Dataset Information

Interaction of the Joining Region in Junctophilin-2 With the L-Type Ca²⁺ Channel Is Pivotal for Cardiac Dyad Assembly and Intracellular Ca²⁺ Dynamics.

ABSTRACT:

Rationale

Ca²⁺-induced Ca²⁺ release (CICR) in normal hearts requires close approximation of L-type calcium channels (LTCCs) within the transverse tubules (T-tubules) and RyR (ryanodine receptors) within the junctional sarcoplasmic reticulum. CICR is disrupted in cardiac hypertrophy and heart failure, which is associated with loss of T-tubules and disruption of cardiac dyads. In these conditions, LTCCs are redistributed from the T-tubules to disrupt CICR. The molecular mechanism responsible for LTCCs recruitment to and from the T-tubules is not well known. JPH (junctophilin) 2 enables close association between T-tubules and the junctional sarcoplasmic reticulum to ensure efficient CICR. JPH2 has a so-called joining region that is located near domains that interact with T-tubular plasma membrane, where LTCCs are housed. The idea that this joining region directly interacts with LTCCs and contributes to LTCC recruitment to T-tubules is unknown.

Objective

To determine if the joining region in JPH2 recruits LTCCs to T-tubules through direct molecular interaction in cardiomyocytes to enable efficient CICR.

Methods and results

Modified abundance of JPH2 and redistribution of LTCC were studied in left ventricular hypertrophy in vivo and in cultured adult feline and rat ventricular myocytes. Protein-protein interaction studies showed that the joining region in JPH2 interacts with LTCC-α1C subunit and causes LTCCs distribution to the dyads, where they colocalize with RyRs. A JPH2 with induced mutations in the joining region (mut^PG1JPH2) caused T-tubule remodeling and dyad loss, showing that an interaction between LTCC and JPH2 is crucial for T-tubule stabilization. mut^PG1JPH2 caused asynchronous Ca²⁺-release with impaired excitation-contraction coupling after β-adrenergic stimulation. The disturbed Ca²⁺ regulation in mut^PG1JPH2 overexpressing myocytes caused calcium/calmodulin-dependent kinase II activation and altered myocyte bioenergetics.

Conclusions

The interaction between LTCC and the joining region in JPH2 facilitates dyad assembly and maintains normal CICR in cardiomyocytes.

SUBMITTER: Gross P

PROVIDER: S-EPMC7790862 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Dataset Information

Interaction of the Joining Region in Junctophilin-2 With the L-Type Ca²⁺ Channel Is Pivotal for Cardiac Dyad Assembly and Intracellular Ca²⁺ Dynamics.

Rationale

Objective

Methods and results

Conclusions

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

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Dataset Information

Interaction of the Joining Region in Junctophilin-2 With the L-Type Ca2+ Channel Is Pivotal for Cardiac Dyad Assembly and Intracellular Ca2+ Dynamics.

Rationale

Objective

Methods and results

Conclusions

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Interaction of the Joining Region in Junctophilin-2 With the L-Type Ca²⁺ Channel Is Pivotal for Cardiac Dyad Assembly and Intracellular Ca²⁺ Dynamics.