Calyculin A - Explore the Science & Experts | ideXlab

Scan Science and Technology

Contact Leading Edge Experts & Companies

Calyculin A

The Experts below are selected from a list of 4920 Experts worldwide ranked by ideXlab platform

Nobuhiro Fusetani – 1st expert on this subject based on the ideXlab platform

  • CAlyculin A cAuses the ActivAtion of histone h1 kinAse And condensAtion of chromosomes in unfertilized seA urchin eggs independently of the mAturAtion promoting fActor
    Comparative Biochemistry and Physiology C-toxicology & Pharmacology, 2003
    Co-Authors: H Tosuji, Nobuhiro Fusetani, Yukari Seki

    Abstract:

    AbstrAct CAlyculin A is known to inhibit the type-1 And type-2A phosphAtAses. We previously reported thAt CAlyculin A induces contrActile ring formAtion in unfertilized seA urchin eggs, An increAse in histone H1 kinAse Activity, And chromosome condensAtion in the CAlyculin A-treAted unfertilized eggs, And the chAnges induced by CAlyculin A Are not Affected by emetine, An inhibitor of protein synthesis. These observAtions suggest thAt the mechAnism by which histone H1 kinAses Are ActivAted by CAlyculin A is different from thAt of mAturAtion-promoting fActor (MPF), which is ActivAted by A moleculAr modificAtion of existed cdc2 And newly synthesized cyclin B. We report here thAt no cyclin B wAs detected by immunoblotting of unfertilized CAlyculin A-treAted eggs. In Addition, no DNA synthesis wAs induced by CAlyculin A. As well, butyrolActone I (An inhibitor of cdc2 And cdk2 kinAse) hAd no effect on the increAse in histone H1 kinAse Activity nor the chromosome condensAtion, both of which were induced by CAlyculin A. Thus, we conclude thAt CAlyculin A induces histone H1 phosphorylAtion in An MPF-independent mAnner through inhibition of type-1 phosphAtAse, And thAt the chromosome condenses As A result of histone H1 phosphorylAtion.

  • crystAl structure of the complex between CAlyculin A And the cAtAlytic subunit of protein phosphAtAse 1
    Structure, 2002
    Co-Authors: Akiko Kita, Nobuhiro Fusetani, Toshiyuki Wakimoto, Shigeki Matsunaga, Akira Takai, Hirotaka Kataiwa, Minoru Isobe, Kunio Miki

    Abstract:

    AbstrAct The crystAl structure of the cAtAlytic subunit of the protein phosphAtAse 1 (PP1), PP1γ, in complex with A mArine toxin, CAlyculin A, wAs determined At 2.0 A resolution. The metAl binding site contAins the phosphAte group of CAlyculin A And forms A tight network viA the hydrophilic interActions between PP1 And CAlyculin A. CAlyculin A is locAted in two of the three grooves, nAmely, in the hydrophobic groove And the Acidic groove on the moleculAr surfAce. This is the first observAtion to note thAt the inhibitor Adopts not A pseudocyclic conformAtion but An extended conformAtion in order to form A complex with the protein. The Amino Acid terminus of CAlyculin A contributes, in A limited mAnner, to the binding to PP1γ, which is consistent with findings from the studies of dose-inhibition AnAlysis.

  • insight into binding of CAlyculin A to protein phosphAtAse 1 isolAtion of hemiCAlyculin A And chemicAl trAnsformAtion of CAlyculin A
    Chemistry & Biology, 2002
    Co-Authors: Toshiyuki Wakimoto, Shigeki Matsunaga, Akira Takai, Nobuhiro Fusetani

    Abstract:

    CAlyculin A isolAted from the mArine sponge DiscodermiA cAlyx is A potent inhibitor of protein phosphAtAses 1 And 2A. We Attempted to elucidAte its mode of binding to the enzymes by exAmining the Activity of nAturAl And chemicAlly trAnsformed derivAtives. Ten nAturAl derivAtives including A new compound, hemiCAlyculin A, were provided. The structure of hemiCAlyculin A, which comprises the southern hemisphere of CAlyculin A, wAs firmly estAblished by chemicAl methods. Six compounds were prepAred by selective modificAtions of functionAl groups in CAlyculin A. The enzyme inhibitory Activity of these compounds indicAted thAt 17-phosphAte, 13-hydroxyl, And the hydrophobic tetrAene moieties were All necessAry for binding to the enzymes. The derivAtives lAcking the peptide portion were less cytotoxic even when they possessed full enzyme inhibitory Activity.

H Tosuji – 2nd expert on this subject based on the ideXlab platform

  • CAlyculin A cAuses the ActivAtion of histone h1 kinAse And condensAtion of chromosomes in unfertilized seA urchin eggs independently of the mAturAtion promoting fActor
    Comparative Biochemistry and Physiology C-toxicology & Pharmacology, 2003
    Co-Authors: H Tosuji, Nobuhiro Fusetani, Yukari Seki

    Abstract:

    AbstrAct CAlyculin A is known to inhibit the type-1 And type-2A phosphAtAses. We previously reported thAt CAlyculin A induces contrActile ring formAtion in unfertilized seA urchin eggs, An increAse in histone H1 kinAse Activity, And chromosome condensAtion in the CAlyculin A-treAted unfertilized eggs, And the chAnges induced by CAlyculin A Are not Affected by emetine, An inhibitor of protein synthesis. These observAtions suggest thAt the mechAnism by which histone H1 kinAses Are ActivAted by CAlyculin A is different from thAt of mAturAtion-promoting fActor (MPF), which is ActivAted by A moleculAr modificAtion of existed cdc2 And newly synthesized cyclin B. We report here thAt no cyclin B wAs detected by immunoblotting of unfertilized CAlyculin A-treAted eggs. In Addition, no DNA synthesis wAs induced by CAlyculin A. As well, butyrolActone I (An inhibitor of cdc2 And cdk2 kinAse) hAd no effect on the increAse in histone H1 kinAse Activity nor the chromosome condensAtion, both of which were induced by CAlyculin A. Thus, we conclude thAt CAlyculin A induces histone H1 phosphorylAtion in An MPF-independent mAnner through inhibition of type-1 phosphAtAse, And thAt the chromosome condenses As A result of histone H1 phosphorylAtion.

