stevestory
Posts: 13407
Joined: Oct. 2005
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| Quote | 2
OLV June 14, 2019 at 12:09 am
“It has recently become clear that ribosomes are much more heterogeneous than previously thought, with diversity arising from rRNA sequence and modifications, ribosomal protein (RP) content and posttranslational modifications (PTMs), as well as bound nonribosomal proteins.”
Does functional specialization of ribosomes really exist?
Ferretti MB, Karbstein K
RNA. 2019 May;25(5):521-538. doi: 10.1261/rna.069823.118. Epub 2019 Feb 7.
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OLV June 14, 2019 at 12:33 am
Dlg1 activates beta-catenin signaling to regulate retinal angiogenesis and the blood-retina and blood-brain barriers
Chris Cho, Yanshu Wang, Philip M Smallwood, John Williams, Jeremy Nathans
DOI: 10.7554/eLife.45542
Beta-catenin (i.e., canonical Wnt) signaling controls CNS angiogenesis and the blood-brain and blood-retina barriers.
These data expand the repertoire of Dlg/MAGUK family functions to include a role in beta-catenin signaling, and they suggest that proteins other than Frizzled receptors interact with Dlg1 to enhance beta-catenin signaling.
In light of the evidence presented here that Dlg1 enhances beta-catenin signaling in CNS ECs, it seems reasonable to suggest that Dlg1 enhances beta-catenin signaling in other biological contexts and that part of the Dlg1-/- phenotype reflects this activity.
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OLV June 14, 2019 at 12:41 am
Drosophila FGF cleavage is required for efficient intracellular sorting and intercellular dispersal.
Sohr A1, Du L1, Wang R1, Lin L2, Roy S3.
J Cell Biol. 2019 May 6;218(5):1653-1669. doi: 10.1083/jcb.201810138. Epub 2019 Feb 26.
How morphogenetic signals are prepared for intercellular dispersal and signaling is fundamental to the understanding of tissue morphogenesis. We discovered an intracellular mechanism that prepares Drosophila melanogaster FGF Branchless (Bnl) for cytoneme-mediated intercellular dispersal during the development of the larval Air-Sac-Primordium (ASP). Wing-disc cells express Bnl as a proprotein that is cleaved by Furin1 in the Golgi. Truncated Bnl sorts asymmetrically to the basal surface, where it is received by cytonemes that extend from the recipient ASP cells. Uncleavable mutant Bnl has signaling activity but is mistargeted to the apical side, reducing its bioavailability. Since Bnl signaling levels feedback control cytoneme production in the ASP, the reduced availability of mutant Bnl on the source basal surface decreases ASP cytoneme numbers, leading to a reduced range of signal/signaling gradient and impaired ASP growth. Thus, enzymatic cleavage ensures polarized intracellular sorting and availability of Bnl to its signaling site, thereby determining its tissue-specific intercellular dispersal and signaling range.
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OLV June 14, 2019 at 12:48 am
Rapid translocation of pluripotency-related transcription factors by external uniaxial forces.
Topal T1,2, Kim BC1,2,3, Villa-Diaz LG2,4,5, Deng CX1, Takayama S1,2,6, Krebsbach PH2,4,7.
Integr Biol (Camb). 2019 Feb 26. pii: zyz003. doi: 10.1093/intbio/zyz003
Human embryonic stem cells subjected to a one-time uniaxial stretch for as short as 30-min on a flexible substrate coated with Matrigel experienced rapid and irreversible nuclear-to-cytoplasmic translocation of NANOG and OCT4, but not Sox2. Translocations were directed by intracellular transmission of biophysical signals from cell surface integrins to nuclear CRM1 and were independent of exogenous soluble factors. On E-CADHERIN-coated substrates, presumably with minimal integrin engagement, mechanical strain-induced rapid nuclear-to-cytoplasmic translocation of the three transcription factors. These findings might provide fundamental insights into early developmental processes and may facilitate mechanotransduction-mediated bioengineering approaches to influencing stem cell fate determination.
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OLV June 14, 2019 at 1:11 am
Feedback regulation of cytoneme-mediated transport shapes a tissue-specific FGF morphogen gradient
eLife. 2018; 7: e38137.
doi: 10.7554/eLife.38137
Lijuan Du,1 Alex Sohr,1 Ge Yan,1 and Sougata Roy1
Gradients of signaling proteins are essential for inducing tissue morphogenesis. However, mechanisms of gradient formation remain controversial.
These results reveal a robust mechanism where morphogens self-generate precise tissue-specific gradient contours through feedback regulation of cytoneme-mediated dispersion.
When an embryo develops, its cells must work together and ‘talk’ with each other so they can build the tissues and organs of the body.
How morphogens move in tissues to create gradients is still poorly understood.
Yet, it is still unclear how cytonemes can help to form gradients.
Despite advances in our understanding of signal transduction pathways, how signals disperse and how the dispersion mechanism is dynamically modulated to shape gradients in three-dimensional tissue structures are poorly understood. Moreover, the formation of signal gradients is unexplored in most morphogenetic contexts, so we do not know how dispersion of the signals through extracellular space can generate the required diversity in gradient shapes and contours for a multitude of tissue architectures.
How morphogen gradients are produced in tissues is a long-standing central question.
Given the commonality of fundamental signaling events mediated by conserved signaling proteins, feedback regulation of cytoneme-mediated transport may offer an explanation for why signal gradients are so precise, yet adaptable and for how diverse tissue morphologies can result from just one signal transduction pathway.
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OLV June 14, 2019 at 1:25 am
Imaging Cytonemes in Drosophila Embryos
Lijuan Du, Sougata Roy
Methods Mol Biol. 2018; 1863: 29–45. doi: 10.1007/978-1-4939-8772-6_3
Conserved morphogenetic signaling proteins disperse across tissues to generate signal and signaling gradients, which in turn are considered to assign positional coordinates to the recipient cells.
Recent imaging studies in Drosophila model have provided evidence for a “direct-delivery” mechanism of signal dispersion that is mediated by specialized actin-rich signaling filopodia, named cytonemes. Cytonemes establish contact between the signal-producing and target cells to directly exchange and transport the morphogenetic proteins.
the mechanisms by which signals disperse to form concentration gradients are poorly understood.
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OLV June 14, 2019 at 1:30 am
To the objectors asking about ID research:
Most biology-related discoveries published in serious research and review papers these days support ID.
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SteveO June 14, 2019 at 4:38 am
OLV
“Most biology-related discoveries published in serious research and review papers these days support ID.”
It seems to me that so much research – even if undertaken by materialists or crypto-materialists – is an obvious exercise in reverse engineering..
Scientists and engineers could fully describe the composition, function, and dynamics of an early Ford motor engine without having to mention Henry Ford if his name were taboo.
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OLV June 14, 2019 at 6:01 am
SteveO,
That’s a valid point. Thanks. |
Is this Dionisio under a new name or something?
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