Related Experiment Videos
Modulation of K+ currents in human lymphocytes by pH
The Journal of Physiology
|June 1, 1989
Summary
Intracellular pH significantly impacts T lymphocyte potassium (K+) channels, enhancing their function at alkaline levels. This pH sensitivity is crucial for lymphocyte activation and volume regulation.
Area of Science:
- Immunology
- Cell Physiology
- Biophysics
Background:
- Voltage-dependent potassium (K+) channels play critical roles in T lymphocyte function.
- Intracellular pH (pHi) is a key regulator of cellular processes, including immune cell activation.
Purpose of the Study:
- To investigate the effect of intracellular pH on voltage-dependent K+ conductance in human peripheral blood T lymphocytes.
- To elucidate the mechanisms underlying pH sensitivity of these ion channels.
Main Methods:
- Whole-cell patch-clamp electrophysiology was employed to measure K+ currents.
- Single-channel recordings were performed to analyze channel behavior.
- Mathematical modeling was used to describe pH dependence.
Main Results:
- Alkaline pHi threefold enhanced voltage-dependent K+ conductance in T lymphocytes, described by a model with two proton binding sites (pKa 7.15).
- pHi did not affect channel activation/inactivation kinetics or voltage dependence.
- Extracellular pH (pHo) shifts activation thresholds and affects inactivation kinetics, suggesting surface charge screening.
Conclusions:
- Voltage-gated K+ conductance in T lymphocytes exhibits significant pH sensitivity, particularly to intracellular pH.
- This pH sensitivity is relevant for T lymphocyte mitogenesis and cellular volume regulation.
- The findings provide insights into the biophysical regulation of ion channels in immune cells.