis, and they also suggest the additional involvement of the PKC/Ca2+ signaling pathway in modulating the actions of gonadotropins in brook trout ovarian follicles.
...
PMID:Stimulation of brook trout ovarian steroidogenesis by gonadotropins I and II is mediated by the cyclic adenosine 3',5'-monophosphate/protein kinase A pathway. 928 3

Ligand- and second messenger-regulated expression of the gene for steroidogenic acute regulatory protein (StAR) was evaluated in luteinized porcine granulosa cells. For comparison, cytochrome P450 side-chain cleavage (P450scc) was examined. Northern hybridization with homologous cDNA probes demonstrated three StAR mRNA species, of 2.7, 1.6, and 0.8 kilobases (kb), with the smallest variably present, and a single P450scc band at 1.9 kb. FSH elevated both STAR and P450scc messages in a dose-dependent manner over 6 h and continually stimulated both over 24 h (p < 0.001). STAR message induction depended on transcription, as did that of P450scc. Over 6 h, actinomycin D eliminated constitutive StAR message and reduced that of P450scc by two thirds, indicating briefer persistence of StAR. Pretreatment with cycloheximide prevented FSH induction of StAR and P450scc mRNA, implicating intermediate protein synthesis in expression of both genes. Dibutyryl cAMP caused time-dependent increases in StAR and P450 mRNAs over 24 h (p < 0.001), indicating the importance of the protein kinase A (PKA) pathway in their gene expression. Activation of the protein kinase C (PKC) pathway by a phorbol ester eliminated FSH induction of STAR mRNA increases (p < 0.01) while only reducing P450scc induction (p < 0.05). Thus, StAR gene expression, as reflected in mRNA abundance, is regulated by FSH via the PKA pathway and is dependent on transcription and translation. Conversely, the PKC pathway inhibits induction of these important steroid synthetic genes in luteinized granulosa cells.
...
PMID:Follicle-stimulating hormone and intracellular second messengers regulate steroidogenic acute regulatory protein messenger ribonucleic acid in luteinized porcine granulosa cells. 928 5

The development of ovarian follicles and subsequent corpus luteum formation is accompanied by very active angiogenesis. Ovarian granulosa cells produce vascular endothelial growth factor (VEGF), which is a potent endothelial cell mitogen and an angiogenic agent. The complementary DNAs of two other factors structurally related to VEGF, namely VEGF-B and VEGF-C, were recently cloned, but little is known of their regulation in the ovary. We first studied the expression of the messenger RNAs (mRNAs) of the three VEGF isotypes in freshly isolated human granulosa-luteal (GL) cells obtained at oocyte retrieval for in vitro fertilization. The hormonal regulation of these mRNAs was subsequently studied in primary cultures of human GL cells. Analysis of cultured GL cell RNA by reverse transcription-PCR revealed that these cells express the alternatively spliced transcripts representing 121-, 145-, and 165-amino acid VEGF isoforms. Northern blot hybridization analyses indicated that transcripts of 4.5 and 3.7 kilobases for VEGF, and 1.4 and 2.4 kilobases for VEGF-B and VEGF-C, respectively, are expressed in human GL cells. The basal VEGF mRNA levels declined steadily, whereas VEGF-B mRNA levels were rather invariant over a 10-day culture period of GL cells. In contrast, VEGF-C mRNA levels increased toward the end of culture. For studying the hormonal regulation of VEGF isotype mRNAs, GL cells were treated with hCG, recombinant human FSH, PGE2, as well as 8-bromo-cAMP and 12-O-tetradecanoylphorbol 13-acetate, which activate protein kinase A- and protein kinase C-dependent signaling pathways, respectively. All test agents stimulated the expression of VEGF mRNA levels in a concentration-dependent manner. Time-course studies indicated that all treatments induced VEGF mRNA levels as early as incubation for 2 h, and the effect was sustained up to 48 h. VEGF-B mRNA levels were not regulated by any of the test agents. However, we found that hCG and 8-bromo-cAMP decreased VEGF-C mRNA levels with a maximal response observed at 24 and 48 h after cellular treatment. We conclude that the mRNAs of VEGF, VEGF-B, and VEGF-C are expressed in human GL cells and that their mRNA steady state levels are regulated in cultured human GL cells in an isotype-specific manner. The differential regulation of VEGF, VEGF-B, and VEGF-C in human GL cells suggests that distinct VEGF isotypes may play different roles during the vascularization of the human ovarian follicle and corpus luteum.
...
PMID:Differential hormonal regulation of vascular endothelial growth factors VEGF, VEGF-B, and VEGF-C messenger ribonucleic acid levels in cultured human granulosa-luteal cells. 934 2

