Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
44
pubmed:dateCreated
2001-10-29
pubmed:abstractText
The ability of intracellular parasites to monitor the viability of their host cells is essential for their survival. The protozoan parasite Toxoplasma gondii actively invades nucleated animal cells and replicates in their cytoplasm. Two to 3 days after infection, the parasite-filled host cell breaks down and the parasites leave to initiate infection of a new cell. Parasite egress from the host cell is triggered by rupture of the host plasma membrane and the ensuing reduction in the concentration of cytoplasmic potassium. The many other changes in host cell composition do not appear be used as triggers. The reduction in the host cell [K(+)] appears to activate a phospholipase C activity in Toxoplasma that, in turn, causes an increase in cytoplasmic [Ca(2+)] in the parasite. The latter appears to be necessary and sufficient for inducing egress, as buffering of cytoplasmic Ca(2+) blocks egress and calcium ionophores circumvent the need for a reduction of host cell [K(+)] and parasite phospholipase C activation. The increase in [Ca(2+)](C) brings about egress by the activation of at least two signaling pathways: the protein kinase TgCDPK1 and the calmodulin-dependent protein phosphatase calcineurin.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
2
pubmed:volume
276
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
41492-501
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
The loss of cytoplasmic potassium upon host cell breakdown triggers egress of Toxoplasma gondii.
pubmed:affiliation
Division of Geographic Medicine, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294-2170, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't