1. Ceramides mediate positional signals in Arabidopsis thaliana protoderm differentiation.
- Author
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Kenji Nagata, Toshiki Ishikawa, Maki Kawai-Yamada, Taku Takahashi, and Mitsutomo Abe
- Subjects
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CERAMIDES , *ROOT development , *CELL differentiation , *MULTICELLULAR organisms , *EPIDERMIS - Abstract
The differentiation of distinct cell types in appropriate patterns is a fundamental process in the development of multicellular organisms. In Arabidopsis thaliana, protoderm/epidermis differentiates as a single cell layer at the outermost position. However, little is known about the molecular nature of the positional signals that achieve correct epidermal cell differentiation. Here, we propose that verylong- chain fatty acid-containing ceramides (VLCFA-Cers) mediate positional signals by stimulating the function of ARABIDOPSIS THALIANA MERISTEM LAYER1 (ATML1), a master regulator of protoderm/epidermis differentiation, during lateral root development. We show that VLCFA-Cers, which are synthesized predominantly in the outermost cells, bind to the lipid-binding domain of ATML1. Importantly, this cell type-specific protein-lipid association alters the activity of ATML1 protein and consequently restricts its expression to the protoderm/epidermis through a transcriptional feedback loop. Furthermore, establishment of a compartment, enriched with VLCFAcontaining sphingolipids, at the outer lateral membrane facing the external environment may function as a determinant of protodermal cell fate. Taken together, our results indicate that VLCFA-Cers play a pivotal role in directing protoderm/epidermis differentiation by mediating positional signals to ATML1. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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