Cover image

Cover Multiple signaling pathways that ultimately regulate chemotaxis can be attenuated by a single heterotrimeric Gα protein in Dictyostelium discoideum. Shown here is a composite image of Dictyostelium cells moving toward a pipette (gray) that is emitting a chemoattractant. Relative to wild-type cells (blue), gα9-null cells (green) are hyperpolarized and rarely produce lateral pseudopods, indicative of a loss of a negative regulator of chemotaxis. Cells expressing constitutively activated Gα9 (red) display the expected opposite phenotype, are poorly polarized, and produce numerous lateral pseudopods. In the background, a population of gα9-null cells chemotax to form aggregation centers during development. (For details, see Brzostowski et al., 805.)