The aim of this study was to clone CAP （adenylyl cyclase-associated protein） gene from Gossypium arboreum L. and develop a platform for expressing and purifying CAP protein, which is a base for the construction and ...The aim of this study was to clone CAP （adenylyl cyclase-associated protein） gene from Gossypium arboreum L. and develop a platform for expressing and purifying CAP protein, which is a base for the construction and function researches of CAP. In this work, a CAP homolog from cotton （DPL971） ovule was identified and cloned. And the cDNA sequence consisted of an open reading frame of 1 416 nucleotides encoding a protein of 471 amino acid residues with a calculated molecular weight of 50.6 kDa. To gain insight on the CAP role in cotton fiber development, the cloned CAP cDNA was expressed. A significant higher yield pure protein was obtained with the chromatographic method. Further experiments showed that the purified protein can bind with the actin in vitro indicating that the recombinant cotton CAP is functional. The procedure described here produced high yield pure protein through one chromatographic step, suitable for further structure-function studies.展开更多
Adenylyl cyclases (ACs) are a special group of enzymes that catalyze formation of the second messenger molecule, 3',5'-cyclic adenosine monophosphate (cAMP) from 5'-adenosine triphosphate (ATP). Apparently...Adenylyl cyclases (ACs) are a special group of enzymes that catalyze formation of the second messenger molecule, 3',5'-cyclic adenosine monophosphate (cAMP) from 5'-adenosine triphosphate (ATP). Apparently, even though cAMP is increasingly becoming an important signaling molecule in higher plants, the identification of plant ACs has somewhat remained slow. Here we report the recombinant cloning, partial expression and affinity purification of the truncated version (AtAC<sup>261-388</sup>) of a putative Arabidopsis thaliana protein (AtAC: At3g21465) followed by a demonstration of its inherent enzymatic activity as an AC. Currently, AtAC is not assigned any particular function in A. thaliana but simply annotated as an AC-like protein and, therefore, we targeted it for our study to establish if it is indeed a bona fide AC molecule. From our work, we firstly, show through enzyme immunoassaying and mass spectrometry that the recombinant AtAC<sup>261-388</sup><sub> </sub>can generate cAMP from ATP in vitro in a manganese-dependent manner that is activated by calcium and hydrogen carbonate. Secondly, we reveal through computational analysis that the AC center of AtAC is solvent-exposed, and amenable to the unhindered access of ATP as a substrate for catalysis. Lastly, we show that the recombinant AtAC<sup>261-388</sup> can complement AC-deficiency (cyaA mutation) in SP850 cells when expressed in this mutant Escherichia coli strain.展开更多
A preliminary study on the interaction of G protein (guanine triphosphate binding pro- tein) b1g2 subunits and their coupled components in cell signal transduction was conducted in vitro. The insect cell lines, Sf9 (S...A preliminary study on the interaction of G protein (guanine triphosphate binding pro- tein) b1g2 subunits and their coupled components in cell signal transduction was conducted in vitro. The insect cell lines, Sf9 (Spodoptera frugiperda) and H5 (Trichoplusia ni ) were used to express the recombinant protein Gb1g2. The cell membrane containing Gb1g2 was isolated through affinity chromatography column with Ni-NTA agarose by FPLC method, and the highly purified protein was obtained. The adenylyl cyclase 2 (AC2) activity assay showed that the purified Gb1g2 could signifi-cantly stimulate AC2 activity. The interaction of b1g2 subunits of G protein with the cytoplasmic tail of various mammalian adenylyl cyclases was monitored by BIAcore technology using NTA sensor chip, which relies on the phenomenon of surface plasmon resonance (SPR). The experiments showed the direct binding of Gb1g2 to the cytoplasmic tail C2 domain of AC2. The specific binding domain of AC2 with Gb1g2 was the same as AC2 activity domain which was stimulated by Gb1g2.展开更多
