Phosphoregulation of the titin-cap protein telethonin in cardiac myocytes
Standard
Phosphoregulation of the titin-cap protein telethonin in cardiac myocytes. / Candasamy, Alexandra J; Haworth, Robert S; Cuello, Friederike; Ibrahim, Michael; Aravamudhan, Sriram; Krüger, Marcus; Holt, Mark R; Terracciano, Cesare M N; Mayr, Manuel; Gautel, Mathias; Avkiran, Metin.
in: J BIOL CHEM, Jahrgang 289, Nr. 3, 17.01.2014, S. 1282-1293.Publikationen: SCORING: Beitrag in Fachzeitschrift/Zeitung › SCORING: Zeitschriftenaufsatz › Forschung › Begutachtung
Harvard
APA
Vancouver
Bibtex
}
RIS
TY - JOUR
T1 - Phosphoregulation of the titin-cap protein telethonin in cardiac myocytes
AU - Candasamy, Alexandra J
AU - Haworth, Robert S
AU - Cuello, Friederike
AU - Ibrahim, Michael
AU - Aravamudhan, Sriram
AU - Krüger, Marcus
AU - Holt, Mark R
AU - Terracciano, Cesare M N
AU - Mayr, Manuel
AU - Gautel, Mathias
AU - Avkiran, Metin
PY - 2014/1/17
Y1 - 2014/1/17
N2 - Telethonin (also known as titin-cap or t-cap) is a muscle-specific protein whose mutation is associated with cardiac and skeletal myopathies through unknown mechanisms. Our previous work identified cardiac telethonin as an interaction partner for the protein kinase D catalytic domain. In this study, kinase assays used in conjunction with MS and site-directed mutagenesis confirmed telethonin as a substrate for protein kinase D and Ca(2+)/calmodulin-dependent kinase II in vitro and identified Ser-157 and Ser-161 as the phosphorylation sites. Phosphate affinity electrophoresis and MS revealed endogenous telethonin to exist in a constitutively bis-phosphorylated form in isolated adult rat ventricular myocytes and in mouse and rat ventricular myocardium. Following heterologous expression in myocytes by adenoviral gene transfer, wild-type telethonin became bis-phosphorylated, whereas S157A/S161A telethonin remained non-phosphorylated. Nevertheless, both proteins localized predominantly to the sarcomeric Z-disc, where they partially replaced endogenous telethonin. Such partial replacement with S157A/S161A telethonin disrupted transverse tubule organization and prolonged the time to peak of the intracellular Ca(2+) transient and increased its variance. These data reveal, for the first time, that cardiac telethonin is constitutively bis-phosphorylated and suggest that such phosphorylation is critical for normal telethonin function, which may include maintenance of transverse tubule organization and intracellular Ca(2+) transients.
AB - Telethonin (also known as titin-cap or t-cap) is a muscle-specific protein whose mutation is associated with cardiac and skeletal myopathies through unknown mechanisms. Our previous work identified cardiac telethonin as an interaction partner for the protein kinase D catalytic domain. In this study, kinase assays used in conjunction with MS and site-directed mutagenesis confirmed telethonin as a substrate for protein kinase D and Ca(2+)/calmodulin-dependent kinase II in vitro and identified Ser-157 and Ser-161 as the phosphorylation sites. Phosphate affinity electrophoresis and MS revealed endogenous telethonin to exist in a constitutively bis-phosphorylated form in isolated adult rat ventricular myocytes and in mouse and rat ventricular myocardium. Following heterologous expression in myocytes by adenoviral gene transfer, wild-type telethonin became bis-phosphorylated, whereas S157A/S161A telethonin remained non-phosphorylated. Nevertheless, both proteins localized predominantly to the sarcomeric Z-disc, where they partially replaced endogenous telethonin. Such partial replacement with S157A/S161A telethonin disrupted transverse tubule organization and prolonged the time to peak of the intracellular Ca(2+) transient and increased its variance. These data reveal, for the first time, that cardiac telethonin is constitutively bis-phosphorylated and suggest that such phosphorylation is critical for normal telethonin function, which may include maintenance of transverse tubule organization and intracellular Ca(2+) transients.
KW - Amino Acid Substitution
KW - Animals
KW - Calcium
KW - Calcium-Calmodulin-Dependent Protein Kinase Type 2
KW - Cells, Cultured
KW - Connectin
KW - Heart Ventricles
KW - Humans
KW - Male
KW - Mice
KW - Microtubules
KW - Muscle Proteins
KW - Mutation, Missense
KW - Myocytes, Cardiac
KW - Phosphorylation
KW - Protein Kinase C
KW - Rats
KW - Rats, Wistar
KW - Sarcomeres
U2 - 10.1074/jbc.M113.479030
DO - 10.1074/jbc.M113.479030
M3 - SCORING: Journal article
C2 - 24280220
VL - 289
SP - 1282
EP - 1293
JO - J BIOL CHEM
JF - J BIOL CHEM
SN - 0021-9258
IS - 3
ER -