Biochemistry. 2003 Jan 21;42(2):450-7.

Polycystin-2 interacts with troponin I, an angiogenesis inhibitor.External 2231691f894ba696de1310221b0a0dbbb31a7251e75115c265587c3d9d5f507c

Li, Q., Shen, P. Y., Wu, G., Chen, X. Z.,
["Membrane Protein Research Group, Department of Physiology, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada."]
Polycystin-2 (PC2), encoded by the PKD2 gene, is mutated in 10-15% of autosomal dominant polycystic kidney disease (ADPKD) patients. PC2 is a Ca(2+)-permeable nonselective cation channel and is present in kidney and many other organs. Likewise, PKD2-mutated patients and mice exhibit extrarenal abnormalities. In comparison with cysts in the kidney, liver, and pancreas, abnormalities in the heart, brain, and vascular vessels are less understood. In particular, roles of PC2 in muscle and endothelia remain largely unknown. In the present study, using a yeast two-hybrid screening, we discovered that the PC2 carboxyl terminal domain (D682-V968) interacts with the cardiac troponin I, an important regulatory component of the actin microfilament in cardiac muscle cells. This interaction was demonstrated by GST pull-down and microtiter binding assays. Dose-dependent binding between PC2 and troponin I followed a Michaelis-Menten relationship, indicating a 1:1 binding stoichiometry. The interacting domains were located to the R872-H927 segment of PC2 and the M1-V107 and K106-L158 segments of troponin I. Co-immunoprecipitation experiments demonstrated that the cardiac and two skeletal isoforms of troponin I were all associated with PC2, when coexpressed in mouse fibroblast NIH 3T3 cells and Xenopus oocytes. Furthermore, reciprocal co-immunoprecipitation verified the interaction between the native polycystin-2 and troponin I in human adult heart tissues. This study thus provides new evidence for a direct attachment of PC2 to the actin microfilament network, in addition to the recently identified association between PC2 and trypomyosin-1. Troponin I functions as an inhibitory subunit of the troponin complex for calcium-dependent regulation of muscle contraction and as an inhibitor of angiogenesis seen in ADPKD. It is possible that altered interaction due to pathogenic polycystin-1 or -2 mutations can account for angiogenesis in ADPKD and may be corrected to some extent by exogenous troponin I.
PMID: 12525172External 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
TRPP1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 1 Inference Prediction 12525172
TRPP1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 2 Inference Prediction 12525172
TRPP1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 3 Yeast two-hybrid Human 682-968 Human Heart cDNA library 12525172
(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
TRPP1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 3 Fusion protein-pull down assay Human 682-968 E. coli Human Full-length E. coli 12525172
(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
TRPP1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 1 Co-immunoprecipitation NIH-3T3 Human Full-length Human Full-length 12525172
TRPP1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 1 Co-immunoprecipitation Xenopus oocyte Human Full-length Human Full-length 12525172
TRPP1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 2 Co-immunoprecipitation NIH-3T3 Human Full-length Human Full-length 12525172
TRPP1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 2 Co-immunoprecipitation Xenopus oocyte Human Full-length Human Full-length 12525172
TRPP1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 3 Co-immunoprecipitation NIH-3T3 Human Full-length Human Full-length 12525172
TRPP1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 3 Co-immunoprecipitation Xenopus oocyte Human Full-length Human Full-length 12525172
TRPP1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 3 Co-immunoprecipitation Human heart tissue 12525172
(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
TRPP1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 3 Yeast two-hybrid Human 872-927 Human 1-107 12525172
TRPP1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Troponin I 3 Yeast two-hybrid Human 872-927 Human 106-158 12525172
(Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4: click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)
TRP / Interactor

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