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Identifier

000465762

Title

The role of the plant cell border in cell fate

Alternative Title

Ο ρόλος του ορίου των φυτικών κυττάρων στην κυτταρική μοίρα

Author

Μεντζελοπούλου, Ανδριανή Σ

Thesis advisor

Μόσχου, Παναγιώτης

Reviewer

Σαρρής, Παναγιώτης
Παυλόπουλος, Αναστάσιος
Καλαντίδης, Κρίτωνας
Βιδάκη, Μαρίνα
Φιλιππίδη, Εμμανουέλα
Σπηλιανάκης, Χαράλαμπος

Abstract

Molecular condensation is crucial for polarity establishment and stress responses in biological systems. However, the role of condensation in plants is still fragmentary. In the first part of this PhD thesis, I will refer to a cytoplasmic condensate, like the condensate of processing bodies (PBs). I will describe PBs by deciphering at first their protein composition, using the PB core component DECAPPIN PROTEIN 1 (DCP1) as a bait. It is known that PBs reside in the cytoplasm. However, protein datasets revealed a big network of proteins related to the plasma membrane and to the trafficking of vesicles. Thus, I will approach how these condensates can become membrane–bound or be associated with membrane compartments. Additionally, I found that PBs properties can be regulated by the actin polymerization cAMP receptor (SCAR)–WASP family verprolin homologous (WAVE) complex, as another network of proteins in PBs is related to actin remodelling. The SCAR/WAVE complex interacts with DCP1 at cell edges/vertices of the Arabidopsis root and facilitates the actin nucleation process and directional growth. In the second chapter, I will approach the RNA composition of PBs, defining networks related also to hormonal/wounding responses. The SCAR/WAVE complex enables the RNA release from PBs towards the translation machinery modulating hormonal (ethylene) signalling and plant responses to wounding and regeneration. More specifically, RNAs and their cognate proteins are enriched in PBs and comprise of common networks, named “co-regulons”. These co-regulons are processed in PBs through the interplay between decay and storage and RNAs are released to translation upon stress/wounding to facilitate plant responses. In the third chapter, I will try to delineate how a condensate can affect plasma membrane properties. I will refer to the lipid–transferase and condensate Sec14–like nodulin (SEC– FOURTEEN HOMOLOGUE 8) SFH8, which undergoes a liquid–to–solid state transition at the plasma membrane to maintain the polarity of auxin efflux carriers. I will describe the SFH8 interaction with membranes, through its interaction with the specific lipid phosphatidylserine (PS). SFH8 is linked to PS, as removal of SFH8 or vice versa results in compromised PS clustering on the PM. Thus, this PS-SFH8 link can provide an example of how condensates can affect plasma membrane properties and, thus, root development. Finaly, I will try to describe a mechanosensing probe, which can be used to detect changes in plasma membrane properties. This mechanical–stretch activated sensor deriving from the human mechanosensing channel Piezo1 and expressed in Arabidopsis plants, may be a useful tool for the detection of plasma membrane stretching alterations.

Language

English

Subject

Membrane stretching

Plant condensates

Plasma membrane

Polarity

Processing bodies

RNA biology

Wounding

Βιολογία RNA

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