BACKGROUND Major depressive disorder(MDD)is a highly disabling psychiatric syndrome associated with deficits of specific subpopulations of cortical GABAergic interneurons;however,the underlying molecular mechanism rem...BACKGROUND Major depressive disorder(MDD)is a highly disabling psychiatric syndrome associated with deficits of specific subpopulations of cortical GABAergic interneurons;however,the underlying molecular mechanism remains unknown.Type 3 adenylyl cyclase(ADCY3,AC3),which is important for neuronal excitability,has been implicated in MDD in a genome-wide association study in humans.Moreover,a study reported that ablation of AC3 in mice caused similar symptoms as MDD patients.AIM To determine if disruption of the AC3 gene in different subtypes of GABAergic interneurons of mice causes depression-like behaviors.METHODS Using immunohistochemistry,we investigated the expression of AC3 in two major subtypes GABAergic interneurons:Somatostatin-positive(SST+)and parvalbumin-positive(PV+)neurons.Genetic manipulations were used to selectively disrupt AC3 expression in SST+or PV+interneurons.A series of behavior tests including rotarod test,open field test(OFT),elevated plus maze test(EPM),forced swimming test(FST),and tail suspension test(TST)were used to evaluate the motor ability,anxiety-and depression-like behaviors,respectively.RESULTS Our results indicate that approximately 90.41%of SST+and 91.22%of PV+interneurons express AC3.After ablation of AC3 in SST+interneurons,the mice spent comparable time in the center area in OFT,but significantly less time in the open arms and low frequency of entries to the open arms in EPM.Furthermore,these mice showed prolonged immobility in FST and more freezing in TST.However,there were no significant changes in these behaviors after specific disruption of AC3 in PV+interneurons.CONCLUSION This study indicates that ablation of AC3 in SST+interneurons of mice increases anxiety-and depression-like behaviors in mice,supporting the general hypothesis that decreased AC3 activity may play a role in human depression.展开更多
Changes in the functional activity and levels of Gsa and Gia in heart failure have been studied predominantly in the end-stage failing heart.The objective of this study was to determine if levels and function of Gsa a...Changes in the functional activity and levels of Gsa and Gia in heart failure have been studied predominantly in the end-stage failing heart.The objective of this study was to determine if levels and function of Gsa and Gia2 in rat hearts change over time following acute myocar(lial infarction (MI) and if so,whether the changes in G proteins are associated with changes in heart function.As compared with sham-operated controls, Giα2, level of MI rats did not change at day l,increased by 64% at day 3 (P<0.01) and 55% at day 9 (P< 0.05)accompanied by reduced adenylyl cyclase activity,and returned to control by day 21. By contrast,Gsa level did not change at any time. Cardiac function in MI animals was markedly impaired at days 1,3 and 9 as evidenced by substantial elevation in LVEDP and reduction in +and -dp/dtmax,and partially restored at day 21. The increased Gia2level in MI rats at days 3 and 9 correlated positively to LVEDP(P< 0.05), and negatively to +and -dp/dtmax (p < 0. 01).The results show a three phase dynamic pattern in Gia2 level following acute MI:a lag phase, an increased expression phase associated with marked impairment of heart function,and a late phase in which the expression retums to control level accompanied by partially restored cardlac function.The results suggest that ② in G protein-mediated pathways,cardiac myocytes respond to MI Via regulating the gene expression of the inhibitory pathway, and ② up-regulation of Gia2 levels is related to the severity of impairment in cardiac function.展开更多
Our study investigated effects of C-type natriuretic peptide (CNP) on atrial dynamics and hypoxia inducible factor 1 alpha (HIF-1α) activity in perfused beating rat atria, under hypoxic conditions. Hypoxia significan...Our study investigated effects of C-type natriuretic peptide (CNP) on atrial dynamics and hypoxia inducible factor 1 alpha (HIF-1α) activity in perfused beating rat atria, under hypoxic conditions. Hypoxia significantly increased the levels of HIF-1α, concomitant with decreased trial dynamics. CNP (0.1 μmol/L) further decreased atrial dynamics under hypoxia and suppressed hypoxia-induced stimulation of HIF-1α expression. An adenylylcyclase (AC) activator, forskolin (0.1 μmol/L), significantly up-regulated atrial phosphodiesterase subtype 3A (PDE 3A) protein without affecting hypoxia-induced dynamics. In the presence of forskolin, the inhibitory effects of CNP on hypoxia-induced atrial dynamics and HIF-1α levels were significantly attenuated. Forskolin also prevented hypoxia-induced downregulation of PDE3A protein. These findings suggested that CNP inhibited atrial dynamics and HIF-1α activity in the isolated perfused beating rat atria under hypoxic conditions. Furthermore, both effects were modulated by the AC activator forskolin, through activation of CNP-PDE 3A signaling.展开更多
