title: Ectopic expression of cyclase associated protein CAP restores the streaming and aggregation defects of adenylyl cyclase a deficient Dictyostelium discoideum cells.
abstract: BACKGROUND
  Cell adhesion, an integral part of D. discoideum development, is important for morphogenesis and regulated gene expression in the multicellular context and is required to trigger cell-differentiation. G-protein linked adenylyl cyclase pathways are crucially involved and a mutant lacking the aggregation specific adenylyl cyclase ACA does not undergo multicellular development.
  
  
  RESULTS
  Here, we have investigated the role of cyclase-associated protein (CAP), an important regulator of cell polarity and F-actin/G-actin ratio in the aca- mutant. We show that ectopic expression of GFP-CAP improves cell polarization, streaming and aggregation in aca- cells, but it fails to completely restore development. Our studies indicate a requirement of CAP in the ACA dependent signal transduction for progression of the development of unicellular amoebae into multicellular structures. The reduced expression of the cell adhesion molecule DdCAD1 together with csA is responsible for the defects in aca- cells to initiate multicellular development. Early development was restored by the expression of GFP-CAP that enhanced the DdCAD1 transcript levels and to a lesser extent the csA mRNA levels.
  
  
  CONCLUSIONS
  Collectively, our data shows a novel role of CAP in regulating cell adhesion mechanisms during development that might be envisioned to unravel the functions of mammalian CAP during animal embryogenesis.
authors.affiliation: Center for Biochemistry, Medical Faculty, University of Cologne, 50931 Köln, Germany. hameeda.sultana@yale.edu
authors.forename: Hameeda
authors.initials: H
authors.lastname: Sultana
authors.forename: Girish
authors.initials: G
authors.lastname: Neelakanta
authors.forename: Francisco
authors.initials: F
authors.lastname: Rivero
authors.forename: Rosemarie
authors.initials: R
authors.lastname: Blau-Wasser
authors.forename: Michael
authors.initials: M
authors.lastname: Schleicher
authors.forename: Angelika A
authors.initials: AA
authors.lastname: Noegel
mesh_terms: D000262:Adenylyl Cyclases / Q000172:deficiency*; D002448:Cell Adhesion; D016764:Cell Polarity; D003598:Cytoskeletal Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D004023:Dictyostelium / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000096:biosynthesis; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D015800:Protozoan Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D014158:Transcription, Genetic
chemical_list: D003598:Cytoskeletal Proteins; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D000262:Adenylyl Cyclases