Highly thermosensitive Ca dynamics in a HeLa cell through IP(3) receptors

Area of Science:

• Cell Biology
• Biophysics
• Physiology

Background:

• Intracellular calcium (Ca2+) distribution and dynamics are crucial for numerous cellular processes.
• Understanding the regulation of Ca2+ signaling under varying environmental conditions is essential.

Purpose of the Study:

• To investigate the impact of microscopic heat pulses on intracellular Ca2+ dynamics in single HeLa cells.
• To determine the thermosensitivity of Ca2+ signaling, particularly around physiological temperatures.

Main Methods:

• Utilized single-cell microscopy to observe Ca2+ distribution and flux in HeLa cells subjected to controlled heat pulses.
• Monitored Ca2+ uptake into intracellular stores during heating and Ca2+ release upon recooling.

Main Results:

• Microscopic heat pulses induced Ca2+ uptake during heating and Ca2+ release during recooling.
• An overshoot in Ca2+ release was observed above a critical temperature change, which decreased from 1.5 to 0.2 °C as experimental temperature increased from 22 to 37 °C.
• This thermosensitive Ca2+ dynamics is linked to the balance between endoplasmic reticulum Ca2+-ATPases and inositol 1,4,5-trisphosphate receptors.

Conclusions:

• Cellular Ca2+ signaling exhibits extreme sensitivity to temperature fluctuations, especially near body temperature.
• Cells expressing inositol 1,4,5-trisphosphate receptors demonstrate particularly heightened thermosensitivity in their Ca2+ dynamics.
• These findings highlight the importance of thermal stability for precise cellular function and Ca2+ signaling pathways.