The functional significance of the endometrial hCG/ LH receptors has been related to a rapid release of prostaglandins. However, as compared to gonads and myometrium, in-endometrium mechanisms of transmembrane signall...The functional significance of the endometrial hCG/ LH receptors has been related to a rapid release of prostaglandins. However, as compared to gonads and myometrium, in-endometrium mechanisms of transmembrane signalling of the hCG/LH receptors are probably not conventional and remain unclear. Here we investigated, in vivo, the potential of hCG to interact with, and stimulate the membrane effector enzyme, adenylyl cyclase (AC), in human endometrium. Hormonal and nonhormonal activation of AC was tested in membrane fractions prepared from endometrial biopsies obtained from patients undergoing evaluation cycles for hormone replacement therapy (HRT) and controlled ovarian hyperstimulation (COH). AC activity was determined by the direct conversion of the substrate ATP into cAMP under unstimulated conditions and in the presence of the non-hormonal activators guanyl nucleotide and forskolin. Also AC activity was tested in the presence of hCG under conditions allowing maximal enzyme stimulation. Isoproterenol and prostaglandin E2 (PGE2) were included for comparison. Immunoblot analyses demonstrated the presence of hCG/LH receptors and Gsα protein and other members of the G protein family in the membrane fractions. Endometrial membranes also exhibited high levels of AC activity compared to luteal membranes used as control. Stimulation by GMP-P(NH)P alone was 196 ± 63 (n = 8) (pmol/mg/ min ± SD). Neither hCG nor isoproterenol showed stimulation of endometrial AC (210 ± 65, and 197 ± 53, respectively;n = 66 assays). But PGE2 stimulated the enzyme system significantly (264 ± 63, p < 0.05;n = 66 assays). These data show that membrane fractions from human endometrium express all the AC system components, namely, hCG/LH receptors, Gsα protein and AC;however, hCG does not stimulate the endometrial AC system. Our data indicate that, in great contrast to gonadal receptors, endometrial hCG/ LH receptors are not coupled to the transmembrane AC effector. The well known release of eicosanoids in response to hCG suggests that th展开更多
Plants, just like any other living organism, naturally get attacked by various pathogenic microorganisms such as bacteria, fungi and viruses. However, unlike animals that utilize their specialized circulatory macropha...Plants, just like any other living organism, naturally get attacked by various pathogenic microorganisms such as bacteria, fungi and viruses. However, unlike animals that utilize their specialized circulatory macrophage system to protect themselves, plants instead use a multi-layered complex system termed the plant innate immunity, which recognizes pathogens and transducing downstream defense responses. They have developed a unique type of trans-membrane receptors or R proteins, which extracellularly, are capable of recognizing pathogen-associated molecular patterns (PAMP) such as flagellin and chitin, while intracellularly, they activate their harbored nucleotide cyclases (NCs) such as adenylyl cyclases (ACs), to generate second messenger molecules such as 3’,5’-cyclic adenosine monophosphate (cAMP), which then propagates and magnifies the defense response. To date, only a single R protein from Arabidopsis thaliana (AtLRR) has been shown to possess AC activity as well as having the ability to defend plants against infection by biotrophic and hemi-biotrophic pathogens. Therefore, in order to further broaden information around the functional roles of this protein (AtLRR), we explored it further, using an array of web-based tools or bioinformatics. These included structural analysis, anatomical expression analysis, developmental expression analysis, co-expression analysis, functional enrichment analysis, stimulus-specific expression analysis and promoter analysis. Findings from structural analysis showed that AtLRR is a multi-domain, trans-membrane molecule that is multi-functional, and thus consistent with all known R-proteins. Findings from anatomical and developmental expression analyses showed that AtLRR is mostly expressed in pollen grains and flowers, senescing leaves as well as during the development of seeds, shoots, roots, seedlings, leaves, flowers, and siliques, linking it to the three key plant physiological processes of reproduction, defense and development respectively. Lastly, findings from co-ex展开更多
