The control of protein phosphatase-1 by targetting subunits. The major myosin phosphatase in avian smooth muscle is a novel form of protein phosphatase-1.

The major protein phosphatase that dephosphorylates smooth-muscle myosin was purified from chicken gizzard myofibrils and shown to be composed of three subunits with apparent molecular masses of 130, 37 and 20 kDa, the most likely structure being a heterotrimer. The 37-kDa component was the catalytic subunit, while the 130-kDa and 20-kDa components formed a regulatory complex that enhanced catalytic subunit activity towards heavy meromyosin or the isolated myosin P light chain from smooth muscle and suppressed its activity towards phosphorylase, phosphorylase kinase and glycogen synthase. The catalytic subunit was identified as the beta isoform of protein phosphatase-1 (PP1) and the 130-kDa subunit as the PP1-binding component. The distinctive properties of smooth and skeletal muscle myosin phosphatases are explained by interaction of PP1 beta with different proteins and (in conjunction with earlier analysis of the glycogen-associated phosphatase) establish that the specificity and subcellular location of PP1 is determined by its interaction with a number of specific targetting subunits.

[1]  E. F. da Cruz e Silva,et al.  Drosophila contains three genes that encode distinct isoforms of protein phosphatase 1. , 1990, European journal of biochemistry.

[2]  P. Cohen,et al.  Protein phosphatases: properties and role in cellular regulation. , 1983, Science.

[3]  P. Cohen,et al.  Protein phosphatase 1 activity in Drosophila mutants with abnormalities in mitosis and chromosome condensation , 1990, FEBS letters.

[4]  P. Cohen,et al.  The molecular mechanism by which adrenalin inhibits glycogen synthesis. , 1991, European journal of biochemistry.

[5]  W. Stalmans,et al.  The inhibitory effect of phosphorylase a on the activation of glycogen synthase depends on the type of synthase phosphatase. , 1983, The Biochemical journal.

[6]  U. K. Laemmli,et al.  Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4 , 1970, Nature.

[7]  R. Adelstein,et al.  Purification and characterization of a multisubunit phosphatase from turkey gizzard smooth muscle. The effect of calmodulin binding to myosin light chain kinase on dephosphorylation. , 1983, The Journal of biological chemistry.

[8]  T. Toda,et al.  The fission yeast dis2 + gene required for chromosome disjoining encodes one of two putative type 1 protein phosphatases , 1989, Cell.

[9]  R. Adelstein,et al.  Characterization of a Mg2+-dependent phosphatase from turkey gizzard smooth muscle. , 1983, The Journal of biological chemistry.

[10]  P. Cohen,et al.  Further studies on the structure of the glycogen-bound form of protein phosphatase-1 from rabbit skeletal muscle. , 1987, European journal of biochemistry.

[11]  P. Cohen,et al.  Regulation of protein phosphatase-1G from rabbit skeletal muscle. 2. Catalytic subunit translocation is a mechanism for reversible inhibition of activity toward glycogen-bound substrates. , 1989, European journal of biochemistry.

[12]  P. Cohen.  The structure and regulation of protein phosphatases. , 1989, Annual review of biochemistry.

[13]  K. J. Monty,et al.  Determination of molecular weights and frictional ratios of proteins in impure systems by use of gel filtration and density gradient centrifugation. Application to crude preparations of sulfite and hydroxylamine reductases. , 1966, Biochimica et biophysica acta.

[14]  E. Krebs,et al.  The isolation and crystallization of rabbit skeletal muscle phosphorylase b. , 1958, The Journal of biological chemistry.

[15]  P. Cohen,et al.  The MgATP-dependent protein phosphatase and protein phosphatase 1 have identical substrate specificities. , 2005, European journal of biochemistry.

[16]  E. Carafoli,et al.  Nature and site of phospholamban regulation of the Ca2+ pump of sarcoplasmic reticulum , 1989, Nature.

[17]  S. Lowey,et al.  [7] Preparation of myosin and its subfragments from rabbit skeletal muscle , 1982 .

[18]  P. Cohen,et al.  The protein phosphatases involved in cellular regulation. Evidence that dephosphorylation of glycogen phosphorylase and glycogen synthase in the glycogen and microsomal fractions of rat liver are catalysed by the same enzyme: protein phosphatase-1. , 1986, European journal of biochemistry.

[19]  P. Cohen,et al.  Targetting of protein phosphatase 1 to the sarcoplasmic reticulum of rabbit skeletal muscle by a protein that is very similar or identical to the G subunit that directs the enzyme to glycogen. , 1990, European journal of biochemistry.

[20]  D. Blumenthal,et al.  Activation of skeletal muscle myosin light chain kinase by calcium(2+) and calmodulin. , 1980, Biochemistry.

[21]  T. Hunter,et al.  Detection and quantification of phosphotyrosine in proteins. , 1983, Methods in enzymology.

[22]  M. Yanagida,et al.  S. pombe gene sds22 + essential for a midmitotic transition encodes a leucine-rich repeat protein that positively modulates protein phosphatase-1 , 1991, Cell.

[23]  P. Cohen,et al.  Phosphorylase a is an allosteric inhibitor of the glycogen and microsomal forms of rat hepatic protein phosphatase‐1 , 1986, FEBS letters.

[24]  D. Bregman,et al.  Molecular characterization of bovine brain P75, a high affinity binding protein for the regulatory subunit of cAMP-dependent protein kinase II beta. , 1991, The Journal of biological chemistry.

[25]  A. Means,et al.  Proteolysis of smooth muscle myosin light chain kinase. Formation of inactive and calmodulin-independent fragments. , 1987, The Journal of biological chemistry.

[26]  P. Cohen,et al.  An improved procedure for identifying and quantitating protein phosphatases in mammalian tissues , 1989, FEBS letters.

[27]  H. Towbin,et al.  Electrophoretic transfer of proteins from polyacrylamide gels to nitrocellulose sheets: procedure and some applications. , 1979, Proceedings of the National Academy of Sciences of the United States of America.

[28]  Philip R. Cohen,et al.  Cyanobacterial microcystin‐LR is a potent and specific inhibitor of protein phosphatases 1 and 2A from both mammals and higher plants , 1990, FEBS letters.

[29]  P. Dent,et al.  The molecular mechanism by which insulin stimulates glycogen synthesis in mammalian skeletal muscle , 1990, Nature.

[30]  P. Cohen,et al.  A myofibrillar protein phosphatase from rabbit skeletal muscle contains the beta isoform of protein phosphatase-1 complexed to a regulatory subunit which greatly enhances the dephosphorylation of myosin. , 1992, European journal of biochemistry.

[31]  P. Cohen,et al.  Okadaic acid: a new probe for the study of cellular regulation. , 1990, Trends in biochemical sciences.

[32]  P. Cohen,et al.  The subunit structure of rabbit-skeletal-muscle phosphorylase kinase, and the molecular basis of its activation reactions. , 1973, European journal of biochemistry.

[33]  P. Wagner.  Preparation and fractionation of myosin light chains and exchange of the essential light chains. , 1982, Methods in enzymology.

[34]  M. Tada,et al.  Regulation of the Ca2+ pump atpase by cAMP‐dependent phosphorylation of phospholamban , 1989, BioEssays : news and reviews in molecular, cellular and developmental biology.

[35]  D. Glover,et al.  One of the protein phosphatase 1 isoenzymes in Drosophila is essential for mitosis , 1990, Cell.

[36]  P. Cohen,et al.  The glycogen-binding subunit of protein phosphatase-1G from rabbit skeletal muscle. Further characterisation of its structure and glycogen-binding properties. , 1989, European journal of biochemistry.

[37]  P. Cohen,et al.  Regulation of protein phosphatase-1G from rabbit skeletal muscle. 1. Phosphorylation by cAMP-dependent protein kinase at site 2 releases catalytic subunit from the glycogen-bound holoenzyme. , 1989, European journal of biochemistry.

[38]  E. Reimann,et al.  [6] Catalytic subunit of cAMP-dependent protein kinase , 1983 .

[39]  W. Stalmans,et al.  The role of the liver in the homeostasis of blood glucose. , 1976, Current topics in cellular regulation.

[40]  P. Cohen,et al.  Distinct type-1 protein phosphatases are associated with hepatic glycogen and microsomes. , 1988, Biochimica et biophysica acta.

