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1.
《Biology of the cell / under the auspices of the European Cell Biology Organization》1995,83(2-3):201-210
The intracellular localizations of phosphatidylinositol 4,5-bisphosphate (PIP2) and of its hydrolyzing enzyme phospholipase C (PLC; in this case the β1 isoform) have been evaluated by electron microscope immunocytochemistry in cells exposed to mitogenic or differentiating agents. These cells have been previously demonstrated to present a signal transduction system based on the polyphosphoinositide hydrolysis localized at the nuclear level, which can be specifically modulated by agonists. The results demonstrate that in Swiss 3T3 mouse fibroblasts mitogenically stimulated by insulin-like growth factor I (IGF-I), a rapid and transient decrease of the PIP2 detectable by immunogold labeling occurs at the nuclear interior. This effect appears due to the activation of the PLC β1 isozyme already present in the nucleus, since no significant variations of the enzyme amount and distribution can be detected by immunolabeling. However, after 30 min of exposure to IGF-I, when the PLC β1 activity is returned to basal level, a slight but significant increase of the enzyme amount is detected both in the nucleus and in the cytoplasm. On the other hand, an increased accumulation of PIP2 in the nucleus, accompanied by a decrease of the intranuclear amount of PLC β1 isozyme, have been observed in mouse erythroleukemia Friend cells, induced to erythroid differentiation by dimethylsulfoxide (DMSO). These results indicate that quantitative immunocytochemistry represents an increment in the available methodologies to investigate the complex regulation of nuclear PI-signalling. 相似文献
2.
H. Kobayashi Hiroko Oyamada Naoko Iwadate Hiromi Suzuki Hideko Mitobe Kaori Takahashi Nobuyuki Shibata Shigeo Suzuki Yoshio Okawa 《Archives of microbiology》1998,169(3):188-194
A mannan of Candida glabrata IFO 0622 digested by Arthrobacter exo-α-mannosidase and a β-1,2-linked mannobiose obtained from the parent mannan by acid treatment was analyzed using 13C nuclear magnetic resonance spectroscopy. The results show that the β-1,2-linked mannobiosyl residue is esterified to a phosphate
group through position C-1 in the α-configuration, Manβ1– 2Manα1–HPO3–. The results of immunochemical assays of these mannans using the commercial antigenic factor sera of the genus Candida (Candida Check, Iatron) indicate that the main recognition site of serum no. 6 in this kit is the mannotetraosyl side-chain
Manβ1–2Manα1– 2Manα1–2Man in C. glabrata mannan and also suggest that the phosphate-containing unit (such as Manβ1– 2Manα1–HPO3– in this mannan) behaves as one of the antigenic determinants of serum no. 6, but not of serum no. 5. Therefore, the present
and previous findings indicate that serum no. 5 recognizes relatively longer β-1,2-linked oligomannosyl side-chains, Manβ1–[2Manβ1–]n 2Man (n = 1–6), attached to the phosphate groups previously observed in the cell wall mannans of Candida albicans, Candida stellatoidea, and Candida tropicalis.
Received: 18 March 1997 / Accepted: 16 September 1997 相似文献
3.
In this study, we examined changes in the biochemical and inotropic events of the α1-adrenoceptor signaling pathway in hypothyroid rat hearts. Hypothyroidism was induced by treating experimental animals with
0.05% 6-n-propyl-2-thiouracil (PTU) in drinking water for 7 weeks. A significant decrease of β- and an increase in α1-adrenoceptor density as well as an increase in the basal activity of the phosphoinositide (4,5) bisphosphate hydrolyzing
phospholipase C was observed in sarcolemmal membranes purified from hypothyroid hearts as compared to age-matched euthyroid
controls. Following stimulation with 10 μM phenylephrine (in the presence of 10 μM atenolol), the increase of contractile
parameters over baseline values was significantly higher in hypo- than euthyroid hearts, while the opposite occurred under
β-stimulation with 0.1 μM isoproterenol. Interestingly, the increase in phenylephrine-mediated positive inotropy was accompanied
by a significant increase in the sarcolemmal phospholipase C activity and in the inositol 1,4,5-trisphosphate content in hypothyroid
as compared to euthyroid controls. Our results suggest that cardiac α1-adrenoceptor and its associated phosphoinositide signaling pathway may act as a reserve for catecholamine inotropic response
in hypothyroidism, where the β-adrenoceptors are compromised.
Deceased 相似文献
4.
