Promotes cell proliferation in the gibberellic acid (GA) signaling pathway, acting downstream of RGA, and possibly through a negative regulation of two cyclin-dependent kinase inhibitors SIM and SMR1. Expressed ubiquitously, mostly in roots, to a lower extent in leaves, floral buds and stems, and, at low levels, in flowers and siliques. In young seedlings, observed in shoot apices and roots and accumulates gradually in the leaf vasculature (PubMed:22492352). Later expressed in inflorescence apices, especially in the center, and in secondary inflorescence meristems (PubMed:22492352). In floral buds and flowers, strongly present in anthers (specifically in the tapetum), ovules and pollen (PubMed:22492352). Induced by gibberellins (GA) in seedlings shoot apices, in tissues containing actively dividing cells (PubMed:22492352). Down-regulated by RGA in the GA signaling pathway (PubMed:22492352). The protein kinase domain is predicted to be catalytically inactive. General retarded growth with small curled leaves and short roots in seedlings, as well as delayed floral transition and lower fertility; these phenotypes are partly due to a reduced cell proliferation. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family.