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951.
952.
A. Agata G?uszek C. Fiona Cullen Wenjing Li Rachel A. Battaglia Sarah J. Radford Mariana F. Costa Kim S. McKim Gohta Goshima Hiroyuki Ohkura 《The Journal of cell biology》2015,211(6):1113-1120
The critical step in meiosis is to attach homologous chromosomes to the opposite poles. In mouse oocytes, stable microtubule end-on attachments to kinetochores are not established until hours after spindle assembly, and phosphorylation of kinetochore proteins by Aurora B/C is responsible for the delay. Here we demonstrated that microtubule ends are actively prevented from stable attachment to kinetochores until well after spindle formation in Drosophila melanogaster oocytes. We identified the microtubule catastrophe-promoting complex Sentin-EB1 as a major factor responsible for this delay. Without this activity, microtubule ends precociously form robust attachments to kinetochores in oocytes, leading to a high proportion of homologous kinetochores stably attached to the same pole. Therefore, regulation of microtubule ends provides an alternative novel mechanism to delay stable kinetochore–microtubule attachment in oocytes. 相似文献
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955.
Muhammad Yasir Asghar Melissa Magnusson Kati Kemppainen Pramod Sukumaran Christoffer L?f Ilari Pulli Veronica Kalhori Kid T?rnquist 《The Journal of biological chemistry》2015,290(26):16116-16131
The identity of calcium channels in the thyroid is unclear. In human follicular thyroid ML-1 cancer cells, sphingolipid sphingosine 1-phosphate (S1P), through S1P receptors 1 and 3 (S1P1/S1P3), and VEGF receptor 2 (VEGFR2) stimulates migration. We show that human thyroid cells express several forms of transient receptor potential canonical (TRPC) channels, including TRPC1. In TRPC1 knockdown (TRPC1-KD) ML-1 cells, the basal and S1P-evoked invasion and migration was attenuated. Furthermore, the expression of S1P3 and VEGFR2 was significantly down-regulated. Transfecting wild-type ML-1 cells with a nonconducting TRPC1 mutant decreased S1P3 and VEGFR2 expression. In TRPC1-KD cells, receptor-operated calcium entry was decreased. To investigate whether the decreased receptor expression was due to attenuated calcium entry, cells were incubated with the calcium chelator BAPTA-AM (1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid). In these cells, and in cells where calmodulin and calmodulin-dependent kinase were blocked pharmacologically, S1P3 and VEGFR2 expression was decreased. In TRPC1-KD cells, both hypoxia-inducible factor 1α expression and the secretion and activity of MMP2 and MMP9 were attenuated, and proliferation was decreased in TRPC1-KD cells. This was due to a prolonged G1 phase of the cell cycle, a significant increase in the expression of the cyclin-dependent kinase inhibitors p21 and p27, and a decrease in the expression of cyclin D2, cyclin D3, and CDK6. Transfecting TRPC1 to TRPC1-KD cells rescued receptor expression, migration, and proliferation. Thus, the expression of S1P3 and VEGFR2 is mediated by a calcium-dependent mechanism. TRPC1 has a crucial role in this process. This regulation is important for the invasion, migration, and proliferation of thyroid cancer cells. 相似文献
956.
Melissa Richard-Greenblatt Horacio Bach John Adamson Sandra Pe?a-Diaz Wu Li Adrie J. C. Steyn Yossef Av-Gay 《The Journal of biological chemistry》2015,290(38):23064-23076
Ergothioneine (EGT) is synthesized in mycobacteria, but limited knowledge exists regarding its synthesis, physiological role, and regulation. We have identified Rv3701c from Mycobacterium tuberculosis to encode for EgtD, a required histidine methyltransferase that catalyzes first biosynthesis step in EGT biosynthesis. EgtD was found to be phosphorylated by the serine/threonine protein kinase PknD. PknD phosphorylates EgtD both in vitro and in a cell-based system on Thr213. The phosphomimetic (T213E) but not the phosphoablative (T213A) mutant of EgtD failed to restore EGT synthesis in a ΔegtD mutant. The findings together with observed elevated levels of EGT in a pknD transposon mutant during in vitro growth suggests that EgtD phosphorylation by PknD negatively regulates EGT biosynthesis. We further showed that EGT is required in a nutrient-starved model of persistence and is needed for long term infection of murine macrophages. 相似文献
957.
