scholarly journals The Hormonal Control of Activity of Skeletal Muscle Phosphorylase Kinase. Amino-Acid Sequences at the Two Sites of Action of Adenosine-3': 5'-Monophosphate-Dependent Protein Kinase

1975 ◽  
Vol 51 (1) ◽  
pp. 79-92 ◽  
Author(s):  
Philip COHEN ◽  
David C. WATSON ◽  
Gordon H. DIXON

1977 ◽  
Vol 162 (2) ◽  
pp. 411-421 ◽  
Author(s):  
S J Yeaman ◽  
P Cohen ◽  
D C Watson ◽  
G H Dixon

The known amino acid sequences at the two sites on phosphorylase kinase that are phosphorylated by cyclic AMP-dependent protein kinase were extended. The sequences of 42 amino acids around the phosphorylation site on the alpha-subunit and of 14 amino acids around the phosphorylation site on the beta-subunit were shown to be: alpha-subunit Phe-Arg-Arg-Leu-Ser(P)-Ile-Ser-Thr-Glu-Ser-Glx-Pro-Asx-Gly-Gly-His-Ser-Leu-Gly-Ala-Asp-Leu-Met-Ser-Pro-Ser-Phe-Leu-Ser-Pro-Gly-Thr-Ser-Val-Phe(Ser,Pro,Gly)His-Thr-Ser-Lys; beta-subunit, Ala-Arg-Thr-Lys-Arg-Ser-Gly-Ser(P)-VALIle-Tyr-Glu-Pro-Leu-Lys. The sites on histone H2B which are phosphorylated by cyclic AMP-dependent protein kinase in vitro were identified as serine-36 and serine-32. The amino acid sequence in this region is: Lys-Lys-Arg-Lys-Arg-Ser32(P)-Arg-Lys-Glu-Ser36(P)-Tyr-Ser-Val-Tyr-Val- [Iwai, K., Ishikawa, K. & Hayashi, H. (1970) Nature (London) 226, 1056-1058]. Serine-36 was phosphorylated at 50% of the rate at which the beta-subunit of phosphorylase kinase was phosphorylated, and it was phosphorylated 6-7-fold more rapidly than was serine-32. The amino acid sequences when compared with those at the phosphorylation sites of other physiological substrates suggest that the presence of two adjacent basic amino acids on the N-terminal side of the susceptible serine residue may be critical for specific substrate recognition in vivo.



1975 ◽  
Vol 149 (3) ◽  
pp. 525-533 ◽  
Author(s):  
H A Cole ◽  
S V Perry

1. Troponin I isolated from fresh cardiac muscle by affinity chromatography contains about 1.9 mol of covalently bound phosphate/mol. Similar preparations of white-skeletal-muscle troponin I contain about 0.5 mol of phosphate/mol. 2. A 3':5'-cyclic AMP-dependent protein kinase and a protein phosphatase are associated with troponin isolated from cardiac muscle. 3. Bovine cardiac 3':5'-cyclic AMP-dependent protein kinase catalyses the phosphorylation of cardiac troponin I 30 times faster than white-skeletal-muscle troponin I. 4. Troponin I is the only component of cardiac troponin phosphorylated at a significant rate by the endogenous or a bovine cardiac 3':5'-cyclic AMP-dependent protein kinase. 5. Phosphorylase kinase catalyses the phosphorylation of cardiac troponin I at similar or slightly faster rates than white-skeletal-muscle troponin I. 6. Troponin C inhibits the phosphorylation of cardiac and skeletal troponin I catalysed by phosphorylase kinase and the phosphorylation of white skeletal troponin I catalysed by 3':5'-cyclic AMP-dependent protein kinase; the phosphorylation of cardiac troponin I catalysed by the latter enzyme is not inhibited.



1993 ◽  
Vol 71 (11-12) ◽  
pp. 501-506 ◽  
Author(s):  
Hussein Mehrani ◽  
Kenneth B. Storey

To analyze the mechanisms of glycogen phosphorylase control in organs of the rainbow trout Oncorhynchus mykiss, activities of glycogen phosphorylase kinase (GPK) and cAMP-dependent protein kinase (PKA), as well as levels of cAMP, were quantified. The complete cascade for activating glycogen phosphorylase was present in trout organs and all components were activated in white skeletal muscle and liver during exhaustive swimming exercise. GPK and PKA showed the highest activities in the liver, being three- and four-fold higher than corresponding activities in white muscle. Exercise stimulated a 60% increase in GPK activity in the liver and a 40% rise in white muscle. Furthermore, the amount of active PKA rose from 12 to 21% in the liver and from 32 to 57% in white muscle after exhaustive exercise and the cellular levels of cAMP increased by 50% in the liver and 70% in white muscle of exercised fish. Other organs (heart, gill, brain, kidney) showed little or no change in these parameters as a result of exhaustive exercise. GPK activity in liver, muscle, and heart extracts was strongly stimulated by in vitro incubation with the catalytic subunit of mammalian PKA, activity rising by 6- to 7-fold in white muscle extracts and 2- to 2.6-fold in liver and heart extracts. This occurred in extracts from both control and exercised fish and suggested that even in fish exercised to exhaustion, the maximal enzymatic potential for activation of glycogenolysis was not expressed. Other modes of GPK activation were not apparent, for the enzyme in crude extracts was stimulated only by incubation with cAMP and did not respond to cGMP or Ca2+ + phorbol 12-myristate 13-acetate. The data indicate that the cAMP-activated, PKA- and GPK-mediated cascade is key to the activation of glycogenolysis in both the skeletal muscle and liver during burst swimming exercise by trout.Key words: exercise, glycogen phosphorylase kinase, protein kinase A, cAMP, Oncorhynchus mykiss, control of glycogenolysis.



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