title: Hypertonic signal promotes stability of Dictyostelium spores via a PKA-independent pathway.
abstract: Differentiation of Dictyostelium spores initiates with rapid encapsulation of prespore cells under the control of cAMP-dependent protein kinase (PKA), followed by further maturation processes involving cytoskeletal reorganization. Constitutive activation of PKA induces precocious formation of viable spores in development and confers the ability to encapsulate under specific submerged conditions. In this study, we show that the stability of these spores depends upon conditions of high osmotic strength during spore differentiation, indicating that a hypertonic signal is required in addition to PKA to induce maturation to stable spores. The formation of stable spores under hypertonic conditions requires high cell density, suggesting the involvement of additional cellular signaling.
authors.affiliation: The Tokyo Metropolitan Institute of Medical Science, Electron Microscopy Center, Honkomagome 3-18-22, Bunkyo-ku, Tokyo 113-8613, Japan. yyamada@rinshoken.or.jp
authors.forename: Yohko
authors.initials: Y
authors.lastname: Yamada
authors.forename: Masazumi
authors.initials: M
authors.lastname: Sameshima
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D004023:Dictyostelium / Q000254:growth & development / Q000502:physiology*; D006982:Hypertonic Solutions; D008828:Microbiological Techniques; D008854:Microscopy, Electron; D009997:Osmotic Pressure; D010766:Phosphorylation; D015398:Signal Transduction / Q000502:physiology*; D033761:Spores, Protozoan / Q000502:physiology / Q000648:ultrastructure
chemical_list: D000199:Actins; D006982:Hypertonic Solutions; D017868:Cyclic AMP-Dependent Protein Kinases