Co-operation of phosphatidylinositol transfer protein with phosphoinositide 3-kinase gamma in the formylmethionyl-leucylphenylalanine-dependent production of phosphatidylinositol 3,4,5-trisphosphate in human neutrophils.
Phosphoinositide 3-kinase (PI3K) and its product phosphatidylinositol 3,4,5-trisphosphate (PIP3) play an essential role in the regulation of neutrophil functions by the chemoattractant formylmethionyl-leucylphenylalanine (FMLP). Here we show that permeabilization of human neutrophils leads to loss of cytosolic components, including PI3Kgamma, and causes the loss of FMLP-dependent production of PIP3. FMLP-sensitive synthesis of PIP3 could be restored by reconstitution of permeabilized neutrophils with recombinant PI3Kgamma. Admixture of recombinant phosphatidylinositol transfer protein (PITP) to the reconstitution cocktail produced a further increase of PIP3 synthesis, whereas pertussis toxin suppressed the FMLP-dependent production of PIP3. We conclude that FMLP-sensitive PIP3 formation in human neutrophils involves the FMLP receptor, heterotrimeric G-proteins of the Gi type, PI3Kgamma and PITP.
Kular
G
G
Max Planck Research Unit 'Molecular Cell Biology', Medical Faculty, University of Jena, 07747 Jena, Federal Republic of Germany.
Loubtchenkov
M
M
Swigart
P
P
Whatmore
J
J
Ball
A
A
Cockcroft
S
S
Wetzker
R
R
D001426:Bacterial Proteins; D002352:Carrier Proteins / Q000378:metabolism*; D002463:Cell Membrane Permeability / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D019204:GTP-Binding Proteins / Q000378:metabolism; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D006801:Humans; D015151:Immunoblotting; D008565:Membrane Proteins; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology*; D009504:Neutrophils / Q000378:metabolism*; D037342:Pertussis Toxin; D019869:Phosphatidylinositol 3-Kinases; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism; D018129:Phosphatidylinositol Phosphates / Q000096:biosynthesis*; D049294:Phospholipid Transfer Proteins; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction; D013301:Streptolysins / Q000494:pharmacology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D001426:Bacterial Proteins; D002352:Carrier Proteins; D008565:Membrane Proteins; D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates; D049294:Phospholipid Transfer Proteins; D011994:Recombinant Proteins; D013301:Streptolysins; D010566:Virulence Factors, Bordetella; C060974:phosphatidylinositol 3,4,5-triphosphate; C025964:streptolysin O; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D009240:N-Formylmethionine Leucyl-Phenylalanine; D037342:Pertussis Toxin; D019869:Phosphatidylinositol 3-Kinases; D017853:Phosphotransferases (Alcohol Group Acceptor); D019204:GTP-Binding Proteins