Methods for Detection of Protein Interactions with Plasmodesmata-Localized Reticulons

Area of Science:

• Plant cell biology
• Molecular plant science
• Membrane biophysics

Background:

• Plant reticulon (RTN) proteins are known to shape the endoplasmic reticulum (ER) membrane through oligomerization.
• Two RTN proteins are present in the plasmodesmata (PD) proteome, suggesting a role in desmotubule formation.
• Desmotubules are ER-derived structures crucial for intercellular communication in plants.

Purpose of the Study:

• To identify novel interaction partners of plasmodesmata-resident reticulon proteins RTN3 and RTN6.
• To investigate the direct protein-protein interactions of RTN3 and RTN6 in planta.
• To elucidate the role of RTN3 and RTN6 in the formation of desmotubules during primary plasmodesmata formation at cytokinesis.

Main Methods:

• Immunoprecipitation using GFP-Trap®_A beads to isolate and identify interacting proteins.
• Förster Resonance Energy Transfer - Fluorescence Lifetime Imaging Microscopy (FRET-FLIM) to detect and quantify direct protein-protein interactions in living plant cells.
• Utilizing tobacco (Nicotiana tabacum) as the model organism.

Main Results:

• Identification of potential novel interaction partners for RTN3 and RTN6 within the plasmodesmata proteome.
• Quantification of direct protein-protein interactions between RTN3 and RTN6 and their partners in planta.
• Evidence supporting the involvement of RTN3 and RTN6 in the structural organization of plasmodesmata.

Conclusions:

• The study successfully identified interaction partners for PD-resident RTNs, providing insights into desmotubule formation mechanisms.
• Direct interactions confirm the functional relevance of these RTNs in plant intercellular connections.
• Findings contribute to understanding ER dynamics and cell-to-cell communication in plants.