Not so optimal: The evolution of mutual information in potassium voltage-gated channels

Abstract

Potassium voltage-gated (Kv) channels need to detect and respond to rapidly changing ionic concentrations in their environment. With an essential role in regulating electric signaling, they would be expected to be optimal sensors that evolved to predict the ionic concentrations. To explore these assumptions, we use statistical mechanics in conjunction with information theory to model how animal Kv channels respond to changes in potassium concentrations in their environment. By estimating mutual information in representative Kv channel types across a variety of environments, we find two things. First, under a wide variety of environments, there is an optimal gating current that maximizes mutual information between the sensor and the environment. Second, as Kv channels evolved, they have moved towards decreasing mutual information with the environment. This either suggests that Kv channels do not need to act as sensors of their environment or that Kv channels have other functionalities that interfere with their role as sensors of their environment.

Nonextensive realizations in interacting ion channels: Implications for mechano-electrical transducer mechanisms

“…However, studies involving isolated ion channels investigated the entropy, but situations involving cooperativity between channels rarely are reported in the literature. For instance, Duran and Marzen studied mutual information from the response of voltage-activated potassium channel (Kv) when the potassium concentration is modified ( [17]). In addition, Lewin et al studied entropy-based modulation of the Kv cluster ( [38]), while Portella et al investigated the effect of channel dependence on potassium ion permeation, concluding that entropy represents the major contribution to the permeation through the channel ( [49]).…”