The Regulation of Ca 2 ' Transport by Fast Skeletal Muscle Sarcoplasmic Reticulum
نویسنده
چکیده
Ca2+ uptake and Ca2+-dependent ATP hydrolysis of fast skeletal muscle sarcoplasmic reticulum (SR) are strongly inhibited by trifluoperazine ('I"). Inhibition, which is Ca2+-dependent, is 90% with 14 p~ TFP and 0.2 p~ Ca2+. TFP interacts strongly, in a Ca2+-dependent way, with two SR proteins, calmodulin and the 53,000dalton glycoprotein. The two proteins were purified by TFP affinity chromatography. The inhibition of SR activity by TFP was correlated with the interaction of the drug with the glycoprotein, rather than with calmodulin. The main effect was a shift of the (Ca2'-M&')ATPase from a high to a low affinity form. Calmodulin-dependent phosphorylation of three proteins (M, = 57,000, 35,000, and 20,000) of the SR membrane of fast skeletal muscle was also demonstrated. Phosphorylation of these three proteins plays no role in the regulation of the active Caz+-uptake reaction.
منابع مشابه
Rapid communication: mapping of the Ca2+ ATPase of fast twitch 1 skeletal muscle sarcoplasmic reticulum (ATP2A1) gene to porcine chromosome 3.
Rapid communication: Mapping of the Ca 2+ ATPase of fast twitch 1 skeletal muscle sarcoplasmic reticulum (ATP2A1) gene to porcine chromosome 3" (2002).
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