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Dynamics of receptor-operated Ca(2+) currents through TRPC channels controlled via the PI(4,5)P2-PLC signaling

Masayuki X Mori1, Kyohei Itsuki2, Hideharu Hase1

  • 1Department of Synthetic and Biological Chemistry, School of Engineering, Kyoto University Kyoto, Japan.

Frontiers in Pharmacology
|February 27, 2015
PubMed

Insights

Transient receptor potential canonical (TRPC) channels regulate vascular function through receptor-operated Ca2+ currents (ROCs). New research clarifies the complex, bidirectional role of PI(4,5)P2 in TRPC channel regulation and ROCs.

Area of Science:

  • Physiology
  • Molecular Biology
  • Biophysics

Background:

  • Transient receptor potential canonical (TRPC) channels are crucial for Ca2+ influx in vascular smooth muscle cells, mediating depolarization, vasoconstriction, and remodeling.
  • Receptor-operated Ca2+ currents (ROCs) through TRPC channels are triggered by phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) hydrolysis.
  • The precise regulatory mechanisms of TRPC channel activity and ROCs by PI(4,5)P2 and its metabolites remain incompletely understood.

Purpose of the Study:

  • To elucidate the complex and potentially bidirectional regulation of TRPC channels and ROCs by PI(4,5)P2 and its metabolites.
  • To investigate the dynamic contribution of PI(4,5)P2 to TRPC channel activity and transmembrane ion flow.
  • To provide insight into the fundamental mechanisms governing vascular TRPC channel function.

Main Methods:

  • Utilized voltage-sensing phosphoinositide phosphatases to probe PI(4,5)P2 dynamics.
  • Employed model simulations to analyze the time-dependent effects of PI(4,5)P2 on TRPC channel activity.
  • Reviewed existing literature on TRPC channel regulation and receptor-mediated signaling.

Main Results:

  • Demonstrated the differential effects of PI(4,5)P2 and its metabolites on TRPC channel activity.
  • Revealed the time-dependent contribution of PI(4,5)P2 in regulating ROCs.
  • Model simulations provided explanations for the controversial bidirectional effects of PI(4,5)P2 on various ROCs.

Conclusions:

  • PI(4,5)P2 plays a complex, bidirectional role in regulating TRPC channels and ROCs.
  • Voltage-sensing phosphoinositide phosphatases and model simulations are powerful tools for studying phosphoinositide regulation of ion channels.
  • Understanding these regulatory dynamics is key to deciphering transmembrane ion flow and vascular function.
Keywords:
Ca2+ signalingPIP2TRPC channelsreceptor-operated calcium currentsmooth musclevoltage-sensing phosphatase

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