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91.
To address the role of gap junction hemichannels in apoptosis, the cell death induced by staurosporine (ST) was evaluated in wild type HeLa cells (HeLa-WT) and transfectants expressing either full-length connexin43 (HeLa-Cx43) or a C-terminal truncation of Cx43 (HeLa-DeltaCT). Cell death was measured with fluorescence-activated cell sorting (FACS), both DNA and nuclear fragmentation methods and assays for PARP and caspase 3. The ST-mediated cell death was accelerated in HeLa-Cx43 cells compared to HeLa-WT and HeLa-DeltaCT. To determine why HeLa-Cx43 cells were more susceptible to ST, the phosphorylation state and the localization of Cx43 protein within cells were examined using specific Cx43 antibodies. The phosphorylated forms of Cx43 were sharply reduced in HeLa-Cx43 cells treated with ST. Moreover, in ST-treated HeLa-Cx43 cells, Cx43 was mainly observed at the cell surface. In contrast, the truncated form of Cx43 found in HeLa-DeltaCT cells, which lacks many of the normal phosphorylation sites, was observed in the cytosol with ST treatment. To examine the hemichannels in the plasma membranes of ST-treated HeLa-Cx43 cells, several dye uptake methods using carboxyfluorescein and propidium iodide were employed. While the number of fluorescent cells did not change in HeLa-WT and HeLa-DeltaCT cells with ST treatment, the number of fluorescent HeLa-Cx43 cells increased more than ten-fold. These results indicate that the increases in cell surface Cx43 seen with immunofluorescence and the elevated hemichannel activities detected with dye uptake could help explain the accelerated cell death observed in ST-treated HeLa-Cx43 cells. 相似文献
92.
93.
Proteomic analysis of differentially expressed proteins induced by rice blast fungus and elicitor in suspension-cultured rice cells 总被引:1,自引:0,他引:1
We used two-dimensional electrophoresis (2-DE) and other proteomic approaches to identify proteins expressed in suspension-cultured rice cells in response to the rice blast fungus, Magnaporthe grisea. Proteins were extracted from suspension-cultured cells at 24 and 48 h after rice blast fungus inoculation or treatment with elicitor or other signal molecules such as jasmonic acid (JA), salicylic acid, and H(2)O(2). The proteins were then polyethylene glycol fractionated before separation by 2-DE. Fourteen protein spots were induced or increased by the treatments, which we analyzed by N-terminal or internal amino acid sequencing. Twelve proteins from six different genes were identified. Rice pathogen-related protein class 10 (OsPR-10), isoflavone reductase like protein, beta-glucosidase, and putative receptor-like protein kinase were among those induced by rice blast fungus; these have not previously been reported in suspension-cultured rice cells. Six isoforms of probenazole-inducible protein (PBZ1) and two isoforms of salt-induced protein (SalT) that responded to blast fungus, elicitor, and JA were also resolved on a 2-DE gel and identified by proteome analysis. The expression level of these induced proteins both in suspension-cultured cells and in leaves of whole plants was analyzed by Western blot. PBZ1, OsPR-10, and SalT proteins from incompatible reactions were induced earlier and to a greater extent than those in compatible reactions. Proteome analysis can thus distinguish differences in the timing and amount of protein expression induced by pathogens and other signal molecules in incompatible and compatible interactions. 相似文献
94.
Secretory low molecular weight phospholipase A2 plays important roles in cell elongation and shoot gravitropism in Arabidopsis
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Lee HY Bahn SC Kang YM Lee KH Kim HJ Noh EK Palta JP Shin JS Ryu SB 《The Plant cell》2003,15(9):1990-2002
To elucidate the cellular functions of phospholipase A(2) in plants, an Arabidopsis cDNA encoding a secretory low molecular weight phospholipase A(2) (AtsPLA(2)beta) was isolated. Phenotype analyses of transgenic plants showed that overexpression of AtsPLA(2)beta promotes cell elongation, resulting in prolonged leaf petioles and inflorescence stems, whereas RNA interference-mediated silencing of AtsPLA(2)beta expression retards cell elongation, resulting in shortened leaf petioles and stems. AtsPLA(2)beta is expressed in the cortical, vascular, and endodermal cells of the actively growing tissues of inflorescence stems and hypocotyls. AtsPLA(2)beta then is secreted into the extracellular spaces, where signaling for cell wall acidification is thought to occur. AtsPLA(2)beta-overexpressing or -silenced transgenic plants showed altered gravitropism in inflorescence stems and hypocotyls. AtsPLA(2)beta expression is induced rapidly by auxin treatment and in the curving regions of inflorescence stems undergoing the gravitropic response. These results suggest that AtsPLA(2)beta regulates the process of cell elongation and plays important roles in shoot gravitropism by mediating auxin-induced cell elongation. 相似文献
95.
