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1.
Proinsulin C-peptide and its analogues induce intracellular Ca2+ increases in human renal tubular cells 总被引:3,自引:0,他引:3
Shafqat J Juntti-Berggren L Zhong Z Ekberg K Köhler M Berggren PO Johansson J Wahren J Jörnvall H 《Cellular and molecular life sciences : CMLS》2002,59(7):1185-1189
Based on the findings that proinsulin C-peptide binds specifically to cell membranes, we investigated the effects of C-peptide
and related molecules on the intracellular Ca2+ concentration ([Ca2+]i) in human renal tubular cells using the indicator fura-2/AM. The results show that human C-peptide and its C-terminal pentapeptide
(positions 27–31, EGSLQ), but not the des (27–31) C-peptide or randomly scrambled C-peptide, elicit a transient increase in
[Ca2+]i. Rat C-peptide and rat C-terminal pentapeptide also induce a [Ca2+]i response in human tubular cells, while a human pentapeptide analogue with Ala at position 1 gives no [Ca2+]i response, and those with Ala at positions 2–5 induce responses with different amplitudes. These results define a species
cross-reactivity for C-peptide and demonstrate the importance of Glu at position 1 of the pentapeptide. Preincubation of cells
with pertussis toxin abolishes the effect on [Ca2+]i by both C-peptide and the pentapeptide. These results are compatible with previous data on C-peptide binding to cells and
activation of Na+,K+ATPase. Combined, all data show that C-peptide is a bioactive peptide and suggest that it elicits changes in [Ca2+]i via G-protein-coupled pathways, giving downstream enzyme effects.
Received 13 May 2002; accepted 16 May 2002 相似文献
2.
Haijie Yu Zheng Zhang Annette Lis Reinhold Penner Andrea Fleig 《Cellular and molecular life sciences : CMLS》2013,70(15):2757-2771
Transient receptor potential melastatin 7 (TRPM7) is a divalent-selective cation channel fused to an atypical α-kinase. TRPM7 is a key regulator of cell growth and proliferation, processes accompanied by mandatory cell volume changes. Osmolarity-induced cell volume alterations regulate TRPM7 through molecular crowding of solutes that affect channel activity, including magnesium (Mg2+), Mg-nucleotides and a further unidentified factor. Here, we assess whether chloride and related halides can act as negative feedback regulators of TRPM7. We find that chloride and bromide inhibit heterologously expressed TRPM7 in synergy with intracellular Mg2+ ([Mg2+]i) and this is facilitated through the ATP-binding site of the channel’s kinase domain. The synergistic block of TRPM7 by chloride and Mg2+ is not reversed during divalent-free or acidic conditions, indicating a change in protein conformation that leads to channel inactivation. Iodide has the strongest inhibitory effect on TRPM7 at physiological [Mg2+]i. Iodide also inhibits endogenous TRPM7-like currents as assessed in MCF-7 breast cancer cells, where upregulation of SLC5A5 sodium-iodide symporter enhances iodide uptake and inhibits cell proliferation. These results indicate that chloride could be an important factor in modulating TRPM7 during osmotic stress and implicate TRPM7 as a possible molecular mechanism contributing to the anti-proliferative characteristics of intracellular iodide accumulation in cancer cells. 相似文献
3.
Calcium signaling in plants 总被引:9,自引:0,他引:9
Changes in the cytosolic concentration of calcium ions ([Ca2+]i) play a key second messenger role in signal transduction. These changes are visualized by making use of either Ca2+-sensitive fluorescent dyes or the Ca2+-sensitive photoprotein, aequorin. Here we describe the advances made over the last 10 years or so, which have conclusively
demonstrated a second messenger role for [Ca2+]i in a few model plant systems. Characteristic changes in [Ca2+]i have been seen to precede the responses of plant cells and whole plants to physiological stimuli. This has had a major impact
on our understanding of cell signaling in plants. The next challenge will be to establish how the Ca2+ signals are encrypted and decoded in order to provide specificity, and we discuss the current understanding of how this may
be achieved. 相似文献
4.
