Neutrophils lacking phosphoinositide 3-kinase gamma show loss of directionality during N-formyl-Met-Leu-Phe-induced chemotaxis.
Confocal imaging and time-lapsed videomicroscopy were used to study the directionality, motility, rate of cell movement, and morphologies of phosphoinositide 3-kinase gamma (PI3K)gamma(-/-) neutrophils undergoing chemotaxis in Zigmond chambers containing N-formyl-Met-Leu-Phe gradients. Most of the PI3Kgamma(-/-) neutrophils failed to translocate up the chemotactic gradient. A partial reduction in cell motility and abnormal morphologies were also observed. In the wild-type neutrophils, the pleckstrin homology domain-containing protein kinase B (AKT) and F-actin colocalize to the leading edge of polarized neutrophils oriented toward the gradient, which was not observed in PI3Kgamma(-/-) neutrophils. In PI3Kgamma(-/-) neutrophils, AKT staining consistently failed to perfectly overlap with the F-actin. This failure was observed as an F-actin-filled region of 2.3 +/- 0.5 microm between AKT and the cell membrane. These data suggest that PI3Kgamma regulates neutrophil chemotaxis primarily by controlling the direction of cell migration and the intracellular colocalization of AKT and F-actin to the leading edge.
Hannigan
Michael
M
Department of Pathology, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030, USA.
Zhan
Lijun
L
Li
Zhong
Z
Ai
Youxi
Y
Wu
Dianqing
D
Huang
Chi-Kuang
CK
D000199:Actins / Q000378:metabolism; D000818:Animals; D002634:Chemotaxis, Leukocyte / Q000187:drug effects*; D058544:Class Ib Phosphatidylinositol 3-Kinase; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism; D017353:Gene Deletion; D007527:Isoenzymes / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018715:Microscopy, Video; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology*; D009504:Neutrophils / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology*; D019869:Phosphatidylinositol 3-Kinases / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt
D000199:Actins; D058544:Class Ib Phosphatidylinositol 3-Kinase; D007527:Isoenzymes; D009240:N-Formylmethionine Leucyl-Phenylalanine; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; C546764:Pik3cg protein, mouse