title: Phosphorylation of the triadin cytoplasmic domain by CaM protein kinase in rabbit fast-twitch muscle sarcoplasmic reticulum.
abstract: 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.
authors.affiliation: Department of Experimental Biomedical Sciences, University of Padova, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Colpo
authors.forename: A
authors.initials: A
authors.lastname: Nori
authors.forename: R
authors.initials: R
authors.lastname: Sacchetto
authors.forename: E
authors.initials: E
authors.lastname: Damiani
authors.forename: A
authors.initials: A
authors.lastname: Margreth
mesh_terms: D000818:Animals; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D022162:Cytoplasmic Vesicles / Q000378:metabolism; D017930:Genes, Reporter; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism; D018656:Muscle Fibers, Fast-Twitch / Q000166:cytology / Q000378:metabolism*; D009124:Muscle Proteins / Q000737:chemistry / Q000378:metabolism*; D010766:Phosphorylation; D017434:Protein Structure, Tertiary; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012519:Sarcoplasmic Reticulum / Q000201:enzymology / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D008565:Membrane Proteins; D009124:Muscle Proteins; D011993:Recombinant Fusion Proteins; C070048:triadin; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases