Constitutive signaling activity of a receptor-associated protein links fertilization with embryonic patterning in Arabidopsis thaliana
| Autor: | Emily Eilbert, Lisa Yasmin Asseck, Christopher Grefen, Melanie Hildebrandt, Daniel Slane, Patrick Bürgel, Kai Wang, Martin Bayer, Ancilla Neu, Wolfgang Lukowitz, Martina Kolb, Agnes Henschen, Thomas J. Musielak |
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| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
0106 biological sciences
Zygote Arabidopsis Flowers Protein Serine-Threonine Kinases 01 natural sciences 03 medical and health sciences Gene Expression Regulation Plant Arabidopsis thaliana Yoda 030304 developmental biology 0303 health sciences Multidisciplinary MAP kinase kinase kinase biology Arabidopsis Proteins fungi food and beverages Gene Expression Regulation Developmental Embryo biology.organism_classification Cell biology PNAS Plus Seeds Signal transduction Suspensor 010606 plant biology & botany Signal Transduction |
| Popis: | In flowering plants, the asymmetrical division of the zygote is the first hallmark of apical-basal polarity of the embryo and is controlled by a MAP kinase pathway that includes the MAPKKK YODA (YDA). In Arabidopsis, YDA is activated by the membrane-associated pseudokinase SHORT SUSPENSOR (SSP) through an unusual parent-of-origin effect: SSP transcripts accumulate specifically in sperm cells but are translationally silent. Only after fertilization is SSP protein transiently produced in the zygote, presumably from paternally inherited transcripts. SSP is a recently diverged, Brassicaceae-specific member of the BRASSINOSTEROID SIGNALING KINASE (BSK) family. BSK proteins typically play broadly overlapping roles as receptor-associated signaling partners in various receptor kinase pathways involved in growth and innate immunity. This raises two questions: How did a protein with generic function involved in signal relay acquire the property of a signal-like patterning cue, and how is the early patterning process activated in plants outside the Brassicaceae family, where SSP orthologs are absent? Here, we show that Arabidopsis BSK1 and BSK2, two close paralogs of SSP that are conserved in flowering plants, are involved in several YDA-dependent signaling events, including embryogenesis. However, the contribution of SSP to YDA activation in the early embryo does not overlap with the contributions of BSK1 and BSK2. The loss of an intramolecular regulatory interaction enables SSP to constitutively activate the YDA signaling pathway, and thus initiates apical-basal patterning as soon as SSP protein is translated after fertilization and without the necessity of invoking canonical receptor activation. |
| Databáze: | OpenAIRE |
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