An Arabidopsis MADS-box protein, AGL24, is specifically bound to and phosphorylated by meristematic receptor-like kinase (MRLK).
Intercellular signaling mediated by receptor-like kinases (RLKs) is important for diverse processes in plant development, although downstream intracellular signaling pathways remain poorly understood. Proteins interacting directly with RLK were screened for by yeast two-hybrid assay with the kinase domain as bait. A MADS-box protein, AGL24 was identified as a candidate substrate of MRLK (Meristematic Receptor-Like Kinase), which was named for its spatial expression in shoot and root apical meristems in Arabidopsis: The AGL24 protein specifically interacted with, and was phosphorylated by, the MRLK kinase domain in in vitro assays. The simultaneous expression of AGL24 and MRLK in shoot apices during floral transition suggested that the interaction occurs in plants. Using plants constitutively expressing a fusion protein of AGL24 and green fluorescent protein, the subcellular localization of AGL24 protein was observed exclusively in the nucleus in apical tissues where MRLK was expressed, while AGL24 was localized in both the cytoplasm and the nucleus in tissues where no MRLK expression was detectable. These results suggest that MRLK signaling promotes translocation of AGL24 from the cytoplasm to the nucleus. We propose that the RLK signaling pathway involves phosphorylation of a MADS-box transcription factor.
Fujita
Hidetomo
H
Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 630-0192 Japan.
Takemura
Miho
M
Tani
Emi
E
Nemoto
Kyoko
K
Yokota
Akiho
A
Kohchi
Takayuki
T
D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D026161:MADS Domain Proteins / Q000235:genetics* / Q000378:metabolism; D018519:Meristem / Q000201:enzymology / Q000235:genetics*; D010766:Phosphorylation; D018520:Plant Shoots / Q000235:genetics / Q000378:metabolism; D011494:Protein Kinases / Q000235:genetics* / Q000378:metabolism; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology
C478065:AGL24 protein, Arabidopsis; D029681:Arabidopsis Proteins; D008164:Luminescent Proteins; D026161:MADS Domain Proteins; D011956:Receptors, Cell Surface; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D011494:Protein Kinases; D020794:Receptor Protein-Tyrosine Kinases