Calcium signal transmission by axonemal microtubules as an optimized information pathway in cilia and flagella

2021 ◽  
Author(s):  
M. V. Satarić ◽  
T. Nemeš ◽  
B. M. Satarić
Keyword(s):  
Signal Transmission ◽  
Calcium Signal ◽  
Cilia And Flagella

scholarly journals Chemically-induced Neurite-like Outgrowth Reveals Multicellular Network Function in Patient-derived Glioblastoma Cells

2018 ◽  
Author(s):  
Barbara da Silva ◽  
Euan S. Polson ◽  
Alastair Droop ◽  
Ryan K. Mathew ◽  
Lucy F. Stead ◽  
...  
Keyword(s):  
De Novo ◽  
Ex Vivo ◽  
Signal Transmission ◽  
Calcium Signal ◽  
High Dose ◽  
Connected Vehicle ◽  
Network Function ◽  
Small Molecule Inhibition ◽  
Chemically Induced ◽  
Radiation Resistant

SummaryTumor stem cells and malignant multicellular networks have been separately implicated in the therapeutic resistance of Glioblastoma Multiforme (GBM), the most aggressive type of brain cancer in adults. We show that small molecule inhibition of RHO-associated serine/threonine kinase (ROCKi) significantly promoted the outgrowth of neurite-like cell projections in cultures of heterogeneous patient-derived GBM stem-like cells. These projections formedde novo-induced cellular network (iNet) ‘webs’, which regressed after withdrawal of ROCKi. Connected cells within the iNet web exhibited long range calcium signal transmission, and significant lysosomal and mitochondrial trafficking. In contrast to their less-connected vehicle control counterparts, iNet cells remained viable and proliferative after high-dose radiation. These findings demonstrate a link between ROCKi-regulated cell projection dynamics and the formation of radiation-resistant multicellular networks. Our study identifies means to reversibly induce iNet websex vivo, and may thereby accelerate future studies into the biology of GBM cellular networks.

scholarly journals Calcium Signal Transmission between Ryanodine Receptors and Mitochondria

2000 ◽  
Vol 275 (20) ◽  
pp. 15305-15313 ◽  
Author(s):  
Gábor Szalai ◽  
György Csordás ◽  
Basil M. Hantash ◽  
Andrew P. Thomas ◽  
György Hajnóczky
Keyword(s):  
Signal Transmission ◽  
Ryanodine Receptors ◽  
Calcium Signal

Calcium signal transmission in chick sensory neurones is diffusion based

Cell Calcium ◽  
2008 ◽  
Vol 43 (3) ◽  
pp. 236-249 ◽  
Author(s):  
William Coatesworth ◽  
Stephen Bolsover
Keyword(s):  
Signal Transmission ◽  
Calcium Signal ◽  
Sensory Neurones

scholarly journals Quantification of calcium signal transmission from sarco‐endoplasmic reticulum to the mitochondria

2000 ◽  
Vol 529 (3) ◽  
pp. 553-564 ◽  
Author(s):  
Pál Pacher ◽  
György Csordás ◽  
Timothy G. Schneider ◽  
György Hajnóczky
Keyword(s):  
Endoplasmic Reticulum ◽  
Signal Transmission ◽  
Calcium Signal

Study of eukaryotic flagellar components by cryo-electron microscopy

1986 ◽  
Vol 44 ◽  
pp. 98-101
Author(s):  
John M. Murray ◽  
Rob Ward
Keyword(s):  
Electron Microscopy ◽  
Primary Motion ◽  
Cryo Electron Microscopy ◽  
Cross Links ◽  
Cilia And Flagella

The eukaryotic flagellum is constructed from 11 parallel tubular elements arranged as 9 peripheral fibers (doublet microtubules) and 2 central fibers (singlet microtubules). The primary motion generating component has been found to be arranged as axially periodic “arms” bridging the adjacent doublets. The dynein, comprising the arms, has been isolated and characterized from several different cilia and flagella. Various radial and azimuthal cross-links stabilize the axially aligned microtubules, and probably play some role in controlling the form of the flagella beat cycle.