Summary: To explore the mechanism of interleukin-1beta ( IL-1β) in the onset of seizure and the effect of IL-1β on the expression of adenylyl cyclase (AC) in rats with seizure induced by L-glutamate. Experimental ra...Summary: To explore the mechanism of interleukin-1beta ( IL-1β) in the onset of seizure and the effect of IL-1β on the expression of adenylyl cyclase (AC) in rats with seizure induced by L-glutamate. Experimental rats were first injected with IL-1β and then L-glutamate (a dose under the threshold) was injected into the right lateral ventricle. The rats were sacrificed 4 h after the onset of epileptic activity and examined for changes in behavior, immunohistochemistry and compared with those with seizure induced by L-glutamate alone. It was found that the expression of AC in hippocampal and neocortex of rats with seizure induced by IL-1β and L-glutamate were stronger than that of control group (P<0.05), without significant difference found between the L-glutamate group and IL-1β plus L-glutamate group in the expression of AC, the latent period and the severity of seizure. When IL-ra were given (i.c.v.) first, there was no epileptic activity and the expression of AC did not increase. There were no differences in the expression of AC of rats with IL-1ra and that of control rats. But when 2-methyl-2-(carboxycyclopropyl)glycine (MCCG) was given (i.c.v.) first, the strongest expression of AC, the shortest latent period and the the most serious seizure activities were observed. The results indicated that IL-1β could facilitate the onset of epilepsy induced by L-glutamate through IL-1R, metabotropic glutamate receptors might work with IL-1R and the increased expression of AC might be involved in the process.展开更多
Circulating tumor cells(CTCs)play an important role in tumor metastases,which is positively correlated with an increased risk of death.Actin-binding proteins,including cofilin(CFL1),profilin 1(PFN1),and adenylate cycl...Circulating tumor cells(CTCs)play an important role in tumor metastases,which is positively correlated with an increased risk of death.Actin-binding proteins,including cofilin(CFL1),profilin 1(PFN1),and adenylate cyclase-associated protein 1(CAP1),are thought to be involved in tumor cell motility and metastasis,specifically in head and neck squamous cell carcinoma(HNSCC).However,currently,there are no published studies on CFL1,PFN1,and CAP1 in CTCs and leukocytes in HNSCC patients.We assessed serum levels of CFL1,PFN1,and CAP1 and the number of CTCs and leukocytes containing these proteins in blood from 31 HNSCC patients(T1-4N0-2M0).The analysis used flow cytometry and an enzyme-linked immunosorbent assay kit.We found that CAP1+CTCs and CAP1+leukocyte subpopulations were prevalent in these HNSCC patient samples,while the prevalence rates of CFL1+and PFN1+CTCs were relatively low.Patients with stage T2-4N1-2M0 had CFL1+and PFN1+CTCs with an elevated PFN1 serum level,compared with the T1-3N0M0 group.In summary,the PFN1 serum level and the relative number of PFN1+CD326+CTCs could be valuable prognostic markers for HNSCC metastases.The current study is the first to obtain data regarding the contents of actin-binding proteins(ABPs)in CTCs,and leukocytes in blood from HNSCC patients.This is also the first to assess the relationship between the number of CTCs subgroups and disease characteristics.展开更多
The levels of the second messenger cyclic nucleotides,cAMP and cGMP are carefully regulated in all cells by the activity of a series of adenylyl and guanylyl cyclases and cyclic nucleotide phosphodiesterases(PDEs).Mos...The levels of the second messenger cyclic nucleotides,cAMP and cGMP are carefully regulated in all cells by the activity of a series of adenylyl and guanylyl cyclases and cyclic nucleotide phosphodiesterases(PDEs).Most of the functions of these second messengers are mediated by activation of cyclic nucleotide dependent kinases or other discrete cyclic nucleotide binding proteins.Furthermore,the regulation and function of all of these enzymes are greatly influenced by the cellular and subcellular compartments in which they are localized.In this talk I will discuss several examples of cAMP-regulated cellular function that depend on the simultaneous,coordinated phosphorylation of multiple control points as determined by phosphoproteomic analysis of cells