β-1,4-galactosyltransferase I (β-1,4-GalT I) plays an important role in the synthesis of the backbone structure of adhesion molecules involved in leukocyte–endothelial
cell interaction. The expression of β-1,4-GalT I mRNA increased in primary human endothelial cells after exposure to tumor necrosis factor-α (TNF-α). In the central nervous system (CNS), astrocytes play a pivotal role in immunity as immunocompetent cells by secreting
cytokines and inflammatory mediators, there are two types of astrocytes. Type-1 astrocytes can secrete TNF-α when stimulated
with Lipopolysaccharide (LPS), while the responses of type-2 astrocytes during inflammation are unknown. So we examined the
expression change of β-1,4-GalT I mRNA in type-2 astrocytes after exposure to TNF-α and LPS. Real-time PCR showed that TNF-α or LPS affected β-1,4-GalT I mRNA expression in a time- and dose-dependent manner. RT-PCR analysis revealed that TNFR1 and TNFR2 were present
in normal untreated type-2 astrocytes, and that TNF-α, TNFR1 and TNFR2 increased in type-2 astrocytes after exposure to TNF-α or LPS. Immunocytochemistry showed that TNFR1 was
expressed in the cytoplasm, nucleus and processes of normal untreated type-2 astrocytes, and distributed mainly in the cytoplasm
and processes after exposure to LPS. TNFR2 was mainly expressed in the nucleus of normal untreated type-2 astrocytes, and
distributed mainly in the processes of type-2 astrocytes after exposure to LPS. Both anti-TNFR1 and anti-TNFR2 antibodies
suppressed β-1,4-GalT I mRNA expression induced by TNF-α or LPS. From these results, we conclude that TNF-α signaling via both TNFR1 and TNFR2 translocated from nucleus to cytoplasm or processes is sufficient to induce β-1,4-GalT I mRNA. In addition, we observed that not only exogenous TNF-α but also TNF-α produced by type-2 astrocytes affected β-1,4-GalT I mRNA production in type-2 astrocytes. These results suggest that an autocrine loop involving TNF-α contributes
to the production of β-1,4-GalT I mRNA in response to inflammation.
Chunlin Xia is the co-first author. 相似文献
5.
P2X1 receptors, the major subtype of P2X receptors in the vascular smooth muscle, are essential for α,β-methylene adenosine 5′-triphosphate
(α,β-MeATP)-induced vasoconstriction. However, relative physiological significance of P2X1 receptor-regulated vasoconstriction in the different types of arteries in the rat is not clear as compared with α1-adrenoceptor-regulated vasoconstriction. In the present study, we found that vasoconstrictive responses to noncumulative
administration of α,β-MeATP in the rat isolated mesenteric arteries were significantly smaller than those to single concentration
administration of α,β-MeATP. Therefore, we firstly reported the characteristic of α,β-MeATP-regulated vasoconstrictions in
rat tail, internal carotid, pulmonary, mesenteric arteries, and aorta using single concentration administration of α,β-MeATP.
The rank order of maximal vasoconstrictions for α,β-MeATP (E
max·α,β-MeATP) was the same as that of maximal vasoconstrictions for noradrenaline (E
max·NA) in the internal carotid, pulmonary, mesenteric arteries, and aorta. Moreover, the value of (E
max·α,β-MeATP/E
max·KCl)/(E
max·NA/E
max·KCl) was 0.4 in each of the four arteries, but it was 0.8 in the tail artery. In conclusion, P2X1 receptor-mediated vasoconstrictions are equally important in rat internal carotid, pulmonary, mesenteric arteries, and aorta,
but much greater in the tail artery, suggesting its special role in physiological function. 相似文献
6.
The α1 subunit coding for the human brain type E calcium channel (Schneider et al., 1994) was expressed in Xenopus oocytes in the absence, and in combination with auxiliary α2δ and β subunits. α1E channels directed with the expression of Ba2+ whole-cell currents that completely inactivated after a 2-sec membrane pulse. Coexpression of α1E with α2bδ shifted the peak current by +10 mV but had no significant effect on whole-cell current inactivation. Coexpression of α1E with β2a shifted the peak current relationship by −10 mV, and strongly reduced Ba2+ current inactivation. This slower rate of inactivation explains that a sizable fraction (40 ± 10%, n= 8) of the Ba2+ current failed to inactivate completely after a 5-sec prepulse. Coinjection with both the cardiac/brain β2a and the neuronal α2bδ subunits increased by ≈10-fold whole-cell Ba2+ currents although coinjection with either β2a or α2bδ alone failed to significantly increase α1E peak currents. Coexpression with β2a and α2bδ yielded Ba2+ currents with inactivation kinetics similar to the β2a induced currents, indicating that the neuronal α2bδ subunit has little effect on α1E inactivation kinetics. The subunit specificity of the changes in current properties were analyzed for all four β subunit
genes. The slower inactivation was unique to α1E/β2a currents. Coexpression with β1a, β1b, β3, and β4, yielded faster-inactivating Ba2+ currents than currents recorded from the α1E subunit alone. Furthermore, α1E/α2bδ/β1a; α1E/α2bδ/β1b; α1E/α2bδ/β3; α1E/α2bδ/β4 channels elicited whole-cell currents with steady-state inactivation curves shifted in the hyperpolarized direction. The
β subunit-induced changes in the properties of α1E channel were comparable to modulation effects reported for α1C and α1A channels with β3≈β1b > β1a≈β4≫β2a inducing fastest to slowest rate of whole-cell inactivation.
Received: 27 March 1997/Revised: 10 July 1997 相似文献
7.