Xi Chen Kathrin Hnida Melissa Ann Graewert Jan Terje Andersen Rasmus Iversen Anne Tuukkanen Dmitri Svergun Ludvig M. Sollid 《The Journal of biological chemistry》2015,290(35):21365-21375
Antibodies to the autoantigen transglutaminase 2 (TG2) are a hallmark of celiac disease. We have studied the interaction between TG2 and an anti-TG2 antibody (679-14-E06) derived from a single gut IgA plasma cell of a celiac disease patient. The antibody recognizes one of four identified epitopes targeted by antibodies of plasma cells of the disease lesion. The binding interface was identified by small angle x-ray scattering, ab initio and rigid body modeling using the known crystal structure of TG2 and the crystal structure of the antibody Fab fragment, which was solved at 2.4 Å resolution. The result was confirmed by testing binding of the antibody to TG2 mutants by ELISA and surface plasmon resonance. TG2 residues Arg-116 and His-134 were identified to be critical for binding of 679-14-E06 as well as other epitope 1 antibodies. In contrast, antibodies directed toward the two other main epitopes (epitopes 2 and 3) were not affected by these mutations. Molecular dynamics simulations suggest interactions of 679-14-E06 with the N-terminal domain of TG2 via the CDR2 and CDR3 loops of the heavy chain and the CDR2 loop of the light chain. In addition there were contacts of the framework 3 region of the heavy chain with the catalytic domain of TG2. The results provide an explanation for the biased usage of certain heavy and light chain gene segments by epitope 1-specific antibodies in celiac disease. 相似文献
958.
Christopher L. Holley Melissa W. Li Benjamin S. Scruggs Scot J. Matkovich Daniel S. Ory Jean E. Schaffer 《The Journal of biological chemistry》2015,290(18):11741-11748
Small nucleolar RNAs (snoRNAs) guide nucleotide modifications of cellular RNAs in the nucleus. We previously showed that box C/D snoRNAs from the Rpl13a locus are unexpected mediators of physiologic oxidative stress, independent of their predicted ribosomal RNA modifications. Here we demonstrate that oxidative stress induced by doxorubicin causes rapid cytoplasmic accumulation of the Rpl13a snoRNAs through a mechanism that requires superoxide and a nuclear splice variant of NADPH oxidase. RNA-sequencing analysis reveals that box C/D snoRNAs as a class are present in the cytoplasm, where their levels are dynamically regulated by NADPH oxidase. These findings suggest that snoRNAs may orchestrate the response to environmental stress through molecular interactions outside of the nucleus. 相似文献
959.
Reduced dopamine and glutamate neurotransmission in the nucleus accumbens of quinpirole‐sensitized rats hints at inhibitory D2 autoreceptor function
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960.
We present the 174,935 nt long plastid genome of the red alga Laurencia sp. JFC0032. It is the third plastid genome characterized for the largest order of red algae (Ceramiales). The circular‐mapping plastid genome is small compared to most florideophyte red algae, and our comparisons show a trend toward smaller plastid genome sizes in the family Rhodomelaceae, independent from a similar trend in Cyanidiophyceae. The Laurencia genome is densely packed with 200 annotated protein‐coding genes (188 widely conserved, 3 open reading frames shared with other red algae and 9 hypothetical coding regions). It has 29 tRNAs, a single‐copy ribosomal RNA cistron, a tmRNA, and the RNase P RNA. 相似文献