Cho KI Lee JW Kim KS Lee EJ Suh JG Lee HJ Kim HT Hong SH Chung WH Chang KT Hyun BH Oh YS Ryoo ZY 《Comparative medicine》2003,53(6):642-648
Circling mice manifest profound deafness, head-tossing, and bi-directional circling behavior, which they inherit in autosomal recessive manner. Histologic examination of the inner ear reveals abnormalities of the region around the organ of Corti, spiral ganglion neurons, and outer hair cells. A genetic linkage map was constructed for an intraspecific backcross between cir and C57BL/6J mice. The cir gene was mapped to a region between D9Mit116/D9Mit15 and D9Mit38 on mouse chromosome (Chr) 9. Estimated distances between cir and D9Mit116, and between cir and D9Mit38 were 0.70 +/- 0.40 and 0.23 +/- 0.23 cM, respectively. Order of the markers was defined as follows: centromere - D9Mit182 - D9Mit51/D9Mit79/D9Mit310 - D9Mit212/D184 - D9Mit116/D9Mit15 - cir - D9Mit38 - D9Mit20 - D9Mit243 - D9Mit16 - D9Mit55/D9Mit125 - D9Mit281. On the basis of genetic mapping, we constructed a yeast artificial chromosome (YAC) contig across the cir region. The cir gene is located between the lactotransferrin (ltf) and microtubule-associated protein (map4) genes. The distal portion of mouse Chr 9 encompassing the cir region is homologous with human chromosome 3p21, which contains the Deafness, form B: Autosomal Recessive Deafness (DFNB6) locus. Therefore, the circling mouse is a potential animal model for DFNB6 deafness in humans. 相似文献
96.
Lee YM Kim BJ Kim HJ Yang DK Zhu MH Lee KP So I Kim KW 《American journal of physiology. Gastrointestinal and liver physiology》2003,284(4):G604-G616
We investigated which transient receptor potential (TRP) channel is responsible for the nonselective cation channel (NSCC) activated by carbachol (CCh) in murine stomach with RT-PCR and the electrophysiological method. All seven types of TRP mRNA were detected in murine stomach with RT-PCR. When each TRP channel was expressed, the current-voltage relationship of mTRP5 was most similar to that recorded in murine gastric myocytes. mTRP5 showed a conductance order of Cs(+) > K(+) > Na(+), similar to that in the murine stomach. With 0.2 mM GTPgammaS in the pipette solution, the current was activated transiently in both NSCC in the murine stomach and the expressed mTRP5. Both NSCC activated by CCh in murine stomach and mTRP5 were inhibited by intracellularly applied anti-G(q/11) antibody, PLC inhibitor U-73122, IICR inhibitor 2-aminoethoxydiphenylborate, and nonspecific cation channel blockers La(3+) and flufenamate. There were two other unique properties. Both the native NSCC and mTRP5 were activated by 1-oleoyl-2-acetyl-sn-glycerol. Without the activation of NSCC by CCh, the NSCC in murine stomach was constitutively active like mTRP5. From the above results, we suggest that mTRP5 might be a candidate for the NSCC activated by ACh or CCh in murine stomach. 相似文献
97.