treated with and without selective phosphodiesterase inhibitors.The data strongly suggest that multiple PDEs work in a synergistic manner to coordinate different functional pools of cAMP.These different pools in turn coordinate not one,but many different steps to yield the final control of cellular function.The data imply that we likely therefore will need to consider a number of new and revised ways to think about cAMP regulation of cellular functions and also about drug design.For example,several different PDEs may need to be inhibited in order to produce meaningful pharmacological effects.The data also imply that the much of this cAMP regulation occurs as stochastic processes in different compartments in the cell.展开更多
基金supported by the support of the National Key Technology R&D Program of China(2006BAD13B04)the National Basic Research Program of China (973 Program, 2004CB117301)
文摘The aim of this study was to clone CAP （adenylyl cyclase-associated protein） gene from Gossypium arboreum L. and develop a platform for expressing and purifying CAP protein, which is a base for the construction and function researches of CAP. In this work, a CAP homolog from cotton （DPL971） ovule was identified and cloned. And the cDNA sequence consisted of an open reading frame of 1 416 nucleotides encoding a protein of 471 amino acid residues with a calculated molecular weight of 50.6 kDa. To gain insight on the CAP role in cotton fiber development, the cloned CAP cDNA was expressed. A significant higher yield pure protein was obtained with the chromatographic method. Further experiments showed that the purified protein can bind with the actin in vitro indicating that the recombinant cotton CAP is functional. The procedure described here produced high yield pure protein through one chromatographic step, suitable for further structure-function studies.
文摘Adenylyl cyclases (ACs) are a special group of enzymes that catalyze formation of the second messenger molecule, 3',5'-cyclic adenosine monophosphate (cAMP) from 5'-adenosine triphosphate (ATP). Apparently, even though cAMP is increasingly becoming an important signaling molecule in higher plants, the identification of plant ACs has somewhat remained slow. Here we report the recombinant cloning, partial expression and affinity purification of the truncated version (AtAC<sup>261-388</sup>) of a putative Arabidopsis thaliana protein (AtAC: At3g21465) followed by a demonstration of its inherent enzymatic activity as an AC. Currently, AtAC is not assigned any particular function in A. thaliana but simply annotated as an AC-like protein and, therefore, we targeted it for our study to establish if it is indeed a bona fide AC molecule. From our work, we firstly, show through enzyme immunoassaying and mass spectrometry that the recombinant AtAC<sup>261-388</sup><sub> </sub>can generate cAMP from ATP in vitro in a manganese-dependent manner that is activated by calcium and hydrogen carbonate. Secondly, we reveal through computational analysis that the AC center of AtAC is solvent-exposed, and amenable to the unhindered access of ATP as a substrate for catalysis. Lastly, we show that the recombinant AtAC<sup>261-388</sup> can complement AC-deficiency (cyaA mutation) in SP850 cells when expressed in this mutant Escherichia coli strain.
基金This work was sup-ported by the National Natural Science Foundation of China (Grant No. 30170615) and National Major Basis Study Develop-mental Plan 973 Project (TG2000016208).
文摘A preliminary study on the interaction of G protein (guanine triphosphate binding pro- tein) b1g2 subunits and their coupled components in cell signal transduction was conducted in vitro. The insect cell lines, Sf9 (Spodoptera frugiperda) and H5 (Trichoplusia ni ) were used to express the recombinant protein Gb1g2. The cell membrane containing Gb1g2 was isolated through affinity chromatography column with Ni-NTA agarose by FPLC method, and the highly purified protein was obtained. The adenylyl cyclase 2 (AC2) activity assay showed that the purified Gb1g2 could signifi-cantly stimulate AC2 activity. The interaction of b1g2 subunits of G protein with the cytoplasmic tail of various mammalian adenylyl cyclases was monitored by BIAcore technology using NTA sensor chip, which relies on the phenomenon of surface plasmon resonance (SPR). The experiments showed the direct binding of Gb1g2 to the cytoplasmic tail C2 domain of AC2. The specific binding domain of AC2 with Gb1g2 was the same as AC2 activity domain which was stimulated by Gb1g2.
