Arabidopsis SOMATIC EMBRYOGENESIS RECEPTOR KINASE proteins serve brassinosteroid-dependent and -independent signaling pathways.
The Arabidopsis (Arabidopsis thaliana) SOMATIC EMBRYOGENESIS RECEPTOR KINASE (SERK) genes belong to a small family of five plant receptor kinases that are involved in at least five different signaling pathways. One member of this family, BRASSINOSTEROID INSENSITIVE1 (BRI1)-ASSOCIATED KINASE1 (BAK1), also known as SERK3, is the coreceptor of the brassinolide (BR)-perceiving receptor BRI1, a function that is BR dependent and partially redundant with SERK1. BAK1 (SERK3) alone controls plant innate immunity, is also the coreceptor of the flagellin receptor FLS2, and, together with SERK4, can mediate cell death control, all three in a BR-independent fashion. SERK1 and SERK2 are essential for male microsporogenesis, again independent from BR. SERK5 does not appear to have any function under the conditions tested. Here, we show that the different SERK members are only redundant in pairs, whereas higher order mutant combinations only show additive phenotypes. Surprisingly, SERK members that are redundant within one are not redundant in another pathway. We also show that this evolution of functional pairs occurred by a change in protein function and not by differences in spatial expression. We propose that, in plants, closely related receptor kinases have a minimal homo- or heterodimeric configuration to achieve specificity.
Albrecht
Catherine
C
Laboratory of Biochemistry, Wageningen University, 6703 HA Wageningen, The Netherlands. catherine.albrecht@wur.nl
Russinova
Eugenia
E
Kemmerling
Birgit
B
Kwaaitaal
Mark
M
de Vries
Sacco C
SC
D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D060406:Brassinosteroids; D016923:Cell Death; D002777:Cholestanols / Q000378:metabolism; D009154:Mutation; D010641:Phenotype; D010935:Plant Diseases; D051479:Plant Infertility; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D013260:Steroids, Heterocyclic / Q000378:metabolism
D029681:Arabidopsis Proteins; D060406:Brassinosteroids; D002777:Cholestanols; D013260:Steroids, Heterocyclic; D011494:Protein Kinases; C463660:BAK1 protein, Arabidopsis; C440035:SERK1 protein, Arabidopsis; C108270:BRI1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases; C023623:brassinolide