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Updated: Aug 7, 2026
Protein Isolation from the Developing Embryonic Mouse Heart Valve Region
Published on: September 23, 2014
Molecular cloning and characterization of mouse cardiac triadin isoforms
1Department of Life Science, Kwangju Institute of Science and Technology, 1 Oryong-dong, Puk-gu, Kwangju 500-712, South Korea.
Abstract:
Triadin is a ryanodine receptor and calsequestrin binding protein located in junctional sarcoplasmic reticulum of striated muscles. In the present study, mouse cardiac triadin cDNAs have been identified by cDNA library screening and RT-PCR. The deduced aa sequences show that the three isoforms consist of 277, 293 and 305 aa giving rise to the molecular weights of approximately 31,414, 33,066, and 34,328, respectively. The isoforms have identical 262 aa N-terminal sequences, whereas they have distinct C-terminal sequences. Northern blot analysis using a cDNA probe representing the N-terminal common region of triadin revealed that the mouse triadins were present both in heart and skeletal muscles. The estimated sizes of the transcripts were approximately 1.3, 4.3 and 5 kb in heart and 5, 5.5 and 7 kb in skeletal muscle. Endo H treatment and Western blot analysis of isolated mouse cardiac sarcoplasmic reticulum and in vitro translation products indicate that there are three distinct mouse cardiac triadin isoforms having molecular weights of 35, 35.5 and 40 kDa. We termed those three isoforms as mouse cardiac triadin 1, mouse cardiac triadin 2 and mouse cardiac triadin 3.
Insights
Researchers identified three distinct mouse cardiac triadin isoforms, crucial proteins in muscle function. These isoforms, varying in size and C-terminal sequences, are present in both heart and skeletal muscles, impacting muscle contraction regulation.
Area of Science:
- Molecular Biology
- Muscle Physiology
Background:
- Triadin is a key protein in striated muscles, binding to ryanodine receptors and calsequestrin within the sarcoplasmic reticulum.
- Understanding triadin's structure and function is vital for comprehending muscle excitation-contraction coupling.
Purpose of the Study:
- To identify and characterize mouse cardiac triadin isoforms.
- To investigate the expression patterns and molecular weights of these triadin isoforms.
Main Methods:
- cDNA library screening and RT-PCR were employed to identify mouse cardiac triadin cDNAs.
- Northern blot analysis was used to determine transcript sizes and tissue distribution.
- Endo H treatment and Western blot analysis were performed on cardiac sarcoplasmic reticulum and in vitro translation products.
Main Results:
- Three mouse cardiac triadin isoforms were identified, with deduced amino acid sequences of 277, 293, and 305 amino acids.
- These isoforms share an identical N-terminal sequence but possess distinct C-terminal regions.
- Northern blot analysis confirmed the presence of triadin transcripts in both heart and skeletal muscles, with varying transcript sizes.
- Western blot analysis revealed three distinct protein isoforms with molecular weights of 35, 35.5, and 40 kDa.
Conclusions:
- The study successfully identified and characterized three distinct mouse cardiac triadin isoforms (triadin 1, 2, and 3).
- These isoforms exhibit differential expression in cardiac and skeletal muscles, suggesting tissue-specific roles.
- The distinct C-terminal sequences may contribute to isoform-specific functions in muscle physiology.
