A Dictyostelium SH2 adaptor protein required for correct DIF-1 signaling and pattern formation

► LrrB null (lrrB-) slugs are highly defective in phototaxis and thermotaxis, perhaps because the anterior, pstO prestalk sub-region of the slug is aberrant. ► There are many changes in gene expression in the null mutant, especially in prestalk-specific transcripts. ► The posterior, pstB sub-population of the slug is absent in the lrrB- mutant and the derivative structures are aberrant or missing. ► The lrrB- mutant is highly defective in ecmB induction by the polyketide DIF-1 but only marginally defective in ecmA induction, so the mutation partially uncouples these two inductive events. ► SH2 domain signaling in Dictyostelium mirrors that of animal cells in utilizing single adaptor proteins in multiple signaling pathways.