D. Parolini M. Meregalli M. Belicchi P. Razini R. Lopa B. Del Carlo A. Farini S. Maciotta N. Bresolin L. Porretti M. Pellegrino Y. Torrente 《Cellular and molecular life sciences : CMLS》2009,66(4):697-710
Among the heterogeneous population of circulating hematopoietic and endothelial progenitors, we identified a subpopulation
of CD133+ cells displaying myogenic properties. Unexpectedly, we observed the expression of the B-cell marker CD20 in blood-derived
CD133+ stem cells. The CD20 antigen plays a role in the modulation of intracellular calcium homeostasis through signaling pathways
activation. Several observations suggest that an increase in intracellular calcium concentration ([Ca2+]i) could be involved in the etiology of the Duchenne muscular dystrophy (DMD). Here, we show that a CD20-related signaling
pathway able to induce an increase in [Ca2+]i is differently activated after brain derived neurotrophic factor (BDNF) stimulation of normal and dystrophic blood-derived
CD133+ stem cells, supporting the assumption of a “CD20-related calcium impairment-affecting dystrophic cells. Presented findings
represent the starting point toward the expansion of knowledge on pathways involved in the pathology of DMD and in the behavior
of dystrophic blood-derived CD133+ stem cells.
Received 15 October 2008; received after revision 27 November 2008; accepted 05 December 2008 相似文献
5.
The effect of a phorbol ester upon the cholinergic regulation of potassium permeability in the rat submandibular gland 总被引:1,自引:0,他引:1
Acetylcholine releases calcium from cytoplasmic stores and permits an influx of calcium in salivary acinar cells. The resultant rise in [Ca2+]i causes an increase in potassium permeability which is an important part of the secretory response. We have investigated the effects of 12-0-tetradecanoyl phorbol-13-acetate, a potent activator of protein kinase C, upon this regulation of potassium permeability in superfused pieces of rat submandibular salivary gland. This compound inhibited the initial [Ca2+]o-independent component of the response of acetylcholine but had no effect upon the subsequent [Ca2+]o-dependent phase. This compound does not, therefore, appear to inhibit receptor-regulated calcium influx. 相似文献
6.
P. C. Newell D. Malchow J. D. Gross 《Cellular and molecular life sciences : CMLS》1995,51(12):1155-1165
Changes in cytosolic Ca2+ play an important role in a wide array of cell types and the control of its concentration depends upon the interplay of many cellular constituents. Resting cells maintain cytosolic calcium ([Ca2+]i) at a low level in the face of steep gradients of extracellular and sequestered Ca2+. Many different signals can provoke the opening of calcium channels in the plasma membrane or in intracellular compartments and cause rapid influx of Ca2+ into the cytosol and elevation of [Ca2+]i. After such stimulation Ca2+ ATPases located in the plasma membrane and in the membranes of intracellular stores rapidly return [Ca2+]i to its basal level. Such responses to elevation of [Ca2+]i are a part of an important signal transduction mechanism that uses calcium (often via the binding protein calmodulin) to mediate a variety of cellular actions responsive to outside influences. 相似文献
7.
Summary The role of Ca2+ in secretagogue-induced insulin release is documented not only by the measurements of45Ca fluxes in pancreatic islets, but also, by direct monitoring of cytosolic free Ca2+, [Ca2+]i. As demonstrated, using the fluorescent indicator quin 2, glyceraldehyde, carbamylcholine and alanine raise [Ca2+]i in the insulin secreting cell line RINm5F, whereas glucose has a similar effect in pancreatic islet cells. The regulation of cellular Ca2+ homeostasis by organelles from a rat insulinoma, was investigated with a Ca2+ selective electrode. The results suggest that both the endoplasmic reticulum and the mitochondria participate in this regulation, albeit at different Ca2+ concentrations. By contrast, the secretory granules do not appear to be involved in the short-term regulation of [Ca2+]i. Evidence is presented that inositol 1,4,5-trisphosphate, which is shown to mobilize Ca2+ from the endoplasmic reticulum, is acting as an intracellular mediator in the stimulation of insulin release. 相似文献
8.
Summary Swimming speed of sea urchin spermatozoa, measured by a light scattering technique, did not change with 0-20 mM Ca2+ in the medium. The speed was maximum at the normal concentration of Mg2+ (49 mM) in sea water.Supported by grants-in-aid from the Ministry of Education, Science and Culture, Japan, and a grant from the Ford Foundation. 相似文献
9.
R. H. Evans A. A. Francis J. C. Watkins 《Cellular and molecular life sciences : CMLS》1977,33(4):489-491
Summary In the isolated frog or rat spinal cord, low concentrations of Mg2+ (0.5–1.00 mM) markedly depress, in a substantially Ca2+-independent manner, ventral root depolarizations produced by dorsal root stimulation and by certain amino acids (e. g. N-methyl-D-aspartate and L-homocysteate) but do not depress depolarizations produced by other excitatory amino acids (e. g. kainate and quisqualate). L-Aspartate-induced depolarizations are more sensitive to Mg2+ then are L-glutamate-induced depolarizations.Acknowledgment. We thank D. J. Oakes for skilled technica assistance. This work was supported by the Medical Research Council. 相似文献
10.
Wang SH Shih YL Ko WC Wei YH Shih CM 《Cellular and molecular life sciences : CMLS》2008,65(22):3640-3652
The cytotoxicity of cadmium (Cd) induced autophagy and apoptosis in MES-13 cells was determined by flow cytometry. Autophagy
was also assessed by formation of autophagosomes and processing of LC3. Pharmacological inhibition of autophagy resulted in
increased of cell viability, suggesting autophagy plays a role in cell death in Cd-treated mesangial cells. Cd also induced
a rapid elevation in cytosolic calcium ([Ca2+]i ), and modulation of [Ca2+]i via treatment with IP
3R inhibitor or knockdown of calcineurin resulted in a change in the proportion of cell death, suggesting that the release
of calcium from the ER plays a crucial role in Cd-induced cell death. Inhibition of Cd-induced ERK activation by PD 98059
suppressed Cd-induced autophagy, and BAPTA-AM eliminated activation of ERK. BAPTA-AM also inhibited Cd-induced mitochondrial
depolarization and activation of caspases. These findings demonstrated that Cd induces both autophagy and apoptosis through
elevation of [Ca2+]i, followed by Ca2+-ERK and Ca2+-mitochondria-caspase signaling pathways.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Received 05 July 2008; received after revision 25 August 2008; accepted 17 September 2008 相似文献
11.
Riassunto Mn2+ and Mg2+ attivano la piruvato cinasi di fegato di piccione in maniera distinta. In presenza di basse concentrationi di fosfoenolpiruvato Mn+ é piú efficace di Mg2+ ed é attivatore dell'enzima saturato da Mg2+. Piruvato cinasi (EC 2.7.1.40).
This work was supported by a grant from the Consiglio Nazionale delle Ricerche, Roma, Italia.Silvia Baldi is a fellow of the Italian C.N.R. 相似文献
This work was supported by a grant from the Consiglio Nazionale delle Ricerche, Roma, Italia.Silvia Baldi is a fellow of the Italian C.N.R. 相似文献
12.
C. J. Duncan 《Cellular and molecular life sciences : CMLS》1979,35(6):817-818
Summary The actions on amphibian embryos of UV-irradiation, exposure to Li+ or exposure to ouabain show interesting parallels with their effects on spontaneous release at the presynaptic terminals of the neuromuscular junction. It is suggested that these treatments serve to raise intracellular Ca2+ ([Ca2+
i) in these examples, and that UV-promoted abnormalities in embryogenesis are a consequence of changes in [Ca2+]i at critical stages in development. 相似文献
13.
