Transcription coactivator that plays a role in the regulation of meristematic function in leaves, stems and inflorescences (PubMed:29437990). Regulates shoot architecture and meristem determinacy (PubMed:29437990). Binds to the inflorescence architecture gene UB3 (unbranched3) (PubMed:29437990). Regulates the expression of several genes involved in inflorescence architecture (PubMed:29437990). Component of a network formed by the microRNA396 (miRNA396), the GRFs and their interacting factors (GIFs) acting in the regulation of meristem function, at least partially through the control of cell proliferation (Probable) (PubMed:26036253). Associates with the core SWI/SNF chromatin-remodeling complex and specific GRFs to tightly regulate the transition between cell division and cell expansion in growing leaves (PubMed:26036253). Interacts with several GRFs (PubMed:29437990, PubMed:26036253). Interacts with GRF10 (PubMed:29437990, PubMed:24854713). Interacts with GRF1 (PubMed:24854713). Expressed in shoots, aerial roots, ears and tassels (Ref.1). Expressed in the shoot apical meristem (SAM), young leaf primordia, leaf margins, inflorescence meristem, floral meristem and spikelet meristem (PubMed:29437990). Dwarf plants with narrow and small leaves, reduced number of branches in the tassel leaves, fasciated ears and sterile florets. Belongs to the SS18 family.