Interaction Dynamics of Plant-Specific Insert Domains from <i>Cynara cardunculus</i>: A Study of Homo- and Heterodimer Formation
Miguel Sampaio,
Sofia Santos,
Ana Marta Jesus,
José Pissarra,
Gian Pietro Di Sansebastiano,
Jonas Alvim,
Cláudia Pereira
Affiliations
Miguel Sampaio
GreenUPorto—Sustainable Agrifood Production Research Centre, INOV4AGRO—Institute for Innovation, Training and Sustainability of Agrifood Production & Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
Sofia Santos
GreenUPorto—Sustainable Agrifood Production Research Centre, INOV4AGRO—Institute for Innovation, Training and Sustainability of Agrifood Production & Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
Ana Marta Jesus
GreenUPorto—Sustainable Agrifood Production Research Centre, INOV4AGRO—Institute for Innovation, Training and Sustainability of Agrifood Production & Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
José Pissarra
GreenUPorto—Sustainable Agrifood Production Research Centre, INOV4AGRO—Institute for Innovation, Training and Sustainability of Agrifood Production & Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
Gian Pietro Di Sansebastiano
DiSTeBA (Department of Biological and Environmental Sciences and Technologies), University of Salento, Via Lecce-Monteroni, Campus ECOTEKNE, 73100 Lecce, Italy
Jonas Alvim
Laboratory of Plant Physiology and Biophysics, Bower Building, University of Glasgow, Glasgow G12 8SU, UK
Cláudia Pereira
GreenUPorto—Sustainable Agrifood Production Research Centre, INOV4AGRO—Institute for Innovation, Training and Sustainability of Agrifood Production & Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
Plant aspartic proteinases (APs) from Cynara cardunculus feature unique plant-specific insert (PSI) domains, which serve as essential vacuolar sorting determinants, mediating the transport of proteins to the vacuole. Although their role in vacuolar trafficking is well established, the exact molecular mechanisms that regulate PSI interactions and functions remain largely unknown. This study explores the ability of PSI A and PSI B to form homo- and heterodimers using a combination of pull-down assays, the mating-based split-ubiquitin system (mbSUS), and FRET-FLIM analyses. Pull-down assays provided preliminary evidence of potential PSI homo- and heterodimer formation. This was conclusively validated by the more robust in vivo mbSUS and FRET-FLIM assays, which clearly demonstrated the formation of both homo- and heterodimers between PSI A and PSI B within cellular environments. These findings suggest that PSI dimerization is related to their broader functional role, particularly in protein trafficking. Results open new avenues for future research to explore the full extent of PSI dimerization and its implications in plant cellular processes.
