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Highlights
HIGHLIGHTS Volume 317, Issue 6, April 1, 2011 Eps8 involvement in neuregulin1-ErbB4 mediated migration in the neuronal progenitor cell line ST14A. By Federica Fregnan, Veselin Petrov, Donatella Garzotto, Silvia De Marchis, Nina Offenha¨user, Enrico Grosso, Giovanna Chiorino, Isabelle Perroteau, and Giovanna Gambarotta . . . . . . . . . . . . . . . . . . . . . 757 The tyrosine kinase receptor ErbB4, and its ligand neuregulin1, are candidate susceptibility genes for Schizophrenia and play an important role in the central nervous system development and in adult neurogenesis by modulating neuronal migration. Four receptor isoforms and numerous ligand isoforms have been described. The authors of this paper focused their attention on the study of the genes regulated by two ErbB4 isoforms whose expression provides neuronal progenitor cells with a high migratory activity. They found constitutive up-regulation of Eps8, a multimodular regulator of actin dynamics, and demonstrated its involvement in neuronal migration. These findings underline the importance of proper actin remodeling in motility of neuronal progenitor cells and its fine tuning by signaling pathways downstream tyrosine kinase receptors.
Modulation of Bax mitochondrial insertion and induced cell death in yeast by mammalian protein kinase Ca. By Rui D. Silva, Ste´phen Manon, Jorge Gonc¸alves, Lucı´lia Saraiva, and Manuela Coˆrte-Real . . . . . . . . . . . . . . . . . . . 781 Bax is an important apoptotic player being responsible for the permeabilization of the outer mitochondrial membrane. In order to induce this permeabilization Bax has to translocate from the cytosol to mitochondria through a highly regulated process. PKCa is a classical isoform of the protein kinase C family whose involvement in cell death regulation is not completely understood. By coexpressing Bax and PKCa in yeast Silva et al. showed that PKCa enhances translocation of active Bax to the mitochondria increasing several downstream events such as cytochrome c release and cell death. Moreover, they clearly show that the effect of PKCa is independent of its kinase activity and provided some mechanistic insight on apoptosis regulation by PKCa.
Mis-localization of Arp2 mRNA impairs persistence of directional cell migration. By Guoning Liao, Brittany Simone, and Gang Liu. . . . . . . . . . . . . . . . 812 A hallmark of directional cell migration is actin polymerization in the leading protrusions. Arp2/3 complex promotes actin polymerization and is enriched at the leading front of migrating cells. However, it has been unclear why and how the Arp2/3 complex is targeted to the protrusions. On the basis of previous finding that all the mRNAs encoding the Arp2/3 complex are localized in cell protrusions, Liao et al. now showed that fibroblasts with Arp2 mRNA that was mis-localized to the perinuclear ER compartment exhibited poor migration speed and directionality, even though the Arp2 protein was sufficiently made. This work for the first time highlights the critical role of localized protein synthesis in facilitating Arp2/3 complex assembly and localization for directional cell migration.
Modulation of Bax mitochondrial insertion and induced cell death in yeast by mammalian protein kinase Ca. By Rui D. Silva, Ste´phen Manon, Jorge Gonc¸alves, Lucı´lia Saraiva, and Manuela Coˆrte-Real . . . . . . . . . . . . . . . . . . . 781 Bax is an important apoptotic player being responsible for the permeabilization of the outer mitochondrial membrane. In order to induce this permeabilization Bax has to translocate from the cytosol to mitochondria through a highly regulated process. PKCa is a classical isoform of the protein kinase C family whose involvement in cell death regulation is not completely understood. By coexpressing Bax and PKCa in yeast Silva et al. showed that PKCa enhances translocation of active Bax to the mitochondria increasing several downstream events such as cytochrome c release and cell death. Moreover, they clearly show that the effect of PKCa is independent of its kinase activity and provided some mechanistic insight on apoptosis regulation by PKCa.
Mis-localization of Arp2 mRNA impairs persistence of directional cell migration. By Guoning Liao, Brittany Simone, and Gang Liu. . . . . . . . . . . . . . . . 812 A hallmark of directional cell migration is actin polymerization in the leading protrusions. Arp2/3 complex promotes actin polymerization and is enriched at the leading front of migrating cells. However, it has been unclear why and how the Arp2/3 complex is targeted to the protrusions. On the basis of previous finding that all the mRNAs encoding the Arp2/3 complex are localized in cell protrusions, Liao et al. now showed that fibroblasts with Arp2 mRNA that was mis-localized to the perinuclear ER compartment exhibited poor migration speed and directionality, even though the Arp2 protein was sufficiently made. This work for the first time highlights the critical role of localized protein synthesis in facilitating Arp2/3 complex assembly and localization for directional cell migration.