InterPro domain: IPR031048

The SERK (somatic embryogenesis receptor kinase) family is involved in a wide spectrum of biological processes, including plant development and disease resistance [ 1 ]. SERKs (SERK1-5) are classified as subgroup II receptor-like kinases (RLKs). SERKs exist as coreceptors of multiple cell surface-receptors perceiving diverse stimuli via ligand-induced heterodimerization and transphosphorylation [ 2 ]. They are involved in at least five different signalling pathways [ 3 ].

Arabidopsis SERK1 and SERK2 are functionally redundant and essential for tapetum specification and pollen development during male sporogenesis [ 4 ]. SERK3, also known as BAK1 (BRASSINOSTEROID INSENSITIVE 1-associated receptor kinase 1), is the coreceptor of the brassinolide (BR)-perceiving receptor BRI1, a function that is BR dependent and partially redundant with SERK1 [ 5 ]. SERK3 controls plant innate immunity and serves as a coreceptor of the flagellin receptor FLS2 [ 5 ]. SERK4 is also involved in innate immunity [ 6 ]. SERK3 and SERK4 are partially redundant in pathogen-induced cell death control [ 7 ]. SERK5 contains a mutation in an important amino acid residue which likely abolishes the kinase activity of SERK [ 7 ].

1. SERK Family Receptor-like Kinases Function as Co-receptors with PXY for Plant Vascular Development. Mol Plant 9, 1406-1414
2. SERKing Coreceptors for Receptors. Trends Plant Sci. 21, 1017-1033
3. Arabidopsis SOMATIC EMBRYOGENESIS RECEPTOR KINASE proteins serve brassinosteroid-dependent and -independent signaling pathways. Plant Physiol. 148, 611-9
4. The Arabidopsis thaliana SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASES1 and 2 control male sporogenesis. Plant Cell 17, 3337-49
5. The receptor-like kinase SERK3/BAK1 is a central regulator of innate immunity in plants. Proc. Natl. Acad. Sci. U.S.A. 104, 12217-22
6. The Arabidopsis leucine-rich repeat receptor-like kinases BAK1/SERK3 and BKK1/SERK4 are required for innate immunity to hemibiotrophic and biotrophic pathogens. Plant Cell 23, 2440-55
7. Genetic evidence for an indispensable role of somatic embryogenesis receptor kinases in brassinosteroid signaling. PLoS Genet. 8, e1002452