基金Supported by National Natural Science Foundation of China,No.81771208 and No.81971043。
文摘BACKGROUND Major depressive disorder(MDD)is a highly disabling psychiatric syndrome associated with deficits of specific subpopulations of cortical GABAergic interneurons;however,the underlying molecular mechanism remains unknown.Type 3 adenylyl cyclase(ADCY3,AC3),which is important for neuronal excitability,has been implicated in MDD in a genome-wide association study in humans.Moreover,a study reported that ablation of AC3 in mice caused similar symptoms as MDD patients.AIM To determine if disruption of the AC3 gene in different subtypes of GABAergic interneurons of mice causes depression-like behaviors.METHODS Using immunohistochemistry,we investigated the expression of AC3 in two major subtypes GABAergic interneurons:Somatostatin-positive(SST+)and parvalbumin-positive(PV+)neurons.Genetic manipulations were used to selectively disrupt AC3 expression in SST+or PV+interneurons.A series of behavior tests including rotarod test,open field test(OFT),elevated plus maze test(EPM),forced swimming test(FST),and tail suspension test(TST)were used to evaluate the motor ability,anxiety-and depression-like behaviors,respectively.RESULTS Our results indicate that approximately 90.41%of SST+and 91.22%of PV+interneurons express AC3.After ablation of AC3 in SST+interneurons,the mice spent comparable time in the center area in OFT,but significantly less time in the open arms and low frequency of entries to the open arms in EPM.Furthermore,these mice showed prolonged immobility in FST and more freezing in TST.However,there were no significant changes in these behaviors after specific disruption of AC3 in PV+interneurons.CONCLUSION This study indicates that ablation of AC3 in SST+interneurons of mice increases anxiety-and depression-like behaviors in mice,supporting the general hypothesis that decreased AC3 activity may play a role in human depression.
文摘Changes in the functional activity and levels of Gsa and Gia in heart failure have been studied predominantly in the end-stage failing heart.The objective of this study was to determine if levels and function of Gsa and Gia2 in rat hearts change over time following acute myocar(lial infarction (MI) and if so,whether the changes in G proteins are associated with changes in heart function.As compared with sham-operated controls, Giα2, level of MI rats did not change at day l,increased by 64% at day 3 (P<0.01) and 55% at day 9 (P< 0.05)accompanied by reduced adenylyl cyclase activity,and returned to control by day 21. By contrast,Gsa level did not change at any time. Cardiac function in MI animals was markedly impaired at days 1,3 and 9 as evidenced by substantial elevation in LVEDP and reduction in +and -dp/dtmax,and partially restored at day 21. The increased Gia2level in MI rats at days 3 and 9 correlated positively to LVEDP(P< 0.05), and negatively to +and -dp/dtmax (p < 0. 01).The results show a three phase dynamic pattern in Gia2 level following acute MI:a lag phase, an increased expression phase associated with marked impairment of heart function,and a late phase in which the expression retums to control level accompanied by partially restored cardlac function.The results suggest that ② in G protein-mediated pathways,cardiac myocytes respond to MI Via regulating the gene expression of the inhibitory pathway, and ② up-regulation of Gia2 levels is related to the severity of impairment in cardiac function.