The aim of this study was to investigate whether the stimulatory effect of growth hormone (GH) on the in vitro maturation and cumulus expansion of bovine oocytes is exerted through the cAMP or the tyrosine kinase pathway. Therefore bovine cumulus-oocyte complexes (COCs) were cultured in Medium 199 without fetal calf serum and gonadotropins, but supplemented with 100 ng/ml bovine GH (bGH; NIH-GH-B18) with or without 10 microM methyl 2,5-dihydroxycinnamate (erbstatin analogue), a specific tyrosine kinase inhibitor; 100 microM 2',3'-dideoxyadenosine (DDA), a specific adenylate cyclase inhibitor; or 10 microM H-89, a specific inhibitor of cAMP-dependent protein kinase A. Epidermal growth factor (EGF; 20 ng/ml) was added as a positive control for tyrosine kinase activation, and FSH (0.05 IU/ml) was added as a positive control for cAMP mediation during in vitro maturation in the absence or presence of the inhibitors. Culture was performed at 39 degrees C in a humidified atmosphere with 5% CO2 in air. To assess the effect on nuclear maturation, the proportion of oocytes in metaphase II stage after 16 h of culture was determined using 4,6-diamino-2-phenylindole staining. To determine the effect on cumulus expansion, the diameter of COCs at the onset and after 24 h of culture was measured. The stimulatory effects of GH on oocyte maturation and cumulus expansion were blocked by DDA and H-89 (p < 0.01). Similarly, FSH-induced cumulus expansion was abolished by DDA and H-89 (p < 0.05), while DDA did not block either EGF-induced oocyte maturation or cumulus expansion. Erbstatin analogue significantly blocked the stimulation of oocyte maturation and cumulus expansion by EGF (p < 0.02) but did not inhibit GH action on the COCs. It is concluded that the stimulatory effect of GH on oocyte maturation and cumulus expansion is mediated by the cAMP signal transduction pathway and not by JAK2 phosphorylation.
...
PMID:Stimulatory effect of growth hormone on in vitro maturation of bovine oocytes is exerted through the cyclic adenosine 3',5'-monophosphate signaling pathway. 940 58

Recently, a family of novel, serine/threonine protein kinases has been identified. One of these transcriptionally inducible, immediate-early genes encodes serum/glucocorticoid inducible-protein kinase, sgk. By in situ hybridization, we show that sgk expression in the rat ovary is selectively localized to granulosa cells. In culture, FSH or forskolin, activators of the protein kinase A (PKA) pathway, rapidly (2 h) and transiently increased sgk mRNA levels in undifferentiated granulosa cells. Sgk mRNA exhibited a biphasic expression pattern, with maximal levels observed at 48 h of FSH/forskolin as granulosa cells differentiate to the preovulatory phenotype. Deletion analyses using sgk promoter-reporter constructs (-4.0 kb to -35 bp) identified a region between -63 and -43 bp that mediated FSH and forskolin-responsive transcription in undifferentiated and differentiated granulosa cells. This G/C-rich region 1) conferred both basal and inducible transcription to the minimal -35 sgk promoter chloramphenicol acetyltransferase reporter construct, 2) specifically bound Sp1 and Sp3 present in granulosa cell extracts, and 3) bound recombinant Sp1. Mutation of 2 bp in this region not only prevented Sp1 and Sp3 binding, but also abolished the PKA-mediated transactivation observed when using the wild type construct. Sp1 and Sp3 DNA-binding activity and protein levels did not change significantly during sgk induction. Collectively, these data indicate that Sp1/Sp3 transactivation of the sgk promoter likely involves regulated, phosphorylation-dependent interaction with other factors. Thus the novel, biphasic induction of sgk that correlates with granulosa cell progression from proliferation to differentiation appears to involve sequential, coordinated actions of FSH, PKA, and transcription factors, including Sp1 and Sp3.
...
PMID:Follicle stimulating hormone-regulated expression of serum/glucocorticoid-inducible kinase in rat ovarian granulosa cells: a functional role for the Sp1 family in promoter activity. 941 98

FSH action on granulosa cells involves the generation of cAMP and subsequent activation of the cAMP-dependent protein kinase (PKA). The PKA holoenzyme is targeted to specific subcellular sites through the interaction of the regulatory subunits with A-kinase anchoring proteins (AKAPs). We previously reported that FSH regulates expression of AKAPs. In this report we examine the relationship between AKAP expression and cell shape. Granulosa cells cultured in the absence of FSH tend to spread and flatten. Cell spreading is accompanied by an increased expression of a 140-kDa AKAP. This spreading/flattening phenotype is independent of the specific extracellular matrix proteins (fibronectin, polylysine, and gelatin) on which cells are plated. Addition of FSH prevents both cell spreading and induction of AKAP 140. Culturing cells on poly (2-hydroxyethyl methacrylate), a surface-coating agent that inhibits cell spreading and adhesion, also inhibits expression of AKAP 140. Addition of phorbol myristate acetate, an agent known to antagonize FSH actions, blocks FSH regulation of both cell shape and AKAP 140 expression. Addition of dexamethasone plus FSH causes a synergistic increase in progesterone levels but has no effect on cell shape or induction of AKAP 140. Dexamethasone produces a dose-dependent increase in AKAP 80 expression, which is blocked by FSH, suggesting cross talk between the glucocorticoid and FSH receptor signaling pathways. These data suggest that expression of AKAP 140 is linked to regulation of cell shape, and that changes in the expression of AKAPs are regulated by several different signaling pathways.
...
PMID:Regulation of expression of A-kinase anchoring proteins in rat granulosa cells. 962 11

This study investigates the possibility that FSH activates the p38 mitogen-activated protein kinase (MAPK) pathway in immature granulosa cells (GC). FSH induced the phosphorylation (activation) of p38 MAPK as evaluated by immunoprecipitation and by phosphorylation-specific immunoblotting. FSH-induced phosphorylation of p38 MAPK was blocked by pretreatment with the protein kinase A (PKA) inhibitor H89 and mimicked by the cAMP generating agonist forskolin, indicating that FSH-induced cAMP production and PKA activation are necessary and sufficient for the activation of p38 MAPK in GC. The small heat shock protein HSP-27 comprises a downstream phosphorylation target for the p38 MAPK pathway. FSH-induced phosphorylation of HSP-27 was blocked by pretreatment with the p38 MAPK inhibitor SB 203580, indicating that p38 MAPK activation is necessary for FSH-induced HSP-27 phosphorylation. FSH-induced GC rounding/aggregation was blocked by pretreatment with SB 203580 indicating that p38 MAPK activation is necessary for FSH-induced GC cell shape change. The results of these experiments show that the p38 MAPK pathway is activated in GC in response to FSH in a cAMP/PKA-dependent manner, and that p38 MAPK activity is required for FSH-induced HSP-27 phosphorylation as well as rounding/aggregation in GC.
...
PMID:Follicle stimulating hormone (FSH) activates the p38 mitogen-activated protein kinase pathway, inducing small heat shock protein phosphorylation and cell rounding in immature rat ovarian granulosa cells. 964 11

Sertoli cells secrete plasminogen activators (PAs) on both sides of the blood-testis barrier, i.e., in the basal and apical compartments of the seminiferous tubules, whereas peritubular cells secrete plasminogen activator inhibitor-1 (PAI-1), a fast-acting and specific PA inhibitor. While it is likely that PAI-1 produced by peritubular cells counteracts the basal secretion of PA, the nature of the PA inhibitor acting in the apical compartment remains to be demonstrated. In the present study, we showed that Sertoli cells recovered from 20-day-old rats and cultured contained a transcript of 3-3.2 kilobases, which hybridized specifically to a PAI-1 cDNA probe (Northern blot). We verified that the observed PAI-1 transcript could not result solely from the peritubular cells (weakly contaminating the Sertoli cell cultures), by comparing PAI-1 mRNA levels of Sertoli and peritubular cells recovered from 20-day-old rats and cultured. We also demonstrated that cultured Sertoli cells secreted a protein that complexed with tissue-type PA (zymography), indicating that it was biologically active. This protein comigrated with purified PAI-1 as a doublet of 46 and 49 kDa (Western blot). The trophic hormone FSH decreased PAI-1 messenger RNA as well as immunoreactive PAI-1 protein (probably via the cAMP protein kinase A pathway), whereas transforming growth factor ss1 and basic fibroblast growth factor (in a nanomolar concentration) increased both of these. These observations support the hypothesis that PAI-1 is expressed by Sertoli cells and is under a complex hormonal (FSH) and paracrine and/or autocrine control exerted at least by basic fibroblast growth factor and transforming growth factor ss1.
...
PMID:Plasminogen activator inhibitor-1 is expressed in cultured rat Sertoli cells. 971 58

