Cardiovasc Res. 2007 Jan 15;73(2):376-85. Epub 2006 Oct 27.
Insulin potentiates TRPC3-mediated cation currents in normal but not in insulin-resistant mouse cardiomyocytes.
Fauconnier, J., Lanner, J. T., Sultan, A., Zhang, S. J., Katz, A., Bruton, J. D., Westerblad, H.,
["Department of Physiology and Pharmacology, Karolinska Institutet, SE-171 77 Stockholm, Sweden."]
["Department of Physiology and Pharmacology, Karolinska Institutet, SE-171 77 Stockholm, Sweden."]
OBJECTIVE: Recent studies show that bioactive lipids alter intracellular Ca(2+) handling of cardiac cells differently in normal and insulin-resistant cardiomyocytes. In the present study we measured non-selective cation currents (NSCC) focusing on the interaction between insulin, the bioactive lipid diacylglycerol (DAG) and canonical transient receptor potential 3 (TRPC3) channels. METHODS: Whole cell patch-clamp was used to measure NSCC in ventricular cardiomyocytes isolated from adult wild-type (WT) and insulin resistant, obese ob/ob mice. Western blot, immunoprecipitation and immunofluorescence staining were used to study the concentration and cellular distribution of TRPC3 channels. RESULTS: Application of the membrane permeable DAG analogue (OAG, 30 microM) induced an NSCC, which was approximately 40% smaller in ob/ob than in WT cardiomyocytes. Insulin induced a small NSCC with similar amplitude in ob/ob and WT cells. Pretreatment with insulin (60 nM) increased the OAG-induced NSCC in WT (by approximately 50%) but not in ob/ob cells. OAG-induced currents were inhibited by adding anti-TRPC3 antibodies to the patch pipette solution. The expression of TRPC3 was lower in ob/ob than in WT cardiomyocytes. TRPC3 was detected in glucose transporter 4 (GLUT4) immunoprecipitates. Insulin exposure resulted in a translocation of TRPC3 to the plasma membrane in WT but not in ob/ob cardiomyocytes. CONCLUSIONS: Insulin-resistant ob/ob cardiomyocytes showed decreases in DAG-mediated NSCC, which were accompanied by decreased TRPC3 expression and defective insulin-mediated trafficking of this protein.
PMID: 17156765
 Screening
Validation: In vitro validation
Validation: In vivo validation
Characterization
Functional consequence
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Screening
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| Experimental screening | Non-experimental screening | Reference | ||||||||
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| TRP channel | Interactor | Method | Species | Region | Species | Organ/tissue | Sample type | |||
| TRPC3 |
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GLUT-4 | Inference | Prediction | 17156765 | |||||
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click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)
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click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)
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Screening
Validation: In vitro validation
Validation: In vivo validation
Characterization
Functional consequence
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top
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| Validation: In vivo validation
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| 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 | ||||
| TRPC3 |
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GLUT-4 | Co-immunoprecipitation | Mouse cardiomyocytes | 17156765 | |||||
(:
click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)
:
click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)