Changes of statistical structural fluctuations unveils an early compacted degraded stage of PNS myelin

Proper regulation of microtubule (MT) dynamics is critical for cellular processes including cell division and intracellular transport. Plus-end tracking proteins (+TIPs) dynamically track growing MTs and play a key role in MT regulation. +TIPs participate in a complex web of intra- and inter- molecular interactions known as the +TIP network. Hypotheses addressing the purpose of +TIP:+TIP interactions include relieving +TIP autoinhibition and localizing MT regulators to growing MT ends. In addition, we have proposed that the web of +TIP:+TIP interactions has a physical purpose: creating a dynamic scaffold that constrains the structural fluctuations of the fragile MT tip and thus acts as a polymerization chaperone. Here we examine the possibility that this proposed scaffold is a biomolecular condensate (i.e., liquid droplet). Many animal +TIP network proteins are multivalent and have intrinsically disordered regions, features commonly found in biomolecular condensates. Moreover, previous studies have shown that overexpression of the +TIP CLIP-170 induces large “patch” structures containing CLIP-170 and other +TIPs; we hypothesized that these structures might be biomolecular condensates. To test this hypothesis, we used video microscopy, immunofluorescence staining, and Fluorescence Recovery After Photobleaching (FRAP). Our data show that the CLIP-170-induced patches have hallmarks indicative of a biomolecular condensate, one that contains +TIP proteins and excludes other known condensate markers. Moreover, bioinformatic studies demonstrate that the presence of intrinsically disordered regions is conserved in key +TIPs, implying that these regions are functionally significant. Together, these results indicate that the CLIP-170 induced patches in cells are phase-separated liquid condensates and raise the possibility that the endogenous +TIP network might form a liquid droplet at MT ends or other +TIP locations.

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Breathing distortions in the metallic, antiferromagnetic phase of LaNiO$_3$

SciPost Physics ◽

10.21468/scipostphys.5.3.020 ◽

2018 ◽

Vol 5 (3) ◽

Cited By ~ 7

Author(s):

Alaska Subedi

Keyword(s):

Density Functional ◽

Recent Observation ◽

Quantum Critical Point ◽

Three Dimensional ◽

Density Functional Theory Calculations ◽

Antiferromagnetic Phase ◽

Functional Theory ◽

Antiferromagnetic Ordering ◽

Spin Polarized ◽

Structural Fluctuations

I study the structural and magnetic instabilities in LaNiO_33 using density functional theory calculations. From the non-spin-polarized structural relaxations, I find that several structures with different Glazer tilts lie close in energy. The PnmaPnma structure is marginally favored compared to the R\overline{3}cR3¯c structure in my calculations, suggesting the presence of finite-temperature structural fluctuations and a possible proximity to a structural quantum critical point. In the spin-polarized relaxations, both structures exhibit the \uparrow\!\!0\!\!\downarrow\!\!0↑0↓0 antiferromagnetic ordering with a rock-salt arrangement of the octahedral breathing distortions. The energy gain due to the breathing distortions is larger than that due to the antiferromagnetic ordering. These phases are semimetallic with small three-dimensional Fermi pockets, which is largely consistent with the recent observation of the coexistence of antiferromagnetism and metallicity in LaNiO_33 single crystals by Guo et al. [Nat. Commun. 9, 43 (2018)].

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Structural fluctuations in the steady state of muscular contraction

Biophysical Journal ◽

10.1016/s0006-3495(75)85845-0 ◽

1975 ◽

Vol 15 (7) ◽

pp. 633-649 ◽

Cited By ~ 11

Author(s):

F.D. Carlson

Keyword(s):

Steady State ◽

Muscular Contraction ◽

Structural Fluctuations

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The Fading of Memory During the Regression of Structural Fluctuations

Advances in Chemical Physics ◽

10.1002/9780470142875.ch3 ◽

2007 ◽

pp. 253-292 ◽

Cited By ~ 22

Author(s):

L. A. Dissado ◽

R. R. Nigmatullin ◽

R. M. Hill

Keyword(s):

Structural Fluctuations

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X-Ray Scattering and Solid-State Deuterium Nuclear Magnetic Resonance Probes of Structural Fluctuations in Lipid Membranes

