E-Locus - Institutional Repository of the University of Crete

Home Collections Type of Work Post-graduate theses

Post-graduate theses

Search command : Author="Καραδήμας" And Author="Ευάγγελος"

Current Record: 12 of 6646

[Add to Basket]

Identifier

000466103

Title

Διαλεύκανση του ρόλου των HSP90 στο μονοπάτι μεταγωγής σήματος των Βρασσινοστεροειδών

Alternative Title

Elucidation of the role of HSP90 in Brassinosteroids signaling pathway

Author

Γκριτζάς, Ραφαήλ Α

Thesis advisor

Χατζόπουλος, Πολυδεύκης

Reviewer

Μηλιώνη, Δήμητρα
Καλαντίδης, Κρίτων

Abstract

The HSP90 (HEAT SHOCK PROTEIN 90) play an active role in fine-tuning physiological responses and developmental processes in the plant Arabidopsis thaliana. The multifaceted function of HSP90 is achieved through a wide range of molecular networks in which they are involved, interacting, dissociating, and connecting. A notable example is the Brassinosteroid pathway, where HSP90 naturally interacts with members of the heterodimeric receptor BRI1/BAK1, the kinase BIN2, and the transcription factors BES1/BZR1. The impact of HSP90 on maintaining the membrane and intracellular levels of BRI1 suggests their involvement in receptor’s recycling mechanism. This is supported by data indicating a similar effect on the auxin transporter PIN1. In the context of this thesis, observations were made using fluorescence confocal microscopy techniques, focusing on the differential subcellular localization and changes in membrane and overall levels of the BRI1 receptor in the Arabidopsis root after pharmacological or genetic reduction of HSP90 activity. Simultaneously, efforts were made to identify the points of BRI1 receptor recycling pathway involving HSP90 through comparative phenotypic analysis using drugs that block recycling (Concanamycin A and Wortmannin) at specific sites. In addition, the possibility of interaction between cytoplasmic HSP90 and the demethylation of histones H3K27, RELATIVE OF EARLY FLOWERING 6 (REF6), was investigated, which, among other things, is involved in the expression of brassinosteroid-regulated genes. Summarizing all results, HSP90 plays a central role in fine-tuning the brassinosteroid signal transduction pathway by engaging in the recycling pathways of BRI1 and controlling the epigenetic status of brassinosteroid-responsive genes, interacting with REF6.

Language

Greek

Subject

Brassinosteroid receptor

Early endosomes

Endocytosis

Heat shock proteins

Late endosomes

Lytic vacuoles

Pharmacological inhibition

Plasma membrane

Recycling