... that protein phosphatase-1-mediated dephosphorylation of MARCKS largely influences its subcellular localization and the fusion process. Treatment with okadaic acid or tautomycin, which are potent inhibitors of protein phosphatases and cell fusion, was found to reversibly block the MARCKS translocation...

... combined with either cdc25-22 or wee1-50 but not the cdc24-1 temperature-sensitive mutant. The pin1Δ strain showed increased sensitivity to the PP1/PP2A family phosphatase inhibitor, okadaic acid, suggesting that Pin1p plays a role in protein dephosphorylation as a result of its ability to increase...

... investigated the effect of the serine/threonine phosphatase inhibitor okadaic acid on water permeability properties and on aquaporin2 (AQP2) translocation in AQP2-transfected renal CD8 cells. In CD8 cells both forskolin alone and okadaic acid alone increased the osmotic water permeability coefficient P f...

...Madalina Tarsounas; Ronald E. Pearlman; Peter B. Moens ABSTRACT The phosphatase inhibitor okadaic acid accelerates meiotic events in rodent germ cells in culture. Isolated pachytene spermatocytes treated with okadaic acid proceed to a metaphase I arrest in a few hours as opposed to the similar...

... heterochromatin both during G 2 and when premature chromosome condensation is induced. The prematurely condensed state induced by okadaic acid treatment during S-phase culminates with H3 phosphorylation throughout the chromatin, but in an absence of mitotic chromosome morphology, indicating...

... and 2A inhibitor okadaic acid induces morphologically normal chromosome condensation. We now show that okadaic acid also induces two other landmark events of early mitosis, nuclear lamina depolymerization and centrosome separation, in the absence of Cdc2 kinase activity. Okadaic acid-induced entry...

...Patricia M. Vilalta; Liping Zhang; Sarah F. Hamm-Alvarez ABSTRACT To understand how protein phosphorylation modulates cytoskeletal organization, we used immunofluorescence microscopy to examine the effects of okadaic acid, a serine/threonine protein phosphatase inhibitor, and taxol, a microtubule...

... of okadaic acid inhibit dephosphorylation suggesting a PP2A-like phosphatase is responsible. Transfecting τ into CHO cells to act as a ‘reporter’ protein shows a similar dephosphorylation of τ by a PP2A-like phosphatase during the execution phase following induction of apoptosis with UV irradiation...

...James R. Paulson; Jason S. Patzlaff; Amy J. Vallis ABSTRACT Histone H1 is highly phosphorylated in mitotic HeLa cells, but is quickly dephosphorylated in vivo at the end of mitosis and in vitro following cell lysis. We show here that okadaic acid and microcystin-LR block the in vitro...

... that okadaic acid, a potent and specific inhibitor of protein phosphatases PP1and PP2A, uncouples these cycles in living trypanosomes. Cell cycle analysis of treated cells revealed elevated DNA content. Microscopic examination indicated that okadaic acid treatment yielded multinucleate cells with a single...

...-microtubule agents. Here we use in vitro galactosylation to show that increased terminal GlcNAc’s is a general phenomenon that occurs in glycoproteins isolated from nuclear and plasma membrane fractions after cells are arrested in mitosis using colcemid, nocodazole, or okadaic acid. All three agents also...

... and phos-phatases increasing protein phosphorylation. The activa-tion of histone H1 kinase and that of the mitogen-activated protein kinase p42 have been compared during sponta-neous or okadaic acid-induced meiotic reinitiation. In spontaneously maturing oocytes, histone H1 kinase activity increases before...

..., but not cytochalasin B or D, abolished vesicle movements, indicating that these movements were microtubule and not actin-dependent. The frequency of vesicle movements was stimulated maximally sixfold by okadaic acid from a resting value of 1.6 movements/min per m 2 in serum-starved CV-1 cells. Other activators...

... kinase C inhibitor Ro 31-8220 (10 6 to 10 5 M). Ro 31-8220 (10 5 M) alone increased CD18 expression of initially resting cells. Furthermore, the phosphatase inhibitor okadaic acid (5 M) and calyculin A (0.04 μM) suppressed CD18 expression in chemotactic peptide-treated cells, but there was no detectable...

... profilaggrin phosphatase is not a phospho-tyrosyl phosphatase or a type 1 phospho-seryl/phospho-threonyl phosphatase. Dephosphorylation is not affected by EDTA, calcium or magnesium, but is very sensitive to okadaic acid inhibition (IC 50 = 80 pM), suggesting that the enzymatic activity is related...

...Johan Thyberg; Stanislaw Moskalewski ABSTRACT A combination of immunocytochemical and electron microscopic methods was used to study the effects of okadaic acid, a specific inhibitor of protein phosphatase types 1 and 2A, on the Golgi complex and the microtubule system of interphase CHO cells...

...John Lucocq © 1992 by Company of Biologists 1992 mitosis Golgi okadaic acid The Golgi apparatus does not give up its secrets easily. Despite decades of research we still don’t know what the basic building blocks of the Golgi cisternal stack are and how they maintain it’s...

...Sibdas Ghosh; Neidhard Paweletz; Dieter Schroeter ABSTRACT Mitotic HeLa cells were treated with different concentrations of okadaic acid (OA), known to inhibit phosphatase 1 and 2A activities. The cytological effects on the course of mitosis were studied at the light microscopic, immunofluorescence...

... by microinjection), or with the naturally occurring, potent phosphatase inhibitors okadaic acid, micro-cystin-LR or microcystin-RR (administered by perfusion), and we have observed changes in the metaphase transit time that are primarily dependent on the time of initial exposure to the inhibitor. Maximal extensions...

...Dale D. Vandré; Victoria L. Wills ABSTRACT The effects of the protein phosphatase inhibitor okadaic acid were examined using the pig kidney cell line LLC-PK. At relatively low concentrations of the inhibitor (8–40 μM), cells became blocked in a metaphase-like mitotic state beginning 6–8 h after...