Protein phosphatase 2A1 was purified from rat skeletal muscle and used to produce antisera to the three subunits of the holoenzyme. Affinity purified antibodies specific for the subunits of the phosphatase enzyme were found to recognize the type 2A1 and 2A2 phosphatase from rat skeletal muscle, heart, liver, brain and erythrocytes and were used to investigate the effects of diabetes on the levels of this enzyme in liver and heart. Phosphorylase phosphatase assays coupled with immunoblot analysis of fractionated rat liver and heart cytosol from normal and diabetic animals show no apparent differences in the quantity or activity of these enzymes following the induction of alloxan diabetes. When considering these results and the normal physiological concentrations of known effectors of these enzymes, it is likely that protein phosphatase 2A1 and 2A2 are not responsible for the dephosphorylation of phosphorylase a under physiological conditions.
This is a preview of subscription content, log in to check access.
Buy single article
Instant access to the full article PDF.
Price includes VAT for USA
Subscribe to journal
Immediate online access to all issues from 2019. Subscription will auto renew annually.
This is the net price. Taxes to be calculated in checkout.
Edelman AM, Blumenthal DK, Krebs EG: Protein scrinethreonine kinases. Ann Rev Biochem 56: 576–613, 1987
Hunter T, Cooper JA: Protein-tyrosine kinases. Ann Rev Biochem 54: 897–930, 1985
Cohen P: The structure and regulation of protein phosphatases. Ann Rev Biochem 58: 453–508, 1989
Pato MD, Adelstein RS: Dephosphorylation of the 20,000 dalton light chain of myosin by two different phosphatases from smooth muscle. J Biol Chem 255: 6535–6538, 1980
Mumby MC, Russell KL, Garrard LJ, Green DD: Cardiac contractile protein phosphatases: purification of two enzyme forms and their characterization with subunit specific antibodies. J Biol Chem 262: 6257–6265, 1987
Gilboe DP, Larsen KL, Nuttall FQ: Radioactive method for assay of glycogen phosphorylase. Anal Biochem 47: 20–27, 1972
Rulfs J, Jaspers SR, Garnache AK, Miller TB: Phosphorylase synthesis in diabetic hepatocytes and cardiomyocytes. Am J Physiol 257: E74-E80, 1989
Tung HYL, Alemany S, Cohen P: The protein phosphatases involved with cellular regulation. 2. purification, subunit structure and properties of protein phosphatases 2A0, 2A1, and 2A2 from rabbit skeletal muscle. Eur J Biochem 148: 253–263, 1985
Usui H, Imazu M, Maeta K, Tsukamoto H, Azuma K, Takeda M: Three distinct forms of type 2A protein phosphatase in human erythrocyte cytosol. J Biol Chem 263: 3752–3761, 1988
Ingebritsen TS, Stewart AA, Cohen P: The protein phosphatases involved in cellular regulation 6. measurement of type 1 and type 2 protein phosphatases in extracts of mam malian tissues; an assessment of their physiological roles. Eur J Biochem 132: 297–307, 1983
Csortos C, Farkas I, Sparks L, Banyasz T, Kovacs T, Gergely P: Phosphorylase phosphatase activities of rat liver in streptozotocin-diabetes. Biochim Biophys Acta 1052: 235–241, 1990
Foulkes JG, Jefferson LS: Protein phosphatase-1 and -2A activities in heart, liver and skeletal muscle extracts from control and diabetic rats. Diabetes 33: 576–579, 1984
Parsadanian HK, Ter-Tatevosian LP, Martikian HR, Avakian SH: Changes in the activity of enzymes, participating in glycogen metabolism of alloxan diabetic rats. Mol Cell Biochem 90: 185–190, 1989
Goris J, Pallen CJ, Parker PJ, Hermann J, Waterfield MD, Merlevede W: Conversion of phosphoseryl/threonyl phosphatase into a phosphotyrosine phosphatase. Biochem J 256: 1029–1034, 1988
Ingebritsen TS, Foulkes JG, Cohen P: The broad specificity protein phosphatase from mammalian liver. FEBS Lett 119: 9–15, 1980
Khandelwal RL, Enno TL: Purification and characterization of a high molecular weight phosphoprotein phosphatase from rabbit liver. J Biol Chem 260: 14335–14343, 1985
DeGuzman A, Lee EYC: Preparation of low-molecular weight forms of rabbit muscle protein phosphatase. Meth Enzymol 159: 356–368, 1988
Crouch D, Safer B: Purification and properties of elF 2 phosphatase. J Biol Chem 255: 7918–7924, 1980
Sturgill TW, Ray LB, Erickson E, Maller JL: Insulin-stimulated MAP-2 kinase phosphorylates and activates ribosomal protein S6 kinase II. Nature 334: 715–718, 1988
Kozma SC, Lane HA, Ferrari S, Luther H, Siegmann M, Thomas G: A stimulated S6 kinase from rat liver: identity with the mitogen activated S6 kinase of 3T3 cells. EMBO J 8: 4125–4132, 1989
Gregory JS, Boulton TG, Sang B-C, Cobb MH: An insulin stimulated ribosomal S6 kinase from rabbit liver. J Biol Chem 264: 18397–18401, 1989
Virshup DM, Kauffmann MG, Kelly TJ: Activation of SV 40 DNA replication in vitro by cellular protein phosphatase 2A. EMBO J 8: 3891–3898, 1989
Pallas DC, Shahrik LK, Martin BL, Jaspers S, Miller TB, Brautigan DL, Roberts TM: Polyoma small and middle T antigens and SV 40 small t antigen form stable complexes with protein phosphatase 2A. Cell 60: 167–176, 1990
About this article
Cite this article
Jaspers, S.R., Miller, T.B. Purification and the immunological characterization of rat protein phosphatase 2A: enzyme levels in diabetic liver and heart. Mol Cell Biochem 101, 167–174 (1991). https://doi.org/10.1007/BF00229533
- rat protein phosphatase 2A