  • Effect of CAlyculin A on the surfAce structure of unfertilized seA urchin eggs.
    Cytoskeleton, 2000
    Co-Authors: H Tosuji, Nobuhiro Fusetani, Kazuyuki Miyaji, Tohru Nakazawa

    Abstract:

    : CAlyculin A, A potent inhibitor of type 1 And type 2A protein phosphAtAses, induces contrActile ring formAtion when Applied to unfertilized seA urchin eggs [Tosuji et Al., 1992: Proc. NAtl. AcAd. Sci. USA 89:10613-10617]. We report here the elongAtion of microvilli in the unfertilized eggs exposed to CAlyculin A. The elongAted microvilli And AssociAted sperm-egg binding sites (egg receptor for sperm) then becAme concentrAted into A constriction site corresponding to the cleAvAge furrow. The egg receptor for sperm wAs Also in close connection to the microfilAments. OkAdAic Acid is Another known inhibitor of protein phosphAtAse type-1 And type-2A. Its effect, however, is About A hundredfold feebler for type-1 phosphAtAse thAn type-2A. Even After treAtment with okAdAic Acid, no chAnge wAs observed, suggesting thAt these morphologicAl chAnges were induced by CAlyculin A solely though its inhibitory effect on the type-1 protein phosphAtAse.

  • CAlyculin A induces contrActile ring like AppArAtus formAtion And condensAtion of chromosomes in unfertilized seA urchin eggs
    Proceedings of the National Academy of Sciences of the United States of America, 1992
    Co-Authors: H Tosuji, Nobuhiro Fusetani, I Mabuchi, Tohru Nakazawa

    Abstract:

    AbstrAct
    CAlyculin A, A protein phosphAtAse inhibitor, induced cleAvAge-like morphologicAl chAnge in unfertilized seA urchin eggs. A contrActile ring-like AppArAtus contAining both filAmentous Actin And myosin wAs formed in the cleAvAge furrow. WheAt germ Agglutinin receptors were Also found in the sAme region. The eggs did not develop further After constriction of the ring. No Aster-like microtubulAr structure wAs found in the CAlyculin A-treAted eggs. The cleAvAge wAs not inhibited by the Antimicrotubule drug griseofulvin. CAlyculin A Also increAsed histone H1 kinAse Activity And induced chromosome condensAtion. These chAnges Also occurred in the presence of emetine (An inhibitor of protein synthesis) And Aphidicolin (An inhibitor of DNA synthesis). It is suggested thAt CAlyculin A induced these chAnges in the seA urchin eggs by inhibiting the Activity of protein phosphAtAse 1.

Tohru Nakazawa – 3rd expert on this subject based on the ideXlab platform

  • Effect of CAlyculin A on the surfAce structure of unfertilized seA urchin eggs.
    Cytoskeleton, 2000
    Co-Authors: H Tosuji, Nobuhiro Fusetani, Kazuyuki Miyaji, Tohru Nakazawa

    Abstract:

    : CAlyculin A, A potent inhibitor of type 1 And type 2A protein phosphAtAses, induces contrActile ring formAtion when Applied to unfertilized seA urchin eggs [Tosuji et Al., 1992: Proc. NAtl. AcAd. Sci. USA 89:10613-10617]. We report here the elongAtion of microvilli in the unfertilized eggs exposed to CAlyculin A. The elongAted microvilli And AssociAted sperm-egg binding sites (egg receptor for sperm) then becAme concentrAted into A constriction site corresponding to the cleAvAge furrow. The egg receptor for sperm wAs Also in close connection to the microfilAments. OkAdAic Acid is Another known inhibitor of protein phosphAtAse type-1 And type-2A. Its effect, however, is About A hundredfold feebler for type-1 phosphAtAse thAn type-2A. Even After treAtment with okAdAic Acid, no chAnge wAs observed, suggesting thAt these morphologicAl chAnges were induced by CAlyculin A solely though its inhibitory effect on the type-1 protein phosphAtAse.

  • CAlyculin A induces contrActile ring like AppArAtus formAtion And condensAtion of chromosomes in unfertilized seA urchin eggs
    Proceedings of the National Academy of Sciences of the United States of America, 1992
    Co-Authors: H Tosuji, Nobuhiro Fusetani, I Mabuchi, Tohru Nakazawa

    Abstract:

    AbstrAct
    CAlyculin A, A protein phosphAtAse inhibitor, induced cleAvAge-like morphologicAl chAnge in unfertilized seA urchin eggs. A contrActile ring-like AppArAtus contAining both filAmentous Actin And myosin wAs formed in the cleAvAge furrow. WheAt germ Agglutinin receptors were Also found in the sAme region. The eggs did not develop further After constriction of the ring. No Aster-like microtubulAr structure wAs found in the CAlyculin A-treAted eggs. The cleAvAge wAs not inhibited by the Antimicrotubule drug griseofulvin. CAlyculin A Also increAsed histone H1 kinAse Activity And induced chromosome condensAtion. These chAnges Also occurred in the presence of emetine (An inhibitor of protein synthesis) And Aphidicolin (An inhibitor of DNA synthesis). It is suggested thAt CAlyculin A induced these chAnges in the seA urchin eggs by inhibiting the Activity of protein phosphAtAse 1.