کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1938502 | 1050741 | 2006 | 6 صفحه PDF | دانلود رایگان |
Triadin in the junctional sarcoplasmic reticulum (SR) of skeletal muscle cells has been suggested to interact with ryanodine receptor 1 (RYR1) via its KEKE motifs. Recently, we showed that amino acid residues D4878, D4907, and E4908 in RYR1 are critical for triadin-binding in vitro [J.M. Lee, S.H. Rho, D.W. Shin, C. Cho, W.J. Park, S.H. Eom, J. Ma, D.H. Kim, Negatively charged amino acids within the intraluminal loop of ryanodine receptor are involved in the interaction with triadin, J. Biol. Chem. 279 (2004) 6994–7000]. In order to test whether a disruption of the triadin-binding site(s) in RYR1 affects SR Ca2+ release, alanine-substituted single (D4878A, D4907A, and E4908A) and triple (RYR1-TM) mutants of D4878, D4907, and E4908 were expressed in RYR1-null myotubes. Co-immunoprecipitation experiments showed a 50–60% decrease of triadin brought down in the D4907A and RYR1-TM complexes compared to the triadin–wtRYR1 complex. Ca2+ imaging experiments using Fluo-4-AM showed atypical caffeine responses in myotubes expressing D4907A and RYR1-TM characterized by either a lack of or slower activation and faster inactivation of Ca2+ transients. The results suggest that disruption of interaction between triadin and RYR1 impairs RYR1 function and SR Ca2+ release.
Journal: Biochemical and Biophysical Research Communications - Volume 351, Issue 4, 29 December 2006, Pages 909–914