EVIDENCE FOR A ROLE OF C-TERMINAL AMINO-ACID-RESIDUES IN SKELETAL-MUSCLE CA2+ RELEASE CHANNEL (RYANODINE RECEPTOR) FUNCTION

The effects of deleting 1, 3 and 15 amino acid residues from the highl y conserved C-terminus of the tetrameric skeletal muscle ryanodine rec eptor (RyR) complex were determined. Immunoblot analysis indicated sim ilar expression levels in HEK293 cells for full-length and mutant prot eins. Fun-length and RyR lacking the last amino acid showed (IH)-H-3]r yanodine binding and single channel activities typical of native recep tors. Deletion of 3 amino acids resulted in decreased activities, wher eas deletion of 15 amino acids yielded an inactive RyR. These results suggest that the most 15 C-terminal amino acids are important for the expression of a functional RyR complex. (C) 1997 Federation of Europea n Biochemical Societies.