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Calcium controls smooth muscle TRPC gene transcription via the CaMK/calcineurin-dependent pathways

Sara Morales1, Amalia Diez, Antonio Puyet

  • 1Department of Physiology, Nursing School, University of Extremadura, Avenida Universidad s/n, 10071 Cáceres, Spain.

American Journal of Physiology. Cell Physiology
|September 8, 2006
PubMed

Insights

Calcium levels regulate the expression of Transient Receptor Potential (TRP) channels in gallbladder smooth muscle. This study reveals how cellular calcium influences TRPC gene and protein abundance, impacting calcium homeostasis.

Area of Science:

  • Physiology
  • Molecular Biology
  • Biochemistry

Background:

  • Transient Receptor Potential (TRP) channels, particularly TRPC family members, are implicated in capacitative calcium entry (CCE).
  • The regulation of TRPC gene expression in response to cellular calcium levels remains largely uncharacterized.

Purpose of the Study:

  • To investigate the modulation of TRPC1-TRPC4 gene and protein expression by cytosolic calcium levels in guinea pig gallbladder smooth muscle.
  • To elucidate the signaling pathways involved in calcium-mediated regulation of TRPC expression.

Main Methods:

  • Quantitative analysis of TRPC1-TRPC4 mRNA and protein abundance under varying cytosolic calcium conditions.
  • Manipulation of intracellular calcium using chelators (EGTA, BAPTA AM) and activators (L-type Ca(2+) channels, intracellular Ca(2+) release).
  • Investigation of signaling pathways including Ca(2+)/calmodulin-dependent kinases (CaMK) and calcineurin.

Main Results:

  • Lowering cytosolic calcium downregulated TRPC1-TRPC4 gene and protein expression.
  • Increased cytosolic calcium via L-type channels or intracellular release upregulated TRPC1-TRPC4 mRNA and protein.
  • CaMK and calcineurin pathways were identified as crucial mediators in TRPC gene expression regulation.

Conclusions:

  • Cytosolic calcium levels exhibit an autoregulatory role in maintaining calcium homeostasis by controlling TRPC gene and protein expression.
  • This autoregulation involves CaMK and calcineurin signaling pathways, highlighting a feedback mechanism for calcium entry channels.

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