Benzene polyphosphates as tools for cell signalling: inhibition of inositol 1,4,5-trisphosphate 5-phosphatase and interaction with the PH domain of protein kinase Balpha.
Novel benzene polyphosphates were synthesised as inositol polyphosphate mimics and evaluated against type-I inositol 1,4,5-trisphosphate 5-phosphatase, which only binds soluble inositol polyphosphates, and against the PH domain of protein kinase Balpha (PKBalpha), which can bind both soluble inositol polyphosphates and inositol phospholipids. The most potent trisphosphate 5-phosphatase inhibitor is benzene 1,2,4-trisphosphate (2, IC(50) of 14 microM), a potential mimic of D-myo-inositol 1,4,5-trisphosphate, whereas the most potent tetrakisphosphate Ins(1,4,5)P(3) 5-phosphatase inhibitor is benzene 1,2,4,5-tetrakisphosphate, with an IC(50) of 4 microM. Biphenyl 2,3',4,5',6-pentakisphosphate (4) was the most potent inhibitor evaluated against type I Ins(1,4,5)P(3) 5-phosphatase (IC(50) of 1 microM). All new benzene polyphosphates are resistant to dephosphorylation by type I Ins(1,4,5)P(3) 5-phosphatase. Unexpectedly, all benzene polyphosphates studied bind to the PH domain of PKBalpha with apparent higher affinity than to type I Ins(1,4,5)P(3) 5-phosphatase. The most potent ligand for the PKBalpha PH domain, measured by inhibition of biotinylated diC(8)-PtdIns(3,4)P(2) binding, is biphenyl 2,3',4,5',6-pentakisphosphate (4, K(i)=27 nm). The approximately 80-fold enhancement of binding relative to parent benzene trisphosphate is explained by the involvement of a cation-pi interaction. These new molecular tools will be of potential use in structural and cell signalling studies.
Mills
Stephen J
SJ
Wolfson Laboratory of Medicinal Chemistry, Department of Pharmacy and Pharmacology, University of Bath, Claverton Down, Bath BA27AY, UK.
Vandeput
Fabrice
F
Trusselle
Melanie N
MN
Safrany
Stephen T
ST
Erneux
Christophe
C
Potter
Barry V L
BV
D001554:Benzene / Q000737:chemistry*; D001665:Binding Sites; D031541:Fluorescence Resonance Energy Transfer; D000072181:Inositol Polyphosphate 5-Phosphatases; D008024:Ligands; D008958:Models, Molecular; D010744:Phosphoric Monoester Hydrolases / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D011122:Polyphosphates / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D017434:Protein Structure, Tertiary; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects*; D013237:Stereoisomerism; D013329:Structure-Activity Relationship
D008024:Ligands; D011122:Polyphosphates; D051057:Proto-Oncogene Proteins c-akt; D010744:Phosphoric Monoester Hydrolases; D000072181:Inositol Polyphosphate 5-Phosphatases; D001554:Benzene