Phosphorylation-dependent protein modification by protein kinases plays an important role in regulating eukaryotic cell proliferation in response to different environmental stresses. For instance, dual-specificity tyrosine phosphorylation-regulated kinases (DYRKs) are widely conserved in eukaryotes and are known to function in response to nutritional status. However, their physiological functions in land plants are not fully understood. Shinkawa et al. (on pp. 1063–1077) identified four genes encoding DYRK-homologous proteins in the liverwort Marchantia polymorpha. Mutagenesis analyses further showed that of these, MpYAK1 plays a role in cell division of the apical notch regions, in dormancy of asexually reproductive organs -or gemmae- in gemma cups, and in the development of sexual organs in response to certain light conditions and nutrient signaling.