First publication from our lab: Microbial Effector Proteins – A Journey through the Proteolytic Landscape

Summary: In the evolutionary arms race between pathogens and plants, pathogens evolved effector molecules that they secrete into the host to subvert plant cellular responses in a process termed the effector-targeted pathway (ETP). During recent years the repertoire of ETPs has increased and mounting evidence indicates that the proteasome and autophagy pathways are central hubs of microbial effectors. Both degradation pathways are implicated in a broad array of cellular responses and thus constitute an attractive target for effector proteins to have a broader impact on the host. In this article we first summarize recent findings on how effectors from various pathogens modulate proteolytic pathways and then provide a network analysis of established effector targets implicated in proteolytic degradation machineries. With this network we emphasize the idea that effectors targeting proteolytic degradation pathways will affect the protein synthesis-transport and degradation triangle. We put in perspective that, in utilizing the effector diversity of microbes, we produce excellent tools to study diverse cellular pathways and their possible interplay with each other.

In this opinion article, published in Trends in Microbiology, we are suggesting the idea that effectors targeting plant proteostasis will have a broader impact on the host cell. Suppressing or activating distinct degradation machineries will have an impact on other cellular machineries such as protein transport and/or translation, and we therefore propose a model in which effector proteins affect the triangle model of protein synthesis, transport, and degradation.

The idea of writing this article developed during a coffee break in our institute one year ago. We did not want to write another review on effectors or autophagy as there are already so many excellent reviews covering these topics. By providing a “network” analysis of microbial effectors and known targets we tried to highlight and reveal novel connections that might be interesting for future studies in the effector community. With this small piece of work you you will also find many hints what we are currently working on and plan to work on in the future. Effectors are fantastic probes to elucidate pathways within an organism, leading to unknown interplays and connections. 

And finally, huge thanks to my fantastic team members Gautier Langin and Paul Gouguet who made this all possible. We are also grateful to Trends in Microbiology for giving us this unique chance to contribute this work! Enjoy reading our article-it is open access! Here is the link: 

https://www.sciencedirect.com/science/article/pii/S0966842X20300469#f0005

The Üstün Lab Year End Résumé

2019 is over and with it a decade in which many things happened in all of our lives. During these 10 years many discoveries were made, from CRISPR/Cas9, single cell RNAseq to the NLR resistosome, that changed our scientific views and opportunities to tackle challenging questions. It also enabled young scientists to build-up their own labs that will for sure change the research landscape in the next decade. This is our very own year-end summary with all what  we experienced in 2019.

 

January: Nothing special happened during this month. Slowly coming back from the Christmas vacation and making everything ready for the upcoming arrivals were certainly on the agenda during this month. Ah yeah, Suayb finally gets his office and is on an undercover mission at the COS party in Heidelberg (thanks to Alyona) 🙂

Our lab motto 🙂

February: Paul arrives in Tübingen in our team and starts his postdoctoral research on the bacterial effector-driven interplay between vesicle trafficking and autophagy. He made a huge impact from the beginning, participating in seminars, asking excellent questions and also socializing with many other members of the ZMBP. Team leader Suayib went to the yearly “Molecular Biology of Plants” conference in Dabringhausen and presented his work on the interplay between the proteasome and autophagy during bacterial infection and his future plans for the Üstün Lab.

March: Our first PhD student Gautier arrives in March and starts the SFB1101 funded project on the proteasome regulation during plant immunity. Gautier quickly integrates into the lab and also immediately takes part in our RegioPlantScience Meeting in Hohenheim. Paul is also giving his first progress seminar at the 6th floor. Finally, our small team is complete!

April: Suayb takes part in the ZMBP Group Leader Retreat in Bad Urach. Pia Lutz, master student at the ZMBP, starts her lab rotation in our lab. She worked on E3 ligases that probably mediate the proteaphagy response during plant immunity. We had a great time with her, and she made substantial findings that will certainly help us in the future.

Margot is generating her material.

May: Suayb participates in the leadership workshop offered by the ZWM and covered by the DFG. This is certainly something that all junior but also quite a few senior group leaders should consider as it really provides useful information how to lead a team. Suayb also kick starts the preprint club at the ZMBP, initiated by Mayank Chugh (at this time PhD student at the Cellular Nanoscience). Mid may, Margot Raffeiner from the Börnke Lab (IGZ, Grossbeeren) joins our team for more than 2 weeks to perform in vitro ubiquitination assays and pulldown experiments to identify posttranslational modifications as well as novel interactions partners of her candidate proteins. We had a very intense and fun time during these two weeks in the lab and Margot made a lot of new friends at the ZMBP. We hope she’ll join for some additional experiments in 2020!