Masłyk M Kochanowicz E Zieliński R Kubiński K Hellman U Szyszka R 《Molecular and cellular biochemistry》2008,312(1-2):61-69
Since Svf1 is phosphoprotein, we investigated whether it was a substrate for protein kinase CK2. According to the amino acid
sequence Svf1 harbours 20 putative CK2 phosphorylation sites. Here, we have reported cloning, overexpression, purification
and characterization of yeast Svf1 as a substrate for three forms of yeast CK2. Svf1 serves as a substrate for both the recombinant
CK2α (K
m 0.35 μM) and CK2α′ (K
m 0.18 μM) as well as CK2 holoenzyme (K
m 1.1 μM). Different K
m values argue that CK2β(β′) subunit has an inhibitory effect on the activity of both CK2α and CK2α′ towards surviving factor
Svf1. Reconstitution of α′2ββ′ isoform of CK2 holoenzyme shows that β/β′ subunits have regulatory effect depending on the kind of CK2 catalytic subunit.
This effect was not observed in the case of α2ββ′ isoform, which may be due to interaction between Svf1 and regulatory CK2β subunit (shown by co-immunoprecipitation experiments).
Interactions between CK2 subunits and Svf1 protein may have influence on ATP as well as ATP-competitive inhibitors (TBBt and
TBBz) binding. CK2 phosphorylates up to six serine residues in highly acidic peptide K199EVIPESDEEESSADEDDNEDEDEESGDSEEESGSEEESDSEEVEITYED248 of the Svf1 protein in vitro. Presented data may help to elucidate the role of protein kinase CK2 and Svf1 in the regulation
of cell survival pathways. 相似文献
8.
Kim Y Lucas CA Zhong WW Hoh JF 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2007,177(6):701-705
Ventricular myosin in eutherian mammals undergoes a perinatal change in response to a sharp rise in thyroid hormone levels
during development. In this investigation, changes in ventricular myosin heavy chains (MyHCs) of the tammar wallaby (Macropus eugenii) from early pouch life to adulthood were analysed using native gel electrophoresis, SDS-PAGE and western blotting. Adult
wallaby ventricle showed three myosin isoenzymes, V1, V2 and V3; western blots using specific anti-α-MyHC and anti-β-MyHC antibodies showed their MyHC compositions to be αα, αβ and ββ,
respectively. Ventricular muscle in early pouch joeys expressed predominantly β-MyHC. Up to 200 days, the time of initial
pouch exit, α-MyHC content was around 5%. Thereafter, there was a sharp increase of α-MyHC expression to 35% by 242 days of
age, eventually falling back to 23% in the adult. These changes correlate with known surges in plasma levels of thyroid hormones
around pouch exit. The results suggest that ventricular myosins in a marsupial mammal also undergo a developmental change,
and that marsupial ventricular myosins are thyroid responsive as in eutherians. The increased α-MyHC expression empowers the
heart to meet the enhanced cardiovascular demands of out-of-pouch activity and the thermogenic action of thyroid hormones. 相似文献
9.
B. Cukrowska I. Rosiak E. Klewicka I. Motyl M. Schwarzer Z. Libudzisz H. Kozakova 《Folia microbiologica》2010,55(3):277-280
Heat-inactivated Lactobacillus casei LOCK 0900, L. casei LOCK 0908 and Lactobacillus paracasei LOCK 0919 strains, applied to blood cell cultures obtained from children with atopic dermatitis induced production of anti-allergic
TH1 cytokines (interleukin-12, interleukin-18, interferon-γ, tumor necrosis factor-α) and regulatory transforming growth factor-β1), but did not stimulate pro-allergic interleukin-5. The lactobacilli-mixture remarkably enhanced the TH1 response compared to single strains. This synergistic effect was not observed for transforming growth factor-β1. In contrast, the amount of interleukin-10 was found to be considerably lower when cells were stimulated with lactobacilli-mixture
compared to single strains. The mixture of Lactobacillus strains represents a probiotic bacterial preparation modulating in vitro cytokine profile of allergic children towards anti-allergic TH1 response. 相似文献
10.
Two novel HSQC-IPAP approaches are proposed to achieve α/β spin-state editing simultaneously for 13C and 15N in a single NMR experiment. The pulse schemes are based on a time-shared (TS) 2D 1H,13C/1H,15N-HSQC correlation experiment that combines concatenated echo elements for simultaneous J(CH) and J(NH) coupling constants
evolution, TS evolution of 13C and 15N chemical shifts in the indirect dimension and heteronuclear α/β-spin-state selection by means of the IPAP principle. Heteronuclear
α/β-editing for all CH
n
(n = 1–3) and NH
n
(1–2) multiplicities can be achieved in the detected F2 dimension of a single TS-HSQC-F2-IPAP experiment. On the other hand,
an alternative TS-HSQC-F1-IPAP experiment is also proposed to achieve α/β-editing in the indirect F1 dimension. Experimental
and simulated data is provided to evaluate these principles in terms of sensitivity and performance simultaneously on backbone
and side-chain CH, CH2, CH3, NH, and NH2 spin systems in uniformly 13C/15N-labeled proteins and in small natural-abundance peptides. 相似文献