J Invest Dermatol. 2005 Jan;124(1):187-97.
Phospholipase cgamma1 is required for activation of store-operated channels in human keratinocytes.
Tu, C. L., Chang, W., Bikle, D. D.,
["Endocrine Unit, Veteran Affairs Medical Center and Department of Medicine, University of California, San Francisco, California 94121, USA. ctu@itsa.ucsf.edu"]
["Endocrine Unit, Veteran Affairs Medical Center and Department of Medicine, University of California, San Francisco, California 94121, USA. ctu@itsa.ucsf.edu"]
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.
PMID: 15654973

![]() ![]() ![]() ![]() ![]() |
![]() |
Screening
![]() |
||||||||||
---|---|---|---|---|---|---|---|---|---|---|
Experimental screening | Non-experimental screening | Reference | ||||||||
TRP channel construct | Interactor source | |||||||||
TRP channel | Interactor | Method | Species | Region | Species | Organ/tissue | Sample type | |||
TRPC1 |
![]() |
PLCƣ1 | Inference | Prediction | 15654973 |
(
:
click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)

![]() ![]() ![]() ![]() ![]() |
![]() |
Validation: In vivo validation
![]() |
||||||||||
---|---|---|---|---|---|---|---|---|---|---|
Assay with endogenous proteins | Assay with overexpressed proteins | Reference | ||||||||
Cell or tissue | Cell or tissue | TRP channel construct | Interactor construct | |||||||
TRP channel | Interactor | Method | Species | Region | Species | Region | ||||
TRPC1 |
![]() |
IP3R3 | Co-immunoprecipitation | Human keratinocyte | 15654973 | |||||
TRPC1 |
![]() |
IP3R3 | Co-immunofluorescence staining | Human keratinocyte | 15654973 | |||||
TRPC1 |
![]() |
PLCƣ1 | Co-immunoprecipitation | Human keratinocyte | 15654973 | |||||
TRPC1 |
![]() |
PLCƣ1 | Co-immunofluorescence staining | Human keratinocyte | 15654973 |
(
:
click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)

![]() ![]() ![]() ![]() ![]() |
![]() |
Functional consequence
![]() |
||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
TRP channel | Interactor | Method | Post-translational modification | Subcellular trafficking | Activity | Reference | ||||||
TRPC1 |
![]() |
PLCƣ1 | Calcium measurement | Activation | 15654973 |
(
:
click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)
