Linked Life Data

11691633

Source:http://linkedlifedata.com/resource/pubmed/id/11691633

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2001-11-5
pubmed:abstractText
The freshwater crayfish, Orconectes virilis, shows good anoxia tolerance, enduring 20 h in N(2)-bubbled water at 15 degrees C. Metabolic responses to anoxia by tolerant species often include reversible phosphorylation control over selected enzymes. To analyze the role of serine/threonine kinases and phosphatases in signal transduction during anoxia in O. virilis, changes in the activities of cAMP-dependent protein kinase (PKA) and protein phosphatases 1, 2A, and 2C were measured in tail muscle and hepatopancreas over a time course of exposure to N(2)-bubbled water. A strong increase in the percentage of PKA present as the free catalytic subunit (% PKAc) occurred between 1 and 2 h of anoxia exposure whereas phosphatase activities were strongly reduced. This suggests that PKA-mediated events are important in the initial response by tissues to declining oxygen availability. As oxygen deprivation became severe and prolonged (5-20 h) these changes reversed; the % PKAc fell to below control values and activities of phosphatases returned to or rose above control values. Subcellular fractionation also showed a decrease in PKA associated with the plasma membrane after 20 h anoxia whereas cytosolic PKA content increased. PKAc purified from tail muscle showed a molecular weight of 43.8+/-0.4 kDa, a pH optimum of 6.8, a high affinity for Mg ATP (K(m)=131.0+/-14.4 microM) and Kemptide (K(m)=31.6+/-5.2 microM). Crayfish PKAc was sensitive to temperature change; a break in the Arrhenius plot occurred at approximately 15 degrees C with a 2.5-fold rise in activation energy at temperatures <15 degrees C. These studies demonstrate a role for serine/threonine protein kinases and phosphatases in the metabolic adjustments to oxygen depletion by crayfish organs.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
1096-4959
pubmed:author
pubmed:issnType
Print
pubmed:volume
130
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
565-77
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Protein kinase and phosphatase responses to anoxia in crayfish, Orconectes virilis: purification and characterization of cAMP-dependent protein kinase.
pubmed:affiliation
Institute of Biochemistry and Department of Chemistry, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, Canada K1S 5B6.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't