Glycogen synthase kinase 3 homolog (plant) (GSK3-like kinase (plant), also commonly as SK (Shaggy-like kinase))

Glycogen synthase kinase 3 homologs in plants, commonly called GSK3-like kinases or Shaggy-like kinases, are a highly conserved family of protein serine/threonine kinases present in all land plants[2][3][4]. They function as signaling hubs integrating inputs from multiple upstream factors and control numerous downstream processes via phosphorylation. Plant GSK3-like kinases, such as the Arabidopsis BIN2 protein, regulate critical developmental processes (cell growth, flower and stomatal development, root and vascular development) and responses to environmental stresses (drought, cold, salinity, biotic stress), largely through modulating the stability, localization, and activity of various transcription factors and signaling proteins[1][3][4]. Unlike mammalian GSK3s (which are drug targets in human diseases), no approved drugs directly target plant GSK3s, though small-molecule inhibitors are used experimentally to probe their function. Key plant GSK3-like kinases include multiple isoforms such as BIN2, BIL1, and BIL2 in Arabidopsis (collectively termed AtSKs). Their roles are especially prominent in brassinosteroid (BR) hormone signaling, where they typically act as negative regulators by phosphorylating and inactivating BR-responsive transcription factors[3][4]. Misregulation of these kinases in plants can result in severe growth phenotypes, indicating their central role in plant physiology[2][3][4].

Other names

plant GSK3-like kinaseSHAGGY-like kinaseSKAtSK (Arabidopsis thaliana Shaggy-like kinase)BIN2 (Brassinosteroid-insensitive 2, a well-studied isoform)BIL1BIL2

Phosphorylation of key transcription factors and regulatory proteins in plant hormone and stress signaling pathways