We discovered a previously uncharacterized moss-specific protein, Rosetta NATD-MAPK 1 (RAK1) in Physcomitrium patens, which uniquely integrates MAP kinase (MAPK)-dependent signaling with N-acetyltransferase activity. Through phenotypical and biochemical analyses, we characterized RAK1 function in the regulation of the 2D-to-3D growth transition. We identified differential acetylation events associated with metabolic reprogramming in rak1 mutants and demonstrated that RAK1 has acetyltransferase activity enhanced by MAPK domain activation. Consistently, RAK1 was found to interact with proteins involved in metabolic processes. Collectively, this study uncovers a previously unknown multidomain protein and provides mechanistic insights into the interplay of post-translational modifications during developmental reprogramming.
Luxán‐Hernández et al. (Wed,) studied this question.