Comparing ion conductance recordings of synthetic lipid bilayers with cell membranes containing TRP channels

Abstract

In this article we compare electrical conductance events from single channel recordings of three TRP channel proteins (TRPA1, TRPM2 and TRPM8) expressed in human embryonic kidney cells with channel events recorded on synthetic lipid membranes close to melting transitions. Ion channels from the TRP family are involved in a variety of sensory processes including thermo- and mechano-reception. Synthetic lipid membranes close to phase transitions display channel-like events that respond to stimuli related to changes in intensive thermodynamic variables such as pressure and temperature. TRP channel activity is characterized by typical patterns of current events dependent on the type of protein expressed. Synthetic lipid bilayers show a wide spectrum of electrical phenomena that are considered typical for the activity of protein ion channels. We find unitary currents, burst behavior, flickering, multistep-conductances, and spikes behavior in both preparations. Moreover, we report conductances and lifetimes for lipid channels as described for protein channels. Non-linear and asymmetric current-voltage relationships are seen in both systems. Without further knowledge of the recording conditions, no easy decision can be made whether short current traces originate from a channel protein or from a pure lipid membrane

13 pages, 9 Figures

References in corpus (7)

• The temperature dependence of lipid membrane permeability, its quantized nature, and the influence of anesthetics
• The thermodynamics of general anesthesia
• Lipid Ion Channels
• Phase state dependent current fluctuations in pure lipid membranes
• The influence of anesthetics, neurotransmitters and antibiotics on the relaxation processes in lipid membranes
• Ion-channel-like behavior in lipid bilayer membranes at the melting transition
• The thermodynamics of lipid ion channel formation in the absence and presence of anesthetics. BLM experiments and simulations

Cited by in corpus (8)

• The capacitance and electromechanical coupling of lipid membranes close to transitions. The effect of electrostriction
• Melting transitions in biomembranes
• Voltage-gated lipid ion channels
• Electrical properties of polar membranes
• The thermodynamics of general and local anesthesia
• The excitable fluid mosaic
• Nonlinear conductance, rectification and mechanosensitive channel formation of lipid membranes
• Lipid ion channels and the role of proteins