文摘Our study investigated effects of C-type natriuretic peptide (CNP) on atrial dynamics and hypoxia inducible factor 1 alpha (HIF-1α) activity in perfused beating rat atria, under hypoxic conditions. Hypoxia significantly increased the levels of HIF-1α, concomitant with decreased trial dynamics. CNP (0.1 μmol/L) further decreased atrial dynamics under hypoxia and suppressed hypoxia-induced stimulation of HIF-1α expression. An adenylylcyclase (AC) activator, forskolin (0.1 μmol/L), significantly up-regulated atrial phosphodiesterase subtype 3A (PDE 3A) protein without affecting hypoxia-induced dynamics. In the presence of forskolin, the inhibitory effects of CNP on hypoxia-induced atrial dynamics and HIF-1α levels were significantly attenuated. Forskolin also prevented hypoxia-induced downregulation of PDE3A protein. These findings suggested that CNP inhibited atrial dynamics and HIF-1α activity in the isolated perfused beating rat atria under hypoxic conditions. Furthermore, both effects were modulated by the AC activator forskolin, through activation of CNP-PDE 3A signaling.
文摘The functional significance of the endometrial hCG/ LH receptors has been related to a rapid release of prostaglandins. However, as compared to gonads and myometrium, in-endometrium mechanisms of transmembrane signalling of the hCG/LH receptors are probably not conventional and remain unclear. Here we investigated, in vivo, the potential of hCG to interact with, and stimulate the membrane effector enzyme, adenylyl cyclase (AC), in human endometrium. Hormonal and nonhormonal activation of AC was tested in membrane fractions prepared from endometrial biopsies obtained from patients undergoing evaluation cycles for hormone replacement therapy (HRT) and controlled ovarian hyperstimulation (COH). AC activity was determined by the direct conversion of the substrate ATP into cAMP under unstimulated conditions and in the presence of the non-hormonal activators guanyl nucleotide and forskolin. Also AC activity was tested in the presence of hCG under conditions allowing maximal enzyme stimulation. Isoproterenol and prostaglandin E2 (PGE2) were included for comparison. Immunoblot analyses demonstrated the presence of hCG/LH receptors and Gsα protein and other members of the G protein family in the membrane fractions. Endometrial membranes also exhibited high levels of AC activity compared to luteal membranes used as control. Stimulation by GMP-P(NH)P alone was 196 ± 63 (n = 8) (pmol/mg/ min ± SD). Neither hCG nor isoproterenol showed stimulation of endometrial AC (210 ± 65, and 197 ± 53, respectively;n = 66 assays). But PGE2 stimulated the enzyme system significantly (264 ± 63, p < 0.05;n = 66 assays). These data show that membrane fractions from human endometrium express all the AC system components, namely, hCG/LH receptors, Gsα protein and AC;however, hCG does not stimulate the endometrial AC system. Our data indicate that, in great contrast to gonadal receptors, endometrial hCG/ LH receptors are not coupled to the transmembrane AC effector. The well known release of eicosanoids in response to hCG suggests that th
文摘Plants, just like any other living organism, naturally get attacked by various pathogenic microorganisms such as bacteria, fungi and viruses. However, unlike animals that utilize their specialized circulatory macrophage system to protect themselves, plants instead use a multi-layered complex system termed the plant innate immunity, which recognizes pathogens and transducing downstream defense responses. They have developed a unique type of trans-membrane receptors or R proteins, which extracellularly, are capable of recognizing pathogen-associated molecular patterns (PAMP) such as flagellin and chitin, while intracellularly, they activate their harbored nucleotide cyclases (NCs) such as adenylyl cyclases (ACs), to generate second messenger molecules such as 3’,5’-cyclic adenosine monophosphate (cAMP), which then propagates and magnifies the defense response. To date, only a single R protein from Arabidopsis thaliana (AtLRR) has been shown to possess AC activity as well as having the ability to defend plants against infection by biotrophic and hemi-biotrophic pathogens. Therefore, in order to further broaden information around the functional roles of this protein (AtLRR), we explored it further, using an array of web-based tools or bioinformatics. These included structural analysis, anatomical expression analysis, developmental expression analysis, co-expression analysis, functional enrichment analysis, stimulus-specific expression analysis and promoter analysis. Findings from structural analysis showed that AtLRR is a multi-domain, trans-membrane molecule that is multi-functional, and thus consistent with all known R-proteins. Findings from anatomical and developmental expression analyses showed that AtLRR is mostly expressed in pollen grains and flowers, senescing leaves as well as during the development of seeds, shoots, roots, seedlings, leaves, flowers, and siliques, linking it to the three key plant physiological processes of reproduction, defense and development respectively. Lastly, findings from co-ex
