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Type I phosphatidylinositol 4-phosphate 5-kinase controls neutrophil polarity and directional movement

2007; Rockefeller University Press; Volume: 179; Issue: 7 Linguagem: Inglês

10.1083/jcb.200705044

1540-8140

Rosa Ana Lacalle, Rosa M. Peregil, Juan Pablo Albar, Ernesto Merino, Carlos Martı́nez-A, Isabel Mérida, Santos Mañes,

Cell Adhesion Molecules Research

Directional cell movement in response to external chemical gradients requires establishment of front-rear asymmetry, which distinguishes an up-gradient protrusive leading edge, where Rac-induced F-actin polymerization takes place, and a down-gradient retractile tail (uropod in leukocytes), where RhoA-mediated actomyosin contraction occurs. The signals that govern this spatial and functional asymmetry are not entirely understood. We show that the human type I phosphatidylinositol 4-phosphate 5-kinase isoform beta (PIPKIbeta) has a role in organizing signaling at the cell rear. We found that PIPKIbeta polarized at the uropod of neutrophil-differentiated HL60 cells. PIPKIbeta localization was independent of its lipid kinase activity, but required the 83 C-terminal amino acids, which are not homologous to other PIPKI isoforms. The PIPKIbeta C terminus interacted with EBP50 (4.1-ezrin-radixin-moesin (ERM)-binding phosphoprotein 50), which enabled further interactions with ERM proteins and the Rho-GDP dissociation inhibitor (RhoGDI). Knockdown of PIPKIbeta with siRNA inhibited cell polarization and impaired cell directionality during dHL60 chemotaxis, suggesting a role for PIPKIbeta in these processes.