Publications

• Purification and properties of a kinase which phosphorylates and inactivates acetyl-CoA carboxylase.

  Lent B., Kim K.H.

  A protein kinase which phosphorylates and inactivates acetyl-CoA carboxylase has been purified to apparent homogeneity from rat liver. The kinase was found to exist in two forms: bound to carboxylase in a complex or in a free form that is in different stages of aggregation over a wide range of mol ... >> More

  A protein kinase which phosphorylates and inactivates acetyl-CoA carboxylase has been purified to apparent homogeneity from rat liver. The kinase was found to exist in two forms: bound to carboxylase in a complex or in a free form that is in different stages of aggregation over a wide range of molecular weights. The purification of the kinase involved first partial purification of acetyl-CoA carboxylase through polyethylene glycol precipitation and DEAE-cellulose chromatography. The kinase was then separated from acetyl-CoA carboxylase by Sepharose 2B chromatography. The molecular weight of the kinase subunit was 170,000 as determined by sodium dodecyl sulfate-gel electrophoresis. The incorporation of 1 mol of phosphate/mole of carboxylase subunit caused complete inactivation of the carboxylase. Acetyl-CoA carboxylase, inactivated by the kinase, can be dephosphorylated and reactivated when incubated with phosphorylase phosphatase. The Km values of the kinase for acetyl-CoA carboxylase and ATP are 90 nM and 20 microM, respectively. The kinase was found to be cyclic AMP-independent, but activated by CoA. The protein kinase can phosphorylate acetyl-CoA carboxylase, protamine, and histones, but could not act on hydroxymethylglutaryl-CoA reductase or phosphorylase b. << Less

  J Biol Chem 257:1897-1901(1982) [PubMed] [EuropePMC]

• Purification and characterisation of an insulin-stimulated protein-serine kinase which phosphorylates acetyl-CoA carboxylase.

  Heesom K.J., Moule S.K., Denton R.M.

  An insulin-stimulated protein kinase specific for acetyl-CoA carboxylase has been purified from rat epididymal adipose tissue using Mono-Q chromatography. The kinase binds to (and phosphorylates) the relatively inactive, dimeric form of acetyl-CoA carboxylase, but not to its active, polymeric form ... >> More

  An insulin-stimulated protein kinase specific for acetyl-CoA carboxylase has been purified from rat epididymal adipose tissue using Mono-Q chromatography. The kinase binds to (and phosphorylates) the relatively inactive, dimeric form of acetyl-CoA carboxylase, but not to its active, polymeric form, and this property has been used to purify the kinase. Under the conditions used, phosphorylation by the purified kinase did not result in a detectable increase in acetyl-CoA carboxylase activity. These studies also led to the recognition of an 'activator' protein which is capable of increasing the activity of acetyl-CoA carboxylase without changing its phosphorylation state. It is suggested that this 'activator' protein, together with the insulin-activated acetyl-CoA carboxylase kinase, may play a role in the activation of acetyl-CoA carboxylase by insulin. << Less

  FEBS Lett 422:43-46(1998) [PubMed] [EuropePMC]

• Phosphorylation of rat muscle acetyl-CoA carboxylase by AMP-activated protein kinase and protein kinase A.

  Winder W.W., Wilson H.A., Hardie D.G., Rasmussen B.B., Hutber C.A., Call G.B., Clayton R.D., Conley L.M., Yoon S., Zhou B.

  This study was designed to compare functional effects of phosphorylation of muscle acetyl-CoA carboxylase (ACC) by adenosine 3',5'-cyclic monophosphate-dependent protein kinase (PKA) and by AMP-activated protein kinase (AMPK). Muscle ACC (272 kDa) was phosphorylated and then subjected to sodium do ... >> More

  This study was designed to compare functional effects of phosphorylation of muscle acetyl-CoA carboxylase (ACC) by adenosine 3',5'-cyclic monophosphate-dependent protein kinase (PKA) and by AMP-activated protein kinase (AMPK). Muscle ACC (272 kDa) was phosphorylated and then subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by autoradiography. Functional effects of phosphorylation were determined by measuring ACC activity at different concentrations of each of the substrates and of citrate, an activator of the enzyme. The maximal velocity (Vmax) and the Michaelis constants (Km) for ATP, acetyl-CoA, and bicarbonate were unaffected by phosphorylation by PKA. Phosphorylation by AMPK increased the Km for ATP and acetyl-CoA. Sequential phosphorylation by PKA and AMPK, first without label and second with label, appeared to reduce the extent of label incorporation, regardless of the order. The activation constant (Ka) for citrate activation was increased to the same extent by AMPK phosphorylation, regardless of previous or subsequent phosphorylation by PKA. Thus muscle ACC can be phosphorylated by PKA but with no apparent functional effects on the enzyme. AMPK appears to be the more important regulator of muscle ACC. << Less

  J. Appl. Physiol. 82:219-225(1997) [PubMed] [EuropePMC]

• Isolation of three cyclic-AMP-independent acetyl-CoA carboxylase kinases from lactating rat mammary gland and characterization of their effects on enzyme activity.

  Munday M.R., Hardie D.G.

  Three cyclic AMP-independent acetyl-CoA carboxylase kinases (A, B1 and B2) have been isolated from lactating rat mammary gland, using phosphocellulose chromatography, high performance gel filtration, and affinity chromatography on casein-Sepharose and phosvitin-Sepharose. These protein kinases hav ... >> More

  Three cyclic AMP-independent acetyl-CoA carboxylase kinases (A, B1 and B2) have been isolated from lactating rat mammary gland, using phosphocellulose chromatography, high performance gel filtration, and affinity chromatography on casein-Sepharose and phosvitin-Sepharose. These protein kinases have been identified with previously described kinases by the following criteria. Kinase A phosphorylates the same sites on rabbit mammary acetyl-CoA carboxylase as acetyl-CoA carboxylase kinase 2, which was originally described as a contaminant of rabbit mammary acetyl-CoA carboxylase purified by the poly(ethylene glycol)procedure. Kinase A will henceforth be referred to as acetyl-CoA carboxylase kinase-2. Kinase B1 has been identified with casein kinase II by its heparin sensitivity, elution behaviour on phosphocellulose, molecular mass, substrate specificity and subunit composition. Kinase B2 has been identified with casein kinase I by its elution behaviour on phosphocellulose, molecular mass, substrate specificity and subunit composition. The three kinases phosphorylate distinct sites on acetyl-CoA carboxylase. Phosphorylation by either casein kinase I or II does not affect enzyme activity. However, acetyl-CoA carboxylase kinase 2 inactivates acetyl-CoA carboxylase reversibly, in an identical manner to cyclic-AMP-dependent protein kinase, and phosphorylates sites located on identical peptides. Acetyl-CoA carboxylase kinase-2 can, however, be distinguished from the free catalytic subunit of cyclic-AMP-dependent protein kinase by its molecular mass, its substrate specificity, its elution behaviour on phosphocellulose, and its complete lack of sensitivity to the protein inhibitor of cyclic-AMP-dependent protein kinase. We also present evidence that phosphorylation of acetyl-CoA carboxylase by cyclic-AMP-dependent protein kinase occurs directly and not via a bicyclic cascade system as proposed by other laboratories. << Less

  Eur J Biochem 141:617-627(1984) [PubMed] [EuropePMC]