Expression of progesterone receptor (PR) mRNA in granulosa cells of ovarian preovulatory follicles is induced by LH (1, 2) and is essential for ovulation (3). Although 17beta-estradiol (E) can induce PR mRNA and activate PR promoter-reporter constructs in other cell types, the effects of E in granulosa cells appear to be indirect. We show herein that E alone does not induce the expression of PR mRNA in preovulatory granulosa cells. Rather, induction of PR mRNA depends on the differentiation of granulosa cells in response to E and a physiological amount of FSH followed by exposure to agonists (elevated levels of LH, FSH, and forskolin) that markedly increase cAMP. Induction of PR mRNA by forskolin is blocked by the A-kinase inhibitor H89 and cycloheximide but not by the E antagonist, ICI 164,384. These results indicate that phosphorylation and synthesis of some regulatory factor(s) other than or in addition to the estrogen receptor (ER) are essential for transactivation of the PR gene. When distal and proximal PR promoter-reporter constructs that are responsive to E in other cell types were transiently transfected into differentiated granulosa cells, forskolin, but not E, induced activity. Likewise, when a vector containing the consensus vitellogenin B1 gene estrogen response element (ERE) was transfected into differentiated granulosa cells, forskolin, but not E, induced activity. Using electrophoretic mobility shift assays, the consensus ERE was shown to bind ERbeta, the predominant subtype present in rat granulosa cells, and ERalpha, the predominant subtype present in luteal cells, whereas the putative ERE-like region (ERE3) of the proximal PR promoter did not bind either ER subtype. Although the identity of the specific factors binding to the ERE3 site remain to be determined, mutation of this region abolished forskolin-induced activity of ERE3-PR-CAT constructs. The GC-rich region of the distal PR promoter bound Sp1 and Sp3 but not C/EBPalpha/beta, indicating that factors binding to ERE3 interact synergistically with Sp1/Sp3 to confer increased responsiveness of the distal promoter to forskolin. Taken together, these results indicate that activation of the A-kinase pathway leads to the phosphorylation of some transcription factor(s) other than or in addition to ER that is (are) critical for the transactivation of the PR gene and that this mechanism is selectively activated in differentiated granulosa cells possessing a preovulatory phenotype.
...
PMID:Hormone induction of progesterone receptor (PR) messenger ribonucleic acid and activation of PR promoter regions in ovarian granulosa cells: evidence for a role of cyclic adenosine 3',5'-monophosphate but not estradiol. 971 46

The Rel/nuclear factor (NF)-kappaB family of transcription factors are important intracellular conveyors of extracellular signals in a number of systems. However, little is known of their roles in the specialized, hormonally regulated environment of the mammalian testis. In this study NF-kappaB p50 and p65 proteins were found to be constitutively present and active in the nucleus of Sertoli cells cultured from rat testis. In vivo, NF-kappaB proteins are present in the nucleus of Sertoli cells during all 14 (I-XIV) cyclical stages of spermatogenesis; however, nuclear NF-kappaB expression was elevated in stage XIV and remained high in stages I-VII. In contrast, NF-kappaB p50 and p65 subunits are transiently expressed in the nuclei of germ cells with peak levels found in pachytene spermatocytes during stages VII-XI and lower levels in stage I-VII spermatids. Tumor necrosis factor-alpha, which is produced by round spermatids in the testis, increased nuclear NF-kappaB binding activity when added to Sertoli cells. Stimulation of Sertoli cells with activators of the cAMP-protein kinase A (PKA) signaling pathway such as forskolin or FSH also increased NF-kappaB DNA binding activity. Consistent with the cellular localization studies, NF-kappaB was found to be activated as high basal levels of NF-kappaB-stimulated reporter gene expression were detected in transient transfection studies of Sertoli cells. Addition of tumor necrosis factor-alpha to Sertoli cells further stimulated kappaB enhancer-mediated transcription. These findings suggest that NF-kappaB proteins are stage specifically localized to Sertoli cell and spermatocyte nuclei and may play a role in the regulation of stage-specific gene expression during the process of spermatogenesis.
...
PMID:Stage-specific nuclear expression of NF-kappaB in mammalian testis. 981 96


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---