Observations of Frozen-Hydrated Microtubules

1990 ◽  
Vol 48 (1) ◽  
pp. 504-505
Author(s):  
D. Chrétien ◽  
D. Job ◽  
R.H. Wade
Keyword(s):  
Fourier Transforms ◽  
Structural Complexity ◽  
Image Contrast ◽  
Phase Behaviour ◽  
Experimental Conditions ◽  
Thin Sections ◽  
Surface Lattice ◽  
Cilia And Flagella ◽  
Outstanding Question

Microtubules are filamentary structures found in the cytoplasm of eukaryotic cells, where, together with actin and intermediate filaments, they form the components of the cytoskeleton. They have many functions and show various levels of structural complexity as witnessed by the singlet, doublet and triplet structures involved in the architecture of centrioles, basal bodies, cilia and flagella. The accepted microtubule model consists of a 25 nm diameter hollow tube with a wall made up of 13 paraxial protofilaments (pf). Each pf is a string of aligned tubulin dimers. Some results have suggested that the pfs follow a superhelix. To understand how microtubules function in the cell an accurate model of the surface lattice is one of the requirements. For example the 9x2 architecture of the axoneme will depend on the organisation of its component microtubules. We should also note that microtubules with different numbers of pfs have been observed in thin sections of cellular and of in-vitro material. An outstanding question is how does the surface lattice adjust to these different pf numbers?We have been using cryo-electron microscopy of frozen-hydrated samples to study in-vitro assembled microtubules. The experimental conditions are described in detail in this reference. The results obtained in conjunction with thin sections of similar specimens and with axoneme outer doublet fragments have already allowed us to characterise the image contrast of 13, 14 and 15 pf microtubules on the basis of the measured image widths, of the the image contrast symmetry and of the amplitude and phase behaviour along the equator in the computed Fourier transforms. The contrast variations along individual microtubule images can be interpreted in terms of the geometry of the microtubule surface lattice. We can extend these results and make some reasonable predictions about the probable surface lattices in the case of other pf numbers, see Table 1. Figure 1 shows observed images with which these predictions can be compared.

Introductory Remarks

1980 ◽  
Vol 38 ◽  
pp. 598-599
Author(s):  
H. Mohri
Keyword(s):  
Muscle Contraction ◽  
Experimental Evidence ◽  
Sea Urchin ◽  
Constant Length ◽  
Thin Filaments ◽  
Bridge Formation ◽  
Thick Filaments ◽  
Sliding Mechanism ◽  
Radial Spokes ◽  
Cilia And Flagella

In 1959, Afzelius observed the presence of two rows of arms projecting from each outer doublet microtubule of the so-called 9 + 2 pattern of cilia and flagella, and suggested a possibility that the outer doublet microtubules slide with respect to each other with the aid of these arms during ciliary and flagellar movement. The identification of the arms as an ATPase, dynein, by Gibbons (1963)strengthened this hypothesis, since the ATPase-bearing heads of myosin molecules projecting from the thick filaments pull the thin filaments by cross-bridge formation during muscle contraction. The first experimental evidence for the sliding mechanism in cilia and flagella was obtained by examining the tip patterns of molluscan gill cilia by Satir (1965) who observed constant length of the microtubules during ciliary bending. Further evidence for the sliding-tubule mechanism was given by Summers and Gibbons (1971), using trypsin-treated axonemal fragments of sea urchin spermatozoa. Upon the addition of ATP, the outer doublets telescoped out from these fragments and the total length reached up to seven or more times that of the original fragment. Thus, the arms on a certain doublet microtubule can walk along the adjacent doublet when the doublet microtubules are disconnected by digestion of the interdoublet links which connect them with each other, or the radial spokes which connect them with the central pair-central sheath complex as illustrated in Fig. 1. On the basis of these pioneer works, the sliding-tubule mechanism has been established as one of the basic mechanisms for ciliary and flagellar movement.

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