Disease relevance of Trdn

• Triadin overexpression stimulates excitation-contraction coupling and increases predisposition to cellular arrhythmia in cardiac myocytes [1].

High impact information on Trdn

• Immunofluorescence labeling of normal mouse myotubes shows that the RyR and triadin co-aggregate with the DHPR in punctate clusters upon formation of functional junctions [2].
• This change in Ca2+ spark amplitude distribution was not associated with any change in the density of ryanodine receptors, calsequestrin, junctin, triadin 1, Ca2+-ATPase, or phospholamban [3].
• We have cloned two new triadin isoforms from rat skeletal muscle, Trisk 49 and Trisk 32, which were named according to their theoretical molecular masses (49 and 32 kDa, respectively) [4].
• Overexpression did not modify the expression level of their protein partners ryanodine receptor, dihydropyridine receptor, and the other triadin [5].
• 1,4-Naphthoquinone (0.4-40 pmol/micrograms of protein) selectively oxidizes hyperreactive thiols on RyR and triadin and releases Ca2+ from SR vesicles, without inhibiting Ca(2+)-ATPase activity [6].

Biological context of Trdn

• That raises the question of whether CaM K II-mediated phosphorylation of alpha KAP and triadin together might be involved in a molecular signaling pathway important for SR Ca(2+)-release in fast-twitch muscle SR [7].

Anatomical context of Trdn

• Triadin (Trisk 95) overexpression blocks excitation-contraction coupling in rat skeletal myotubes [5].
• To define the functional role of TRD, we examined the effects of adenoviral-mediated overexpression of the wild-type protein (TRD(WT)) or a TRD mutant lacking the putative CASQ2 interaction domain residues 200 to 224 (TRD(Del.200-224)) on intracellular Ca signaling in adult rat ventricular myocytes [1].
• Western blots of muscle microsomes from preparations which had been treated with 100 mM iodoacetamide throughout the isolation procedure showed that cardiac triadin consisted predominantly of a band of M(r) 95 kD [8].
• Recently, a newly discovered 95-kDa protein, triadin, has been purified from rabbit skeletal muscle heavy sarcoplasmic reticulum (SR) vesicles [9].
• Immunofluorescence localization of triadin using mAb GE4.90 revealed that intact rat ventricular muscle tissue was stained following a well-defined pattern of bands every sarcomere [8].

Associations of Trdn with chemical compounds

• The results provide direct evidence of the existence and functional role of hyperreactive cysteine residues on the RyR and triadin in regulating the gating of ryanodine-sensitive intracellular Ca2+ channels and strongly suggest that these important Ca2+ regulatory channels may be an important target for oxidative cell damage mediated by quinones [6].
• Cardiac triadin was not dissolved from the microsomes by hypertonic salt or Triton X-100, indicating that it, as well as skeletal muscle triadin, was an integral protein of the junctional SR [8].

Other interactions of Trdn

• The monoclonal antibody GE4.90 against skeletal muscle triadin, a protein which links the DHP receptor to the junctional foot protein in skeletal muscle triad junctions, cross-reacted with a protein in rat dyads of the same M(r) as triadin [8].

Analytical, diagnostic and therapeutic context of Trdn

• Immunoprecipitation experiments with antiryanodine and antitriadin monoclonal antibodies confirm the location of CPM-labeled thiol groups on RyR and triadin, respectively [6].
• Immunostaining of Western blots showed no evidence of proteolysis of the RyR, the alpha 1-subunit of dihydropyridine receptor (DHPR) or triadin in uncoupled fibres [10].
• In addition, we have used indirect immunofluorescence to localize triadin in relation to the DHPR and the RyR in adult and developing rat skeletal muscle [9].

References