Phospholipase cgamma1 is required for activation of store-operated channels in human keratinocytes

J Invest Dermatol. 2005 Jan;124(1):187-97. doi: 10.1111/j.0022-202X.2004.23544.x.


Store-operated calcium entry depicts the movement of extracellular Ca2+ into cells through plasma membrane Ca2+ channels activated by depletion of intracellular Ca2+ stores. The members of the canonical subfamily of transient receptor potential channels (TRPC) have been implicated as the molecular bases for store-operated channels (SOC). Here we investigate the role of phospholipase C (PLC) in regulation of native SOC and the expression of endogenous TRPC in human epidermal keratinocytes. Calcium entry in response to store depletion with thapsigargin was reversibly blocked by 2-aminoethoxydiphenyl borane, an effective SOC inhibitor, and suppressed by the diacylglycerol analoge, 1-oleoyl-2-acetyl-sn-glycerol. Inhibition of PLC with U73122 or transfection of a PLCgamma1 antisense cDNA construct completely blocked SOC activity, indicating a requirement for PLC, especially PLCgamma1, in the activation of SOC. RT-PCR and immunoblotting analyses showed that TRPC1, TRPC3, TRPC4, TRPC5, and TRPC6 are expressed in keratinocytes. Knockdown of the level of endogenous TRPC1 or TRPC4 inhibited store-operated calcium entry, indicating they are part of the native SOC. Co-immunoprecipitation studies demonstrated that TRPC1, but not TRPC4, interacts with PLCgamma1 and the inositol 1,4,5-trisphosphate receptor (IP3R). The association of TRPC1 with PLCgamma1 and IP3R decreased in keratinocytes with higher intracellular Ca2+, coinciding with a downregulation in SOC activity. Our results indicate that the activation of SOC in keratinocytes depends, at least partly, on the interaction of TRPC with PLCgamma1 and IP3R.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Calcium / metabolism*
  • Calcium Channels / genetics
  • Calcium Channels / metabolism*
  • Cells, Cultured
  • Cytosol / metabolism
  • DNA, Antisense
  • DNA, Complementary
  • Humans
  • Inositol 1,4,5-Trisphosphate Receptors
  • Ion Channels / genetics
  • Ion Channels / metabolism
  • Keratinocytes / cytology
  • Keratinocytes / enzymology*
  • Phospholipase C gamma
  • Receptors, Cytoplasmic and Nuclear / metabolism
  • TRPC Cation Channels
  • Transfection
  • Type C Phospholipases / genetics
  • Type C Phospholipases / metabolism*


  • Calcium Channels
  • DNA, Antisense
  • DNA, Complementary
  • ITPR1 protein, human
  • Inositol 1,4,5-Trisphosphate Receptors
  • Ion Channels
  • Receptors, Cytoplasmic and Nuclear
  • TRPC Cation Channels
  • TRPC4 ion channel
  • transient receptor potential cation channel, subfamily C, member 1
  • Type C Phospholipases
  • Phospholipase C gamma
  • Calcium