Reversible mechanosensitive ion pumping as a part of mechanoelectrical transduction

V. S. Markin, T. Y. Tsong

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

To explain the ability of some mechanosensitive cells to reverse the process of mechanotransduction and to generate mechanical oscillations and emit sound, a piezo-conformational coupling model (PCC model) is proposed. The model includes a transport protein which changes either its volume (PV-coupling) or its area in the membrane (γA-coupling) when undergoing conformational transitions. Such a protein can interact with an oscillating pressure to pump ions and create a transmembrane gradient if the affinities of the protein for ions are different at the two sides of membrane. The frequency and concentration windows for mechanical energy transduction were determined. Under optimal conditions, the efficiency of energy transduction can approach the theoretical maximum of 100%. If the concentration gradient exceeds the static head value (quasi-equilibrium which can be built up and maintained by this transport system), the energy transduction reverses and the transporter becomes a generator of mechanical oscillations at the expense of a concentration gradient. Estimation of thermodynamic parameters of the pump shows that the PV-coupling model would require large pressure oscillations to work while the γA-coupling model could work in physiological conditions. The γA-coupling mechanism may be used by cells for two purposes. In the reverse mode, it can be a force generator for various applications. In the direct mode, it may serve bioenergetic purposes by harvesting the energy of mechanical oscillations and storing it in the form of a concentration gradient. This pump has an unusual thermodynamic feature: it can distinguish the two components of the electrochemical potential gradient, i.e., the concentration gradient and the electrical potential, the latter serving as a permissive switch to open, or close, the pump when the potential reaches the threshold value. Predictions of the PCC model and its probable involvement in biological mechanotransduction are discussed.

Original languageEnglish (US)
Pages (from-to)1317-1324
Number of pages8
JournalBiophysical Journal
Volume59
Issue number6
StatePublished - 1991

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Thermodynamics
Ion Pumps
Ions
Pressure
Membranes
Energy Metabolism
Carrier Proteins
Proteins

ASJC Scopus subject areas

  • Biophysics

Cite this

Reversible mechanosensitive ion pumping as a part of mechanoelectrical transduction. / Markin, V. S.; Tsong, T. Y.

In: Biophysical Journal, Vol. 59, No. 6, 1991, p. 1317-1324.

Research output: Contribution to journalArticle

Markin, V. S. ; Tsong, T. Y. / Reversible mechanosensitive ion pumping as a part of mechanoelectrical transduction. In: Biophysical Journal. 1991 ; Vol. 59, No. 6. pp. 1317-1324.
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