[41]  P. Cohen.  Classification of protein-serine/threonine phosphatases: identification and quantitation in cell extracts. , 1991, Methods in enzymology.

[42]  Y. You,et al.  Cloning and expression of an intron-less gene for AKAP 75, an anchor protein for the regulatory subunit of cAMP-dependent protein kinase II beta. , 1992, The Journal of biological chemistry.

[43]  P. Cohen,et al.  Protein phosphatase inhibitor-1 and inhibitor-2 from rabbit skeletal muscle. , 1988, Methods in enzymology.

[44]  P. Cohen,et al.  Isolation and sequence analysis of a cDNA clone encoding a type‐1 protein phosphatase catalytic subunit: Homology with protein phosphatase 2A , 1987, FEBS letters.

[45]  A. Depaoli-Roach,et al.  Molecular cloning and expression of the regulatory (RG1) subunit of the glycogen-associated protein phosphatase. , 1991, The Journal of biological chemistry.

[46]  P. Cohen,et al.  The protein phosphatases involved in cellular regulation. Purification and characterisation of the glycogen-bound form of protein phosphatase-1 from rabbit skeletal muscle. , 1985, European journal of biochemistry.

[47]  H. Tung,et al.  Protein phosphatase-1 and protein phosphatase-2A from rabbit skeletal muscle. , 1988, Methods in enzymology.

[48]  Anne Fernandez,et al.  Cyclin a is required for the onset of DNA replication in mammalian fibroblasts , 1991, Cell.

[49]  D. Hartshorne,et al.  Proteolysis of smooth muscle myosin by Staphylococcus aureus protease: preparation of heavy meromyosin and subfragment 1 with intact 20 000-dalton light chains. , 1985, Biochemistry.

[50]  Mary,et al.  Turkey gizzard smooth muscle myosin phosphatase-III is a novel protein phosphatase. , 1991, The Journal of biological chemistry.

[51]  P. Cohen,et al.  The protein phosphatases involved in cellular regulation. 4. Classification of two homogeneous myosin light chain phosphatases from smooth muscle as protein phosphatase-2A1 and 2C, and a homogeneous protein phosphatase from reticulocytes active on protein synthesis initiation factor eIF-2 as protein , 1983, European journal of biochemistry.

[52]  P. Cohen,et al.  Arachidonic acid inhibits myosin light chain phosphatase and sensitizes smooth muscle to calcium. , 1992, The Journal of biological chemistry.

[53]  P. Cohen.  Two isoforms of protein phosphatase 1 may be produced from the same gene , 1988, FEBS letters.

[54]  M. M. Bradford.  A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. , 1976, Analytical biochemistry.

[55]  H. Tung,et al.  The catalytic subunits of protein phosphatase-1 and protein phosphatase 2A are distinct gene products. , 1984, European journal of biochemistry.

[56]  P. Cohen,et al.  Identification of the major protein phosphatases in mammalian cardiac muscle which dephosphorylate phospholamban. , 1991, European journal of biochemistry.

[57]  T. Sugimura,et al.  Identification of Members of the Protein Phosphatase 1 Gene Family in the Rat and Enhanced Expression of Protein Phosphatase 1α Gene in Rat Hepatocellular Carcinomas , 1990, Japanese journal of cancer research : Gann.

[58]  P. Cohen,et al.  The purification and properties of rabbit skeletal muscle glycogen synthase. , 1976, European journal of biochemistry.

[59]  M. Pato,et al.  Purification and characterization of a smooth muscle myosin phosphatase from turkey gizzards. , 1985, The Journal of biological chemistry.

[60]  P. Cohen,et al.  Protein phosphatase-2B from rabbit skeletal muscle: a Ca2+-dependent, calmodulin-stimulated enzyme. , 1988, Methods in enzymology.

[61]  Toshio Kitazawa,et al.  G-protein-mediated Ca2+ sensitization of smooth muscle contraction through myosin light chain phosphorylation. , 1991, The Journal of biological chemistry.

[62]  J. Doonan,et al.  The bimG gene of Aspergillus nidulans, required for completion of anaphase, encodes a homolog of mammalian phosphoprotein phosphatase 1 , 1989, Cell.