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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2011-2-25
pubmed:abstractText
The inositol pyrophosphates are multifunctional signalling molecules. One of the families of enzymes that synthesize the inositol pyrophosphates are the Vip1/PPIP5Ks (PP-InsP5 kinases). The kinase domains in Vip1/PPIP5Ks have been mapped to their N-terminus. Each of these proteins also possess a phosphatase-like domain of unknown significance. In the present study, we show that this phosphatase-like domain is not catalytically active. Instead, by using SPR (surface plasmon resonance) to study protein binding to immobilized lipid vesicles, we show that this domain is specialized for binding PtdIns(3,4,5)P3 (PPIP5K1 K(d)=96 nM; PPIP5K2 K(d)=705 nM). Both PtdIns(3,4)P2 and PtdIns(4,5)P2 are significantly weaker ligands, and no significant binding of PtdIns(3,5)P2 was detected. We confirm the functional importance of this domain in inositol lipid binding by site-directed mutagenesis. We present evidence that the PtdIns(3,4,5)P3-binding domain is an unusual hybrid, in which a partial PH (pleckstrin homology) consensus sequence is spliced into the phosphatase-like domain. Agonist-dependent activation of the PtdIns 3-kinase pathway in NIH 3T3 cells drives translocation of PPIP5K1 from the cytosol to the plasma membrane. We have therefore demonstrated receptor-regulated compartmentalization of inositol pyrophosphate synthesis in mammalian cells.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
1470-8728
pubmed:author
pubmed:issnType
Electronic
pubmed:day
15
pubmed:volume
434
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
415-26
pubmed:dateRevised
2011-9-6
pubmed:meshHeading
pubmed-meshheading:21222653-Amino Acid Sequence, pubmed-meshheading:21222653-Animals, pubmed-meshheading:21222653-Binding Sites, pubmed-meshheading:21222653-Cell Compartmentation, pubmed-meshheading:21222653-Cell Membrane, pubmed-meshheading:21222653-Consensus Sequence, pubmed-meshheading:21222653-Cytosol, pubmed-meshheading:21222653-Humans, pubmed-meshheading:21222653-Ligands, pubmed-meshheading:21222653-Mice, pubmed-meshheading:21222653-Mutagenesis, Site-Directed, pubmed-meshheading:21222653-NIH 3T3 Cells, pubmed-meshheading:21222653-Phosphatidylinositol Phosphates, pubmed-meshheading:21222653-Phosphotransferases (Phosphate Group Acceptor), pubmed-meshheading:21222653-Protein Binding, pubmed-meshheading:21222653-Protein Structure, Tertiary, pubmed-meshheading:21222653-Protein Transport, pubmed-meshheading:21222653-Receptors, Cell Surface, pubmed-meshheading:21222653-Receptors, Cytoplasmic and Nuclear, pubmed-meshheading:21222653-Surface Plasmon Resonance
pubmed:year
2011
pubmed:articleTitle
Receptor-dependent compartmentalization of PPIP5K1, a kinase with a cryptic polyphosphoinositide binding domain.
pubmed:affiliation
Inositol Signaling Group, Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, NC 27709, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural, Research Support, N.I.H., Intramural