Transmodulation between phospholipase D and c-Src enhances cell proliferation 总被引:4,自引:0,他引:4
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Ahn BH Kim SY Kim EH Choi KS Kwon TK Lee YH Chang JS Kim MS Jo YH Min DS 《Molecular and cellular biology》2003,23(9):3103-3115
Phospholipase D (PLD) has been implicated in the signal transduction pathways initiated by several mitogenic protein tyrosine kinases. We demonstrate for the first time that most notably PLD2 and to a lesser extent the PLD1 isoform are tyrosine phosphorylated by c-Src tyrosine kinase via direct association. Moreover, epidermal growth factor induced tyrosine phosphorylation of PLD2 and its interaction with c-Src in A431 cells. Interaction between these proteins is via the pleckstrin homology domain of PLD2 and the catalytic domain of c-Src. Coexpression of PLD1 or PLD2 with c-Src synergistically enhances cellular proliferation compared with expression of either molecule. While PLD activity as a lipid-hydrolyzing enzyme is not affected by c-Src, wild-type PLDs but not catalytically inactive PLD mutants significantly increase c-Src kinase activity, up-regulating c-Src-mediated paxillin phosphorylation and extracellular signal-regulated kinase activity. These results demonstrate the critical role of PLD catalytic activity in the stimulation of Src signaling. In conclusion, we provide the first evidence that c-Src acts as a kinase of PLD and PLD acts as an activator of c-Src. This transmodulation between c-Src and PLD may contribute to the promotion of cellular proliferation via amplification of mitogenic signaling pathways. 相似文献
98.
A Novel Technique for the Effective Production of Short Peptide Analogs from Concatameric Short Peptide Multimers 总被引:2,自引:0,他引:2
We designed a basic unit of the modified chicken gonadotropin releasing hormone II (cGnRH-II) peptide containing a trypsin cleavable linker peptide at both ends of the original peptide. We made a synthetic DNA coding for the modified cGnRH-II peptide with asymmetric and complementary cohesive ends of linker nucleotides. A tandemly repeated DNA cassette for the expression of concatameric short peptide multimers was constructed by ligating the basic units. The expressed peptide multimers were purified and subject to amino-terminal sequence analysis, which displayed the amino acid sequences expected from the designed nucleotides of the expression cassette. The monomeric cGnRH-II peptide analogs were generated after trypsin digestion. The present results showed that the technique developed for the production of the concatameric peptide multimers with cleavable linker peptides can be generally applicable to the production of short peptide analogs. 相似文献
99.
Sang‐Hwa Lee Yasuhito Sakuraba Taeyoung Lee Kyu‐Won Kim Gynheung An Han Yong Lee Nam‐Chon Paek 《植物学报(英文版)》2015,57(6):562-576
Jasmonic acid (JA) functions in plant development, including senescence and immunity. Arabidopsis thaliana CORONATINE INSENSITIVE 1 encodes a JA receptor and functions in the JA‐responsive signaling pathway. The Arabidopsis genome harbors a single COI gene, but the rice (Oryza sativa) genome harbors three COI homologs, OsCOI1a, OsCOI1b, and OsCOI2. Thus, it remains unclear whether each OsCOI has distinct, additive, synergistic, or redundant functions in development. Here, we use the oscoi1b‐1 knockout mutants to show that OsCOI1b mainly affects leaf senescence under senescence‐promoting conditions. oscoi1b‐1 mutants stayed green during dark‐induced and natural senescence, with substantial retention of chlorophylls and photosynthetic capacity. Furthermore, several senescence‐associated genes were downregulated in oscoi1b‐1 mutants, including homologs of Arabidopsis thaliana ETHYLENE INSENSITIVE 3 and ORESARA 1, important regulators of leaf senescence. These results suggest that crosstalk between JA signaling and ethylene signaling affects leaf senescence. The Arabidopsis coi1‐1 plants containing 35S:OsCOI1a or 35S:OsCOI1b rescued the delayed leaf senescence during dark incubation, suggesting that both OsCOI1a and OsCOI1b are required for promoting leaf senescence in rice. oscoi1b‐1 mutants showed significant decreases in spikelet fertility and grain weight, leading to severe reduction of grain yield, indicating that OsCOI1‐mediated JA signaling affects spikelet fertility and grain filling. 相似文献
100.
Hyung Woo Kim Geun Woo Ryu Cheol Ho Park Ea Wha Kang Jung Tak Park Seung Hyeok Han Tae-Hyun Yoo Sug Kyun Shin Shin-Wook Kang Kyu Hun Choi Dae Suk Han Tae Ik Chang 《PloS one》2015,10(6)