Phosphorylation of the triadin cytoplasmic domain by CaM protein kinase in rabbit fast-twitch muscle sarcoplasmic reticulum

• Published in: Molecular and cellular biochemistry Vol. 223; no. 1-2; pp. 139 - 145
• Main Authors: Colpo, P, Nori, A, Sacchetto, R, Damiani, E, Margreth, A
• Format: Journal Article
• Language: English
• Published: Netherlands Springer Nature B.V 01.07.2001
• Subjects: Amino acids; Animals; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Calcium-Calmodulin-Dependent Protein Kinases - metabolism; Carrier Proteins - chemistry; Carrier Proteins - metabolism; Cytoplasmic Vesicles - metabolism; Genes, Reporter; Immunohistochemistry; Kinases; Membrane Proteins - chemistry; Membrane Proteins - metabolism; Muscle Fibers, Fast-Twitch - cytology; Muscle Fibers, Fast-Twitch - metabolism; Muscle Proteins - chemistry; Muscle Proteins - metabolism; Muscular system; Phosphorylation; Protein Structure, Tertiary; Proteins; Rabbits; Recombinant Fusion Proteins - metabolism; Sarcoplasmic Reticulum - enzymology; Sarcoplasmic Reticulum - metabolism
• ISSN: 0300-8177; 1573-4919
• DOI: 10.1023/A:1017987015807

Skeletal muscle triadin is a sarcoplasmic reticulum (SR) membrane protein that had been shown to interact structurally and functionally at the cytoplasmic domain (amino acid residues 1-47) with the ryanodine receptor (RyR1), and to undergo phosphorylation by endogenous calmodulin protein kinase (CaM K II) in isolated terminal cisternae from rabbit fast-twitch muscle. Here we show that triadin cytoplasmic domain expressed as glutathione-S-transferase fusion protein, is a substrate of the protein kinase. This finding is corroborated by identification of a specific consensus sequence in the deduced amino sequence between residue 34 and 37 of triadin. Confirming the regulatory features of CaM K II, we show the phosphorylation of triadin cytoplasmic segment by the kinase, when converted to the autonomous form. We propose that triadin modulates RyR1 in a phosphorylation-dependent manner.