Editors' ChoiceCell Biology

Stalking a Second Messenger in Eukaryotes

Science Signaling  04 Sep 2012:
Vol. 5, Issue 240, pp. ec233
DOI: 10.1126/scisignal.2003559

Cyclic di-guanosine monophosphate (cyclic di-GMP), which is generated by diguanylate cyclases (DGCs), participates in various prokaryotic signaling pathways. Chen and Schaap identified a DGC and a biological role for cyclic di-GMP in the social amoeba Dictyostelium discoideum. Food deprivation causes Dictyostelium to aggregate and form mobile slugs, which can subsequently become sessile fruiting bodies with a stalk and a cap that releases spores. Dictyostelium lacking DgcA did not form fruiting bodies, a phenotype that was rescued by expression of DgcA from D. discoideum or from the related Dictyostelid Polysphondylium pallidum. A reporter gene indicated that DgcA was expressed in cells throughout the aggregate, in the anterior region of slugs, and in cap tips and stalks of fruiting bodies. The fruiting body defect of dgca cells was rescued by mixing dgca cells with wild-type cells or by plating dgca cells on agar that had been preconditioned by wild-type or DgcA-overexpressing cells. Application of cyclic di-GMP to cells isolated from aggregates induced the expression of a reporter gene for stalk cell differentiation. This response was also induced by the application of cyclic di-GMP produced in vitro from purified DgcA. Furthermore, application of cyclic di-GMP to V12M2 cells (a strain that forms stalk cells more readily than wild-type strains) resulted in formation of a large central vacuole, a phenotypic change required during stalk cell formation. Thus, cyclic di-GMP mediates stalk cell differentiation in the social amoeba Dictyostelium.

Z.-h. Chen, P. Schaap, The prokaryote messenger c-di-GMP triggers stalk cell differentiation in Dictyostelium. Nature 488, 680–683 (2012). [PubMed]