Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
40
pubmed:dateCreated
2004-9-27
pubmed:abstractText
Protein phosphatase 2A (PP2A) is a family of mammalian serine/threonine phosphatases that is involved in the control of many cellular functions including those mediated by extracellular signal-regulated kinase (ERK) signaling. While investigating the reversible antiproliferative effect of the dietary lectin, jacalin, which binds the Thomsen-Friedenreich antigen (galactose beta1-3 N-acetylgalactosamine alpha-), we have found that this lectin (30 microg/ml) induces rapid, transient, tyrosine phosphorylation of putative human HLA-DR-associated protein I (PHAPI, also known as the tumor suppressor pp32) in HT29 human colon cancer cells. This is accompanied by the release of PP2A from association with PHAPI, allowing increased phosphatase activity of PP2A (by 42 +/- 10% at 10 min) and consequent complete dephosphorylation of the ERK kinase, MEK1/2, by 10 min and of ERK1/2 by 60 min. PHAPI knockdown by RNA interference abolished the effects of jacalin on PP2A activation and MEK inhibition. Thus phosphorylation of PHAPI/pp32 is a critical regulatory step in PP2A activation and ERK signaling.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/ANP32A protein, human, http://linkedlifedata.com/resource/pubmed/chemical/Intracellular Signaling Peptides..., http://linkedlifedata.com/resource/pubmed/chemical/MAP Kinase Kinase 1, http://linkedlifedata.com/resource/pubmed/chemical/MAP2K1 protein, human, http://linkedlifedata.com/resource/pubmed/chemical/Mitogen-Activated Protein Kinase 3, http://linkedlifedata.com/resource/pubmed/chemical/Mitogen-Activated Protein Kinase..., http://linkedlifedata.com/resource/pubmed/chemical/Mitogen-Activated Protein Kinases, http://linkedlifedata.com/resource/pubmed/chemical/Phosphoprotein Phosphatases, http://linkedlifedata.com/resource/pubmed/chemical/Plant Lectins, http://linkedlifedata.com/resource/pubmed/chemical/Protein Phosphatase 2, http://linkedlifedata.com/resource/pubmed/chemical/Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Tyrosine, http://linkedlifedata.com/resource/pubmed/chemical/jacalin
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
279
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
41377-83
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Protein phosphatase 2A, a negative regulator of the ERK signaling pathway, is activated by tyrosine phosphorylation of putative HLA class II-associated protein I (PHAPI)/pp32 in response to the antiproliferative lectin, jacalin.
pubmed:affiliation
Departments of Medicine and Human Anatomy and Cell Biology, University of Liverpool, Liverpool L69 3GA, UK. lgyu@liv.ac.uk
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't