Biochemistry. 2003 Jun 24;42(24):7618-25.

Troponin I binds polycystin-L and inhibits its calcium-induced channel activation.External 2231691f894ba696de1310221b0a0dbbb31a7251e75115c265587c3d9d5f507c

Li, Q., Liu, Y., Shen, P. Y., Dai, X. Q., Wang, S., Smillie, L. B., Sandford, R., Chen, X. Z.,
["Membrane Protein Research Group, Department of Physiology, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada."]
Polycystin-L (PCL) is an isoform of polycystin-2, the product of the second gene associated with autosomal dominant polycystic kidney disease, and functions as a Ca(2+)-regulated nonselective cation channel. We recently demonstrated that polycystin-2 interacts with troponin I, an important regulatory component of the actin microfilament complex in striated muscle cells and an angiogenesis inhibitor. In this study, using the two-microelectrode voltage-clamp technique and Xenopus oocyte expression system, we showed that the calcium-induced PCL channel activation is substantially inhibited by the skeletal and cardiac troponin I (60% and 31% reduction, respectively). Reciprocal co-immunoprecipitation experiments demonstrated that PCL physically associates with the skeletal and cardiac troponin I isoforms in overexpressed Xenopus oocytes and mouse fibroblast NIH 3T3 cells. Furthermore, both native PCL and cardiac troponin I were present in human heart tissues where they indeed associate with each other. GST pull-down and microtiter binding assays showed that the C-terminus of PCL interacts with the troponin I proteins. The yeast two-hybrid assay further verified this interaction and defined the corresponding interacting domains of the PCL C-terminus and troponin I. Taken together, this study suggests that troponin I acts as a regulatory subunit of the PCL channel complex and provides the first direct evidence that PCL is associated with the actin cytoskeleton through troponin I.
PMID: 12809519External 2231691f894ba696de1310221b0a0dbbb31a7251e75115c265587c3d9d5f507c
Screening Toggle 893349bafcc528f8346c51dc3420151d67b0126b2c122dd1017121c03fa0f69b
  Experimental screening Non-experimental screening Reference
TRP channel construct Interactor source
TRP channel Interactor Method Species Region Species Organ/tissue Sample type
TRPP2 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 1 Inference Prediction 12809519
TRPP2 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 2 Inference Prediction 12809519
TRPP2 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 3 Inference Prediction 12809519
(Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4: click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)
Validation: In vitro validation Toggle 893349bafcc528f8346c51dc3420151d67b0126b2c122dd1017121c03fa0f69b
  Assay with recombinant proteins Reference
TRP channel construct Interactor construct
TRP channel Interactor Method Species Region Expression system Species Region Expression system
TRPP2 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 1 Fusion protein-pull down assay Human 562-805 E. coli Human Not specified Not specified 12809519
TRPP2 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 2 Fusion protein-pull down assay Human 562-805 E. coli Human Not specified Not specified 12809519
TRPP2 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 3 Fusion protein-pull down assay Human 562-805 E. coli Human Not specified Not specified 12809519
(Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4: click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)
Validation: In vivo validation Toggle 893349bafcc528f8346c51dc3420151d67b0126b2c122dd1017121c03fa0f69b
  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
TRPP2 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 1 Co-immunoprecipitation NIH-3T3 Human Full-length Human Full-length 12809519
TRPP2 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 1 Co-immunoprecipitation Xenopus oocyte Human Full-length Human Full-length 12809519
TRPP2 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 2 Co-immunoprecipitation NIH-3T3 Human Full-length Human Full-length 12809519
TRPP2 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 2 Co-immunoprecipitation Xenopus oocyte Human Full-length Human Full-length 12809519
TRPP2 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 3 Co-immunoprecipitation NIH-3T3 Human Full-length Human Full-length 12809519
TRPP2 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 3 Co-immunoprecipitation Xenopus oocyte Human Full-length Human Full-length 12809519
TRPP2 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 3 Co-immunoprecipitation Human adult cardiac tissue 12809519
(Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4: click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)
Characterization Toggle 893349bafcc528f8346c51dc3420151d67b0126b2c122dd1017121c03fa0f69b
  Binding region mapping Stoichiometry Affinity (Kd) Reference
TRP channel Interactor
TRP channel Interactor Method Species Region Species Region
TRPP2 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 3 Yeast two-hybrid Human 630-705 Human Not determined 12809519
TRPP2 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 3 Yeast two-hybrid Human 562-805 Human 1-170 12809519
TRPP2 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 3 Yeast two-hybrid Human 562-805 Human 106-158 12809519
(Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4: click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)
Functional consequence Toggle 893349bafcc528f8346c51dc3420151d67b0126b2c122dd1017121c03fa0f69b
TRP channel Interactor Method Post-translational modification Subcellular trafficking Activity Reference
TRPP2 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 1 Calcium measurement Inhibition 12809519
TRPP2 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 1 Patch clamp Inhibition 12809519
TRPP2 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 3 Calcium measurement Inhibition 12809519
(Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4: click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)
TRP / Interactor

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