title: Microarray phenotyping places cyclase associated protein CAP at the crossroad of signaling pathways reorganizing the actin cytoskeleton in Dictyostelium.
abstract: Large-scale gene expression analysis has been applied recently to uncover groups of genes that are co-regulated in particular processes. Here we undertake such an analysis on CAP, a protein that participates in the regulation of the actin cytoskeleton and in cAMP signaling in Dictyostelium. microarray analysis revealed that loss of CAP altered the expression of many cytoskeletal components. One of these, the Rho GDP-dissociation inhibitor RhoGDI1, was analyzed further. RhoGDI1 null cells expressed lower amounts of CAP, which failed to accumulate predominantly at the cell cortex. To further position CAP in the corresponding signal transduction pathways we studied CAP localization and cellular functioning in mutants that have defects in several signaling components. CAP showed correct localization and dynamics in all analyzed strains except in mutants with deficient cAMP dependent protein kinase A activity, where CAP preferentially accumulated in crown shaped structures. Ectopic expression of CAP improved the efficiency of phagocytosis in Gbeta-deficient cells and restored the pinocytosis, morphology and actin distribution defects in a PI3 kinase double mutant (pi3k1/2 null). Our results show that CAP acts at multiple crossroads and links signaling pathways to the actin cytoskeleton either by physical interaction with cytoskeletal components or through regulation of their gene expression.
authors.affiliation: Center for Biochemistry, Medical Faculty, University of Cologne, 50931 Köln, Germany.
authors.forename: Hameeda
authors.initials: H
authors.lastname: Sultana
authors.forename: Girish
authors.initials: G
authors.lastname: Neelakanta
authors.forename: Ludwig
authors.initials: L
authors.lastname: Eichinger
authors.forename: Francisco
authors.initials: F
authors.lastname: Rivero
authors.forename: Angelika A
authors.initials: AA
authors.lastname: Noegel
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism; D000199:Actins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D048868:Adaptor Proteins, Signal Transducing / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D000818:Animals; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism*; D004023:Dictyostelium / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D044387:GTP-Binding Protein beta Subunits / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D020730:Guanine Nucleotide Dissociation Inhibitors / Q000235:genetics / Q000378:metabolism; D008840:Microfilament Proteins / Q000172:deficiency / Q000502:physiology*; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D010588:Phagosomes / Q000187:drug effects / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism; D010873:Pinocytosis / Q000187:drug effects / Q000502:physiology; D011554:Pseudopodia / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology*; D053778:Thiazolidines / Q000494:pharmacology; D020741:rho GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors
chemical_list: D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; D019086:Bridged Bicyclo Compounds, Heterocyclic; D044387:GTP-Binding Protein beta Subunits; D020730:Guanine Nucleotide Dissociation Inhibitors; D008840:Microfilament Proteins; D053778:Thiazolidines; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors; D019869:Phosphatidylinositol 3-Kinases; D017868:Cyclic AMP-Dependent Protein Kinases; D020741:rho GTP-Binding Proteins; C037068:latrunculin B