On the Physical Basis of Biological Signaling by Interface Pulses

Fichtl, Bernhard; Silman, Israel; Schneider, Mat­thias

doi:10.1021/acs.langmuir.7b01613

Cited by 13 publications

(14 citation statements)

References 42 publications

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“…Our data shown here, in addition to the extensive studies on enzymes at lipid monolayers, further support the idea and might contribute to the discussion how this sensitivity of enzyme activity towards the membrane state can contribute to communication on the cellular level 38 , 40 .…”

Section: Discussionsupporting

confidence: 79%

“…This study is part of a series of publications establishing a new thermodynamic nerve signaling theory 39 , where the action potential is described by an acoustic-like pulse propagating laterally on the membrane. In the context of trigger- and detector potential of phase state sensitive enzymes at the synaptic cleft 40 , it would be of highest interest if the demonstrated phenomena also hold for bilayer associated enzymes.…”

Section: Introductionmentioning

confidence: 99%

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The activity of the intrinsically water-soluble enzyme ADAMTS13 correlates with the membrane state when bound to a phospholipid bilayer

Kamenac

Obser

Wixforth

et al. 2021

Sci Rep

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Membrane-associated enzymes have been found to behave differently qualitatively and quantitatively in terms of activity. These findings were highly debated in the 1970s and many general correlations and reaction specific models have been proposed, reviewed, and discarded. However, new biological applications brought up the need for clarification and elucidation. To address literature shortcomings, we chose the intrinsically water-soluble enzyme a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13) and large unilamellar vesicles with a relative broad phase transition. We here present activity measurements of ADAMTS13 in the freely dissolved state and the membrane associated state for phosphocholine lipids with different acyl-chain lengths (13:0, 14:0 and 15:0) and thus main phase transition temperatures. While the freely dissolved enzyme shows a simple Arrhenius behavior, the activity of membrane associated ADAMTS13 in addition shows a peak. This peak temperature correlates with the main phase transition temperature of the used lipids. These findings support an alternative theory of catalysis. This theory predicts a correlation of the membrane associated activity and the heat capacity, as both are susceptibilities of the same surface Gibb’s free energy, since the enzyme is attached to the membrane.

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Section: Discussionsupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

The activity of the intrinsically water-soluble enzyme ADAMTS13 correlates with the membrane state when bound to a phospholipid bilayer

Kamenac

Obser

Wixforth

et al. 2021

Sci Rep

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“…Ongoing evidences have advocated that pulse conduction is a macroscopic phenomenon that directly involves macroscopic structures such as the membrane and/or cytoskeleton [11][12][13]. We have hypothesized that the pulse propagation depends on the thermodynamic state of the interface of excitable biological system (e.g., plasma membrane), and we observed supporting evidences particularly concerning velocity, excitability, and nonlinearity [14][15][16]. Regarding the temperature-conduction relation, the hypothesis leads to the prediction that the relation is observed because temperature affects the state of the interface.…”

Section: Introductionsupporting

confidence: 70%

Nonlinear pulses at the interface and its relation to state and temperature

Kang

Schneider

2020

Eur. Phys. J. E

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Environmental temperature has a well-conserved effect on the pulse velocity and excitability of excitable biological systems. The consistency suggests that the cause originates from a fundamental principle. A physical (hydrodynamic) approach has proposed that the thermodynamic state of the hydrated interface (e.g., plasma membrane) determines the pulse behavior. This implies that the temperature effect happens because the environmental temperature affects the state of the interface in any given system. To test the hypothesis, we measured temperature-dependent phase diagrams of a lipid monolayer and studied the properties of nonlinear acoustic pulses excited along the membrane. We observed that the membrane in the fluid-gel transition regime exhibited lower compressibility (i.e., stiffer) overall with increasing temperature. Nonlinear pulses excited near the transition state propagated with greater velocity with increasing temperature, and these observations were consistent with the compressibility profiles. Excitability was suppressed significantly or ceased completely when the state departed too far from the transition regime either by cooling or by heating. The overall correlation between the pulses in the membrane and in living systems as a function of temperature supports the view that the thermodynamic state of the interface and phase transition are the key to understanding pulse propagation in excitable systems.

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“…To contribute to the discussion whether phase transitions in biological membranes play a role in the signaling mechanism of nerve cells [3,23,24] we analyzed B35 neuroblastoma cells and how their membrane order-disorder-transition is affected by differentiation and exposure to an anaesthetic. Applying the same concept as shown in figure 4 for HeLa cells, figure 5 shows GP as function of temperature, it´s derivative with respect to temperature in absence and presence of octanol and differentiated as well as undifferentiated.…”

Section: Neuroblastoma Cell Membrane After Differentiation and Anaesthetic Exposurementioning

confidence: 99%

Broad lipid phase transitions in mammalian cell membranes measured by Laurdan fluorescence spectroscopy

Färber

Westerhausen

2022

Biochimica et Biophysica Acta (BBA) - Biomembranes

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Employing fluorescence spectroscopy and the membrane-embedded dye Laurdan we experimentally show broad order-disorder-transitions in membranes of various cell lines and red blood cell ghosts. A custom-made setup allows for the determination of fluorescence spectra and the determination of the generalized polarization (GP) as a measure for membrane order in the temperature range of -40°C to +90°C of µl-volumes of cell suspension. While artificial lipid membranes like phosphatidylcholine show sharp transitions as known from calorimetry measurements, living cells in a physiological temperature range do only show linear changes in generalized polarization. However, extending the temperature range shows the existence of broad transitions and their sensitivity to cholesterol content, pH and anaesthetic. Moreover, adaptation to culture conditions like decreased temperature and morphological changes like detachment of adherent cells or dendrite growth are accompanied by changes in membrane order as well. The observed GP changes are equivalent to temperature changes dT in the range of -12K < dT <+6K.

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On the Physical Basis of Biological Signaling by Interface Pulses

Cited by 13 publications

References 42 publications

The activity of the intrinsically water-soluble enzyme ADAMTS13 correlates with the membrane state when bound to a phospholipid bilayer

The activity of the intrinsically water-soluble enzyme ADAMTS13 correlates with the membrane state when bound to a phospholipid bilayer

Nonlinear pulses at the interface and its relation to state and temperature

Broad lipid phase transitions in mammalian cell membranes measured by Laurdan fluorescence spectroscopy

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