文摘Summary: To explore the mechanism of interleukin-1beta ( IL-1β) in the onset of seizure and the effect of IL-1β on the expression of adenylyl cyclase (AC) in rats with seizure induced by L-glutamate. Experimental rats were first injected with IL-1β and then L-glutamate (a dose under the threshold) was injected into the right lateral ventricle. The rats were sacrificed 4 h after the onset of epileptic activity and examined for changes in behavior, immunohistochemistry and compared with those with seizure induced by L-glutamate alone. It was found that the expression of AC in hippocampal and neocortex of rats with seizure induced by IL-1β and L-glutamate were stronger than that of control group (P<0.05), without significant difference found between the L-glutamate group and IL-1β plus L-glutamate group in the expression of AC, the latent period and the severity of seizure. When IL-ra were given (i.c.v.) first, there was no epileptic activity and the expression of AC did not increase. There were no differences in the expression of AC of rats with IL-1ra and that of control rats. But when 2-methyl-2-(carboxycyclopropyl)glycine (MCCG) was given (i.c.v.) first, the strongest expression of AC, the shortest latent period and the the most serious seizure activities were observed. The results indicated that IL-1β could facilitate the onset of epilepsy induced by L-glutamate through IL-1R, metabotropic glutamate receptors might work with IL-1R and the increased expression of AC might be involved in the process.
文摘Circulating tumor cells(CTCs)play an important role in tumor metastases,which is positively correlated with an increased risk of death.Actin-binding proteins,including cofilin(CFL1),profilin 1(PFN1),and adenylate cyclase-associated protein 1(CAP1),are thought to be involved in tumor cell motility and metastasis,specifically in head and neck squamous cell carcinoma(HNSCC).However,currently,there are no published studies on CFL1,PFN1,and CAP1 in CTCs and leukocytes in HNSCC patients.We assessed serum levels of CFL1,PFN1,and CAP1 and the number of CTCs and leukocytes containing these proteins in blood from 31 HNSCC patients(T1-4N0-2M0).The analysis used flow cytometry and an enzyme-linked immunosorbent assay kit.We found that CAP1+CTCs and CAP1+leukocyte subpopulations were prevalent in these HNSCC patient samples,while the prevalence rates of CFL1+and PFN1+CTCs were relatively low.Patients with stage T2-4N1-2M0 had CFL1+and PFN1+CTCs with an elevated PFN1 serum level,compared with the T1-3N0M0 group.In summary,the PFN1 serum level and the relative number of PFN1+CD326+CTCs could be valuable prognostic markers for HNSCC metastases.The current study is the first to obtain data regarding the contents of actin-binding proteins(ABPs)in CTCs,and leukocytes in blood from HNSCC patients.This is also the first to assess the relationship between the number of CTCs subgroups and disease characteristics.
文摘The levels of the second messenger cyclic nucleotides,cAMP and cGMP are carefully regulated in all cells by the activity of a series of adenylyl and guanylyl cyclases and cyclic nucleotide phosphodiesterases(PDEs).Most of the functions of these second messengers are mediated by activation of cyclic nucleotide dependent kinases or other discrete cyclic nucleotide binding proteins.Furthermore,the regulation and function of all of these enzymes are greatly influenced by the cellular and subcellular compartments in which they are localized.In this talk I will discuss several examples of cAMP-regulated cellular function that depend on the simultaneous,coordinated phosphorylation of multiple control points as determined by phosphoproteomic analysis of cells treated with and without selective phosphodiesterase inhibitors.The data strongly suggest that multiple PDEs work in a synergistic manner to coordinate different functional pools of cAMP.These different pools in turn coordinate not one,but many different steps to yield the final control of cellular function.The data imply that we likely therefore will need to consider a number of new and revised ways to think about cAMP regulation of cellular functions and also about drug design.For example,several different PDEs may need to be inhibited in order to produce meaningful pharmacological effects.The data also imply that the much of this cAMP regulation occurs as stochastic processes in different compartments in the cell.
