Dock180/Elmo proteins are critical regulators of phagocytosis,macropinocytosis and chemotaxis in Dictyostelium
type: CreativeWork
description: NOTE: THE SPECIAL CHARACTERS IN THIS ABSTRACT CANNOT BE DISPLAYED CORRECTLY ON THIS PAGE. PLEASE REFER TO ABSTRACT IN THE ATTACHED FILE FOR AN ACCURATE DISPLAY. In this study, we report the characterization of Dock/Elmo proteins, a novel family of RacGEF's in Dictyostelium discoideum and describe their role in phagocytosis, macropinocytosis and CAMP mediated chemotactic cell movement. Aggregation competent Dictyostelium cells can detect and move up CAMP gradients. cAMP stimulation causes a transient localized increase in phosphatidyl inositol (3,4,5) tris phosphate (PIP3) concentration in the plasma membrane at the cell's leading edge. PIP3 binding domain containing RacGEF's are thought to mediate the cAMP signal through the activation of Racs to localised actin polymerization, which results in further extension of the leading edge in the direction of the CAMP gradient. However inhibition of PIP3 formation, through inhibition of P13K activity,results only in a partial defect of chemotaxis, implying that there may exist other signalling pathways that mediate the CAMP signal to the cytoskeleton. Members of the Dock family form a novel class of Rac activators and deletion of dock in Drosophila and C. elegans results in chemotaxis and phagocytosis defects. We have identified the 8 dock genes and 4 elmo genes in the Dictyostelium genome, which we named dockA-H and elmo1-4. To investigate the role of Dock/Elmo, we generated null mutant strains (dockA""ll, dockBn"ºi, dockA/Bnuu, dockCii°, dockD'dockGuil, dockI(wfl, elmolni° and elmo1/dockB' ) by gene disruption using homologous recombination.In our study, knockout dock genes in Dictyostelium results in numerous defects. dockA"""cells show a slow chemotactic response to CAMP and reduced rate in macropinocytosis. dockA""ll slugs show poor phototaxis. dock8""`l cells grow slowly in the axenic medium and are defective in chemotaxis, macropinocytosis and phagocytosis. dockA/8 double mutant cells show stronger defects in chemota…
abstract: NOTE: THE SPECIAL CHARACTERS IN THIS ABSTRACT CANNOT BE DISPLAYED CORRECTLY ON THIS PAGE. PLEASE REFER TO ABSTRACT IN THE ATTACHED FILE FOR AN ACCURATE DISPLAY. In this study, we report the characterization of Dock/Elmo proteins, a novel family of RacGEF's in Dictyostelium discoideum and describe their role in phagocytosis, macropinocytosis and CAMP mediated chemotactic cell movement. Aggregation competent Dictyostelium cells can detect and move up CAMP gradients. cAMP stimulation causes a transient localized increase in phosphatidyl inositol (3,4,5) tris phosphate (PIP3) concentration in the plasma membrane at the cell's leading edge. PIP3 binding domain containing RacGEF's are thought to mediate the cAMP signal through the activation of Racs to localised actin polymerization, which results in further extension of the leading edge in the direction of the CAMP gradient. However inhibition of PIP3 formation, through inhibition of P13K activity,results only in a partial defect of chemotaxis, implying that there may exist other signalling pathways that mediate the CAMP signal to the cytoskeleton. Members of the Dock family form a novel class of Rac activators and deletion of dock in Drosophila and C. elegans results in chemotaxis and phagocytosis defects. We have identified the 8 dock genes and 4 elmo genes in the Dictyostelium genome, which we named dockA-H and elmo1-4. To investigate the role of Dock/Elmo, we generated null mutant strains (dockA""ll, dockBn"ºi, dockA/Bnuu, dockCii°, dockD'dockGuil, dockI(wfl, elmolni° and elmo1/dockB' ) by gene disruption using homologous recombination.In our study, knockout dock genes in Dictyostelium results in numerous defects. dockA"""cells show a slow chemotactic response to CAMP and reduced rate in macropinocytosis. dockA""ll slugs show poor phototaxis. dock8""`l cells grow slowly in the axenic medium and are defective in chemotaxis, macropinocytosis and phagocytosis. dockA/8 double mutant cells show stronger defects in chemota…
author: Wang, Jun
language: eng
date published: 2006
date modified: 2026-07-24T02:07:31Z
provider: University of Dundee
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Dundee