Porcelli AM Ghelli A Mastrocola T Rugolo M 《Cellular and molecular life sciences : CMLS》1999,56(1-2):167-173
The Ca2+ ionophore ionomycin induced cytosolic [Ca2+]i elevation as well as strong activation of Cl− efflux in mouse mammary epithelial cell lines expressing wild-type or mutated (deletion of phenylalaline 508) cystic fibrosis
transmembrane conductance regulator (CFTR) or vector. Ionomycin-induced Cl− efflux was abolished by the intracellular Ca2+ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid, whereas both activators and inhibitors of phospholipase A2 had no effect, indicating the involvement of Ca2+-dependent Cl- channels. Stimulation of arachidonic acid release by ionomycin and phorbol ester was not significantly different between
wild-type or mutated cell lines, whereas vector-transfected cells exhibited a significant higher release, which was shown
to be due to larger amount of immunoreactive cytosolic phospholipase A2. These results indicate that phospholipase A2 activity of C127 cells was not influenced by the presence of wild-type or mutated CFTR.
Received 27 April 1999; received after revision 11 June 1999; accepted 23 July 1999 相似文献
14.
R. M. H. Ravindranath M. H. Ravindranath M. C. Graves 《Cellular and molecular life sciences : CMLS》1997,53(9):750-758
IgM antibodies directed against neuronal gangliosides GM1 , GM2 , GD1a , GD1b and GT1b occur in normal individuals and their level significantly decreases with age. Patients with lower motor neuron disease (LMND)
produce high levels of these autoantibodies. AntiGM1 IgM is selectively augmented. In these patients, the CD5+ (B1) and CD5− (B2) subsets of B cells are not distinct entities
but range from those without detectable CD5 marker to those with high CD5+ expression. B1 B cells were sorted to homogeneity,
but B2 B cell cannot be isolated to homogeneity because of the presence of B1 cells with low CD5 expression. In short term
cultures both the subsets produced IgM antibodies, but the antibodies reacted better with desialylated GM1 than with GM1 . Cycloheximide (Cx) (0.35 mM) largely blocked IgM synthesis of the B1 B cells but inhibition of the B2 B cells was incomplete,
possibly due to shedding of cytophilic antibodies as well as to the presence of B1 phenotype with loss of CD5 expression.
CD5+ B cells may be involved in the production of antiglycolipid IgM.
Received 9 June 1997; received after revision 21 July 1997; accepted 28 July 1997 相似文献
15.
S. L. Lee V. Havlicek A. E. Panerai H. G. Friesen 《Cellular and molecular life sciences : CMLS》1979,35(3):351-352
Summary Release of endogenous somatostatin (SRIF) from the rat cerebral cortical slices incubated in Krebs-bicarbonate buffer was increased from the basal rate of 3.4±0.6% of the total SRIF content in 15 min at [K+]o=5.6 mM, to 13.1±1.6% upon raising the [K+]o to 56.6 mM. The high-K+ evoked SRIF release was absent when Ca++ in the medium was replaced by Mn++. The isolated synaptosomes from rat cerebral cortex contain 13.2±3.1 ng SRIF/mg protein compared to 0.33±0.01 ng/mg protein in the cortical tissue as a whole, suggesting that nerve terminals are the main source of the peptide released upon membrane depolarization.The study was supported by a grant from the Medical Research Council of Canada. Results of this work have been published in part as abstracts: Can. Physiol.9, 45 (1978), and Fedn Proc.37, 665 (1978).The authors are greatly indebted to Dr M. Gotz and the Ayerst Research Laboratories for the most generous supply of the synthetic somatostatin. 相似文献
16.
