Linked Life Data

1314839

Source:http://linkedlifedata.com/resource/pubmed/id/1314839

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
1992-5-26
pubmed:abstractText
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 nM), cells became blocked in a metaphase-like mitotic state beginning 6-8 h after initial treatment. Spindle microtubules were present throughout the period of the mitotic block, but were not stabilized since they remained sensitive to nocodazole depolymerization. With increasing length of the mitotic block chromosome alignment at the metaphase plate was disrupted and multipolar spindles developed. Cells continued to accumulate in mitosis for at least 24 h, indicating that at these low concentrations okadaic acid was not cytotoxic, but rather acted as a cytostatic agent. Upon release of the okadaic acid block, mitotic LLC-PK cells recovered and completed anaphase. After extended periods of treatment some cells were able to escape the okadaic acid-induced mitotic block. These cells were multinucleate and had undergone cytokinesis in the absence of chromosome segregation. At higher concentrations of okadaic acid (0.5-1.0 microM), mitosis was blocked within 30-60 min of treatment. However, within 90-120 min treated cells rounded up and detached from the monolayer, regardless of whether they were in interphase or mitosis. Cytoplasmic microtubules were depolymerized in the detached cells, and these cells could not recover from the cytotoxic effects of such high concentrations of okadaic acid. Thus, differential effects of the phosphatase inhibitor could be demonstrated, depending upon the concentration of okadaic acid applied to the cultures. The okadaic acid-induced mitotic blockage was probably due to the inhibition of a type 2A protein phosphatase that is involved in the transition from metaphase to anaphase.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0021-9533
pubmed:author
pubmed:issnType
Print
pubmed:volume
101 ( Pt 1)
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
79-91
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Inhibition of mitosis by okadaic acid: possible involvement of a protein phosphatase 2A in the transition from metaphase to anaphase.
pubmed:affiliation
Department of Cell Biology, Ohio State University, Columbus 43210.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't