Plants recycle too

23 June 2014

​The story behind the science

For their own wellbeing, cells constantly adjust the composition of their membrane proteins and lipids. New proteins are incorporated, while old proteins get recycled or eliminated by  internalization, a process called endocytosis. The groups of Daniël van Damme and Geert De Jaeger (VIB Department of Plant Systems Biology, UGent) together with the team of Staffan Persson (Max Planck Institute, Golm, Germany) identified a new protein complex that is crucial for endocytosis in plants.

The story goes back a long time. Can you tell us where it started?
Daniël: It started in 2001 with screening for proteins that were recruited to the forming cell plate. One protein accumulated in a T-shape when the growing cell plate made contact with the plasma membrane, therefore we named it TPLATE. Having no clue about its function, we applied various chemicals to interfere with TPLATE’s localization and found a connection with clathrin. Simultaneously, we searched for interactors of TPLATE. Step by step we discovered that TPLATE was involved in clathrinmediated endocytosis and, thanks to the tandemaffinity purification technique used in Geert De Jaeger’s lab, we identified the TPLATE complex, consisting entirely of unknown proteins.

Along the road, you became aware of serious competition in the field. How did you solve this?
During the talk of Clara Sánchez-Rodríguez from the group of Staffan Persson (Max Planck Institute) at the ENPER meeting in Barcelona, it became utterly clear to me that we both independently arrived at the same complex and its function in endocytosis.
When I gave my talk the next day, this also became clear to everyone else. As all experiments performed were complementary, the best option was to combine everything, and we started a very nice collaboration.

Endocytosis is a heavily studied research topic in the biomedical field. Why was the TPLATE complex only discovered now?
Likely because there are no obvious homologs of the TPLATE complex members in yeast or animals. Recently however, the Robinson group in Cambridge did identify a similar complex in the slime mold Dictyostelium and showed that this complex got lost in the lineage leading to yeast and animal cells. It also appears not very active in Dictyostelium, making it very plausible that plants are the only ones that retained a functional TPLATE complex  throughout evolution. The major question now is why.

Only last year 14 PSB papers (four in The Plant Cell, one in Science and one in Cell) were published that used TAP technology. You are guarding a goldmine, Geert!
Geert: Well, the cell itself is a goldmine and we have indeed a great tool on hand for digging. TAP
technology is so powerful because it works in situ, searches proteome-wide and is very specific. The TAP procedure is quite complicated but, having performed about 3000 TAP purifications in total by now, it is fair to say that my team members are world class ‘tappers’. On top of that, we receive excellent mass-spectrometry services from Kris Gevaert’s PEC. If you suddenly discover a whole new protein machine, the goal of unraveling its function is immediately set. And this T-PLATE story is the best example of this.

Gadeyne, Sánchez-Rodríguez et al.
Cell 2014

Back from L to R: Kris Gevaert, Steven Maere and Bernard Cannoot
Middle from L to Rt: Jenny Russinova, Geert Persiau and Eveline Van De Slijke
Front from L to R: Astrid Gadeyne, Daniël Van Damme, Jelle Van Leene and Geert De Jaeger.
© VIB, 2014