Ubiquitin Blot from the  course.

June: The Üstün Lab organized and conducted its
first master course in “Function and analysis of proteolytic degradation pathways”. Thanks to Gautier and Paul everything worked out and we had a great time during these two weeks with our students. It was a great experience and we hope to get more students next year to bring them closer to the plant proteostasis topic.

Suayb giving a talk in Glasgow.

July: This month was definitely one of the busiest during the whole year. We submitted our full proposal for the SFB1101. Suayb went to the Emmy Noether Meeting in Potsdam, organized by the DFG and directly continued networking at the 18th international workshop on plant membrane biology in Glasgow. He presented Paul’s work on the interplay between vesicle trafficking and plant immunity. Glasgow was also the stage for the Congress on Molecular Plant-Microbe Interactions (MPMI 2019), where Paul and Gautier had the chance to present their projects during the poster sessions. It was a great experience for everyone, a good opportunity to establish and/or strengthen ongoing collaborations, as well as perfect occasion to meet old friends!

August: It’s vacation time! By the end of the month Gautier participates in the annual PhD Retreat of the ZMBP and presents his project in form of a chalk talk.

Gautier is giving a chalk talk during the PhD retreat.

Group Picture at Conference Dinner in Freiburg.

September: Our conference marathon is still not finished as our whole team is presenting at the “International Conference of Plant Proteostasis” in beautiful Freiburg. This specialized meeting is a full success creating many new collaborations and ideas for our research. Being part of the “PlantProteostasis” community will provide our group with many opportunities in the future. We are also celebrated the 20th anniversary of the ZMBP, with an impressive line-up of speakers (current and former ZMBP members as well as invited speakers). It’s a privilege to be part of this great community! For Gautier it was a busy month full of “conferencing” as he participated at the 4th summer academy organized by PhD students at ZMBP!

October: Suayb is invited to INRA Toulouse by Laurent Noël for a PhD thesis committee meeting and also gives a seminar on the role of Autophagy during plant-microbe interactions. Certainly, this was one of the most memorable days during 2020 due to the great hospitality and also science taking place in Toulouse! After Toulouse, Gautier and Suayb participate in the SFB1101 retreat in Heidelberg. Gautier is talks about his findings on the regulation of the proteasome and we are able to strengthen our network with labs from COS Heidelberg, ZMBP Tübingen as well as University of Hohenheim. At the end of the month all members of The Üstün Lab participate in the bachelor course “Molekulare Genetik der Pflanzen”.

Vacuolar staining of Col-0 roots.

November begins with amazing news: The Üstün Lab secured its first grant (SFB1101) which will enable us to get a new team member in 2020! The Üstün Lab is also starting to write its very first article which deals with microbial effectors and their role in proteolytic degradation. We also said hello to Alyona Minina from COS Heidelberg/SLU Uppsala who was helping us out with some amazing vacuole staining and root imaging. Thanks to Alyona we made a crucial finding in Paul’s project and we are pretty sure that this great collaboration with Alyona will yield to many more exciting findings! This
amazing work week ended with Gautier’s first PhD thesis meeting and a visit of Yasin Dagdas, group leader at GMI Vienna, who is one of Gautier’s thesis committee members. Gautier presented his current progress as well as future directions receiving great feedback by his thesis committee members. For our group Yasin’s visit was a true win as we could establish new collaborations that will hopefully yield exciting findings! This busy month ended with a visit of Jos Schippers, group leader at IPK Gatersleben, whom we hosted for our SFB1101 seminar series at the ZMBP. It was really great to have Jos here in Tübingen and we could establish some future collaborations.

December: This month started with the arrival of two new group members. Ophélie Léger from Toulouse, future PhD student in the group of Thomas Stanislas at ZMBP, joined us as a research assistant for one month. Jia Xuan Leong, master student at the University of Heidelberg is currently doing her lab rotation and working on the project “how a bacterial effector modulates autophagy”. We are really glad to have you all here in our team. Finally, we also started one of our big experiments for 2020: in a great team effort we planted approximately 900 Arabidopsis plants for a huge proteomics experiment. Thanks again to Paul, Gautier, Ophélie and Jia Xuan for their work! Also, during this month, we hosted Marco Trujillo from University of Freiburg for our SFB1101 seminar series. Marco gave an excellent presentation about his past and ongoing work on protein ubiquitination and its role in plant immunity. Our month pretty much ended with our traditional Christmas celebration at the “Schwärzloch” with lots of Glühwein, Lebkuchen and german Christmas dishes! Finally, we also submitted our first manuscript, just before Christmas!

It was a very intense, productive, sometimes tiring and challenging year for our small team. This small break during the years will charge our empty batteries and provide us with energy for new adventures and journeys that we will have to face in 2020. 

The Üstün Lab is wishing everyone a happy new year and a fantastic start in 2020!

PhD Position in Plant-Microbe Interaction and Cell Biology

We are searching for a talented PhD student (f,m,d) to study microbial effector proteins and how they affect autophagy and vacuolar trafficking. More information can be found below in the advertisement. Please send the application via email to suayib.uestuen@zmbp.uni-tuebingen.de The position is available immediately (starting date negotiable) and reviewing of applications will continue until the position is filled.

One year anniversary of the Üstün Lab

Exactly one year ago I was entering the building of the Center for Plant Molecular Biology, the ZMBP in Tübingen. I was humbled, intimidated, excited like a first years’ school kid and full of motivation to start my own lab. Since I started my PhD, I had this dream to become a group leader, to supervise PhD students & Postdocs and to transfer my knowledge and experience to younger people. Finally I achieved this goal, started “the Üstün Lab” without really anticipating how challenging but also rewarding it will be to fulfill this position.

I have to admit the beginning was tough, especially because you face many new administrative tasks and small obstacles that you were not aware of while being a PhD student or Postdoc. Luckily, I had a lot of support from all the people of our floor at the ZMBP and after a couple of months basically everything was settled to start off the lab. Beginning of the year, Paul Gouguet joined our team as a Postdoc and only one month after him I had the excitement to welcome my very first PhD student, Gautier Langin. Finally our small team was there, out in the world of science, trying to discover novel findings. Within these first months we had some failures like non-significant qPCRs, failed clonings, contaminated MS plates or failed crosses. But these were just minor setbacks and looking back I remember our amazing RNAseq data set with a lot of new candidates connecting proteasome regulation with other pathways or novel surprising findings on the interplay between autophagy and vesicle trafficking 🙂 Watching your team members presenting their newest data at progress meetings or symposia is a completely rewarding feeling especially when you see how your team members embrace their projects and grow into them!

During these months we also grew together as a lab, had a lot of fun at our regular beer happy hour at the ZMBP or during small lab outings in lovely Tübingen. I guess that one of this years highlights was that all members of our lab attended the IS-MPMI in Glasgow having an amazing time full of science and other nice activities there.

Overall, it was a very exciting year for the Üstün Lab establishing our little group, starting new journeys and collaborations. I am grateful for my two excellent team members and we hope to expand our team in the near future with a new PhD student. I hope and believe that this next year holds many new findings, surprises and adventures for the Üstün Lab. Stay tuned for more news in the future!

New publication: A remorin interacts with the Pseudomonas T3E HopZ1a & is phosphorylated by the immune-related kinase PBS1

The plasma membrane is at the interface of plant-pathogen interactions and thus many bacterial type-III effector proteins (T3Es) target membrane-associated processes to interfere with immunity. The Pseudomonas syringae T3E HopZ1a is a host cell plasma membrane (PM)-localized effector protein that has several immunity associated host targets but also activates effector triggered immunity (ETI) in resistant backgrounds. Although HopZ1a has been shown to interfere with early defense signaling at the PM, no dedicated plasma membrane-associated HopZ1a target protein has been identified until now. We show here, that HopZ1a interacts with the PM-associated remorin protein NbREM4 from Nicotiana benthamiana in several independent assays. NbREM4 re-localizes to membrane sub-nanodomains after treatment with the bacterial elicitor flg22 and transient overexpression of NbREM4 in N. benthamiana induces the expression of a subset of defense related genes. We can further show that NbREM4 interacts with the immune-related receptor-like cytoplasmic kinase PBS1 and is phosphorylated by PBS1 on several residues in vitro. Thus, we conclude that NbREM4 is associated with early defense signaling at the PM. The possible relevance of the HopZ1a/NbREM4 interaction for HopZ1a virulence and avirulence functions is discussed.

This journey started in 2012 when I was a PhD student in the lab of Frederik Börnke. Philip Albers continued to work on this project during his PhD thesis and it is great to see this paper from the Börnke and Üstün Labs being published in Molecular Plant-Microbe Interaction. Congrats to everyone involved in this story!

Suayib Üstün receives Emmy Noether Funding by the DFG

Suayib Üstün receives the Emmy Noether Funding by the German Research Foundation (DFG) to establish his own independent research group at the Center of Plant Molecular Biology (ZMBP) in Tübingen. He will move to Tübingen in the beginning of September. Stay tuned for news and upcoming job advertisements.