Methods in Membrane Lipids - Methods in Molecular Biology™ ◽

10.1007/978-1-59745-519-0_23 ◽

2007 ◽

pp. 341-353 ◽

Cited By ~ 5

Author(s):

Horia I. Petrache ◽

Michael F. Brown

Keyword(s):

Nuclear Magnetic Resonance ◽

Solid State ◽

Magnetic Resonance ◽

Lipid Membranes ◽

X Ray ◽

X Ray Scattering ◽

Structural Fluctuations ◽

Nuclear Magnetic ◽

Ray Scattering

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Photophysical Properties of Spirobifluorene-Based o-Carboranyl Compounds Altered by Structurally Rotating the Carborane Cages

Molecules ◽

10.3390/molecules24224135 ◽

2019 ◽

Vol 24 (22) ◽

pp. 4135

Author(s):

Seonah Kim ◽

Hyunhee So ◽

Ji Hye Lee ◽

Hyonseok Hwang ◽

Hyoshik Kwon ◽

...

Keyword(s):

Radiative Decay ◽

Photophysical Properties ◽

High Energy ◽

Low Energy ◽

Radiative Decays ◽

Absorption Bands ◽

Molecular Features ◽

Td Dft ◽

Structural Fluctuations ◽

Energy Emissions

9,9′-Spirobifluorene-based o-carboranyl compounds C1 and C2 were prepared and fully characterized by multinuclear nuclear magnetic resonance (NMR) spectroscopy and elemental analysis. The solid-state structure of C1 was also determined by single-crystal X-ray diffractometry. The two carboranyl compounds display major absorption bands that are assigned to π−π* transitions involving their spirobifluorene groups, as well as weak intramolecular charge-transfer (ICT) transitions between the o-carboranes and their spirobifluorene groups. While C1 only exhibited high-energy emissions (λem = ca. 350 nm) in THF at 298 K due to locally excited (LE) states assignable to π−π* transitions involving the spirobifluorene group alone, a remarkable emission in the low-energy region was observed in the rigid state, such as in THF at 77 K or the film state. Furthermore, C2 displays intense dual emissive patterns in both high- and low-energy regions in all states. Electronic transitions that were calculated by time-dependent-DFT (TD-DFT) for each compound based on ground (S0) and first-excited (S1) state optimized structures clearly verify that the low-energy emissions are due to ICT-based radiative decays. Calculated energy barriers that are based on the relative energies associated with changes in the dihedral angle around the o-carborane cages in C1 and C2 clearly reveal that the o-carborane cage in C1 rotates more freely than that in C2. All of the molecular features indicate that ICT-based radiative decay is only available to the rigid state in the absence of structural fluctuations, in particular the free-rotation of the o-carborane cage.

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Schwannosis in Three Foals and a Calf

Veterinary Pathology ◽

10.1177/0300985819846872 ◽

2019 ◽

Vol 56 (5) ◽

pp. 783-788 ◽

Cited By ~ 2

Author(s):

Ileana C. Miranda ◽

Kyle R. Taylor ◽

William Castleman ◽

Alexander de Lahunta ◽

Brian A. Summers ◽

...

Keyword(s):

Spinal Cord ◽

Nervous System ◽

Schwann Cells ◽

Mass Effect ◽

Neurofibromatosis Type ◽

Proliferating Cells ◽

Pns Myelin ◽

The Central Nervous System ◽

Protein Zero

Proliferation of ectopic Schwann cells within the central nervous system (CNS) parenchyma (schwannosis) in early life is most commonly associated with human neurofibromatosis type-2 and has been unrecognized in domestic animals. Three foals and a calf, 5 to 11 weeks old, with progressive neurological signs from birth were studied. Histologically, at multiple levels of the spinal cord, all animals had bilateral plaques of proliferative spindle cells, predominantly affecting the white matter adjacent to dorsal and ventral nerve roots and variably extending into the gray matter. Proliferating cells had strong intracytoplasmic immunoreactivity for the Schwann cell markers myelin protein zero and periaxin, highlighting the formation of peripheral nervous system (PNS) myelin within the spinal cord. In all cases, foci of disorganized neural tissue (glioneuronal hamartomas) were present, which in 2 cases formed a mass effect that resulted in syringohydromyelia. Neonatal presentation suggests a congenital maldevelopment of the nervous system, with spontaneous invasion of PNS-derived Schwann cells into the CNS.

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