Linked Life Data

21734039

Source:http://linkedlifedata.com/resource/pubmed/id/21734039

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
18
pubmed:dateCreated
2011-8-18
pubmed:abstractText
The mammalian target of rapamycin (mTOR) kinase is present in 2 functionally distinct complexes, mTOR complex 1 (mTORC1) and complex 2 (mTORC2). Active mTORC1 mediates phosphorylation of eIF4E-binding protein (4E-BP) and p70 S6 kinase (S6K), which is important for maintaining translation. During human cytomegalovirus (HCMV) infection, cellular stress responses are activated that normally inhibit mTORC1; however, previous data show that HCMV infection circumvents stress responses and maintains mTOR kinase activity. Amino acid deprivation is a stress response that normally inhibits mTORC1 activity. Amino acids can signal to mTORC1 through the Rag proteins, which promote the colocalization of mTORC1 with its activator Rheb-GTP in a perinuclear region, thereby inducing 4E-BP and S6K phosphorylation. As expected, our results show that amino acid depletion in mock-infected cells caused loss of mTORC1 activity and loss of the perinuclear localization; however, there was no loss of activity or perinuclear localization in HCMV-infected cells where the perinuclear localization of Rheb-GTP and mTOR coincided with the perinuclear assembly compartment (AC). This suggested that HCMV infection bypasses normal Rag-dependent amino acid signaling. This was demonstrated by short hairpin RNA (shRNA) depletion of Rag proteins, which had little effect on mTORC1 activity in infected cells but inhibited activity in mock-infected cells. Our data show that HCMV maintains mTORC1 activity in an amino acid- and Rag-independent manner through the colocalization of mTOR and Rheb-GTP, which occurs in association with the formation of the AC, thus bypassing inhibition that may result from lowered amino acid levels.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
1098-5514
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
85
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
9369-76
pubmed:meshHeading
pubmed:year
2011
pubmed:articleTitle
Human cytomegalovirus infection maintains mTOR activity and its perinuclear localization during amino acid deprivation.
pubmed:affiliation
Department of Cancer Biology, 314 Biomedical Research Building, 421 Curie Blvd., School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6142, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural