Oligomerization of the cardiac ryanodine receptor C-terminal tail.
The C-terminal 100 amino acids of the RyR (ryanodine receptor), referred to as the C-terminal tail, is a highly conserved sequence that is present in all known RyR isoforms and which has been implicated in channel function. Deleting the final 15 amino acids from the full-length skeletal muscle RyR resulted in an inactive channel, attributed to impaired assembly of a tetrameric RyR complex [Gao, Tripathy, Lu and Meissner (1997) FEBS Lett. 412, 223-226]. To account for these observations, the C-terminal tail itself may be an important molecular determinant of oligomerization. Alternatively, the large N-terminal cytoplasmic domain may fold back upon itself to interact with the C-terminal tail to provide a correctly folded tetrameric structure. We explored these possibilities for RyR2 (cardiac RyR) using the yeast two-hybrid interaction assay and in vitro translation followed by immunoprecipitation and chemical cross-linking. The data indicate that the C-terminal tail of RyR2 is capable of self-tetramerization. Moreover, a truncated C-terminal tail, lacking the final 15 amino acids, failed to self-associate. These observations suggest that the intrinsic ability of the RyR C-terminal tail to self-tetramerize may be vitally important for the oligomeric assembly of the native RyR channel.
Stewart
Richard
R
Wales Heart Research Institute, Department of Cardiology, University of Wales College of Medicine, Heath Park, Cardiff CF14 4XN, UK.
Zissimopoulos
Spyros
S
Lai
F Anthony
FA
D000595:Amino Acid Sequence; D003432:Cross-Linking Reagents; D009206:Myocardium / Q000737:chemistry*; D011233:Precipitin Tests; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D019837:Ryanodine Receptor Calcium Release Channel / Q000737:chemistry*; D017384:Sequence Deletion; D020798:Two-Hybrid System Techniques
D003432:Cross-Linking Reagents; D021122:Protein Subunits; D019837:Ryanodine Receptor Calcium Release Channel