C. M. Vázquez R. Coleto R. Zanetti V. Ruiz-Gutierrez 《Cellular and molecular life sciences : CMLS》1997,53(5):442-446
In the present study, we have examined the intestinal Na+ transport, through the Na+-H+ exchanger, in ileal brush-border membrane vesicles (BBMV) isolated from spontaneously hypertensive rats (SHR), and normotensive
Wistar Kyoto (WKY) rats as a control group. Na+ uptake into ileal BBMV was stimulated in the presence of a proton gradient (pH 5.5 inside/pH 7.5 outside) in SHR and WKY
rats, resulting in a transient accumulation (overshoot) in both groups of rats. No overshoot was observed in the absence of
a pH gradient. The magnitude of the accumulation was significantly higher in SHR than in WKY rats. Uptake of Na+ at equilibrium was identical in the presence and the absence of a proton gradient and was not changed in SHR. The use of
amiloride inhibited pH gradient-driven Na+ uptake in a dose-dependent manner with a Ki of 90 μM and 100 μM for SHR and WKY rats, respectively. The relationship between
proton gradient-driven Na+ uptake and external Na+ concentration was saturable and conformed to Michaelis-Menten kinetics in both SHR and WKY rats. Lineweaver-Burk analysis
of the pH gradient-driven Na+ uptake indicated values of Vmax that were significantly increased in SHR compared to WKY rats (11.4±0.55 nmol/mg/8 s vs. 4.96±0.78 nmol/mg/8 s for SHR and
WKY rats, respectively). In contrast, similar Km values for Na+ were found between SHR and WKY rats (4.0±0.2 mM vs. 4.9±0.6 mM for SHR and WKY rats, respectively). These studies show derangement
in ileal BBMV Na+ transport of SHR, which is characterized by increased Na+-H+ exchanger activity.
Received 18 December 1996; received after revision 3 February 1997; accepted 7 February 1997 相似文献
17.
Summary Smooth muscle, treated with 50% glycerol solution at 27°C for 20 min, contracted on the application of Ca2+ or Mg2+. The briefly glycerinated smooth muscle can be used as a model system of smooth muscle contraction. 相似文献
18.
Summary Cu2+-complexes with different monodentate ligands PYR, e.g. pyridine, 2,4,6-collidine and imidazole, catalyse the oxidation ofo-phenylenediamine (H2B) to 3,5-dihydro-2-amino-3-iminophenazine (PHEN) by O2. Investigation of the electron paramagnetic resonance during reaction gives interesting details on the function of Cu2+ as a catalyser. The formation of mixed complexes (H2B)Cu2+(PYR) and its influence on the reaction rated[PHEN]/dt is demonstrated. In the ratedetermining reaction, Cu2+ is reduced to Cu+, which is reoxidized by O2. During reaction the ratio [Cu2+]/[Cu+] is determined by means of e.p.r. measurements. 相似文献
19.
T. J. Rink 《Cellular and molecular life sciences : CMLS》1988,44(2):97-100
Experiments with permeabilised platelets, and with intact platelets loaded with fluorescent Ca2+-indicators, over the past several years have greatly extended our knowledge and understanding of cytosolic Ca2+ as a platelet activator and its interactions with other cytosolic regulators. This article outlines insights, gained from the use of the fluorescent dyes, into maintenance and restoration of basal [Ca2+]i, mechanisms of receptor-mediated Ca2+-mobilisation and quantitation of [Ca2+]i/response relations in intact human platelets. 相似文献
20.
Dekki N Refai E Holmberg R Köhler M Jörnvall H Berggren PO Juntti-Berggren L 《Cellular and molecular life sciences : CMLS》2012,69(10):1733-1743
Transthyretin (TTR) is a functional protein in the pancreatic β-cell. It promotes insulin release and protects against β-cell
death. We now demonstrate by ligand blotting, adsorption to specific magnetic beads, and surface plasmon resonance that TTR
binds to glucose-regulated proteins (Grps)78, 94, and 170, which are members of the endoplasmic reticulum chaperone family,
but Grps78 and 94 have also been found at the plasma membrane. The effect of TTR on changes in cytoplasmic free Ca2+ concentration ([Ca2+]i) was abolished if the cells were treated with either dynasore, a specific inhibitor of dynamin GTPase that blocks clathrin-mediated
endocytosis, or an antibody against Grp78, that prevents TTR from binding to Grp78. The conclusion is that TTR binds to Grp78
at the plasma membrane, is internalized into the β-cell via a clathrin-dependent pathway, and that this internalization is
necessary for the effects of TTR on β-cell function. 相似文献