Group leader : Yohann Boutté, researcher CNRS.

Yohann Boutté did his PhD thesis at CNRS Gif-sur-Yvette under the supervision of Béatrice Satiat-Jeunemaitre (2002-2005), he did two successive post-docs in Sweden, at the Umeå Plant Science Center (UPSC), under the supervision of Markus Grebe (2006-2010) and Rishi Bhalerao (2010-2012). He is a CNRS researcher since 2012 and started his own independent group in 2016.

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Group member:

P. Laquel (CR),M. Hook (PR) L. Fougère (PhD), M. Montrazi (PhD)

Fundings:

Summary

To understand how multi-cellular organisms regulate their growth, and how molecular and cellular mechanisms coordinate tissue and whole organism morphogenesis, I am using higher plants as model system. Higher plants are multi-cellular organisms able to respond and quickly adapt to their environment. This flexibility is in large part due to their ability to modulate the pattern of their body plan and to generate organs throughout the entire life span. This unique property makes plants very convenient models to study morphogenesis and underlying subcellular mechanisms. At the subcellular level, the highly-compartmentalized intracellular membrane system of eukaryotic cells is a basis for multicellular organisms to differentiate function within a tissue and built-up organs in a coordinated way. In eukaryotic cells, a main sorting station for proteins and lipids is the membrane network called trans-Golgi network (TGN) which in plants is clearly discernible at proximity of the trans-most citernae of the Golgi apparatus, allowing easy use of imaging techniques.

In plants, unlike animal TGNs, at least two populations of TGN are observed, one is associated to the Golgi apparatus and one is independent from it as TGNs detach from the Golgi apparatus to form a highly dynamic Golgi-independent structure. This highly dynamic TGN can undergo homotypic fusion as mammalian Early Endosomes (EEs) and can associate transiently with Golgi apparatus, similarly to what is found for EEs and TGN in mammalian cells. Plants have no EEs as described in animals, and endocytic vesicles converge directly to the TGN, where endocytic cargoes are sorted for recycling and/or degradation. Additionally to its EE function, TGN of plants dispatches proteins and components of the extracellular matrix into multiple secretory pathways, including these involved in cell elongation and cell division. Overall, our knowledge on plant TGN, how it receives and sorts cargoes and participates in polar protein sorting is still largely enigmatic and is likely to bear little resemblance with the well-defined animal trafficking systems. It is however a real challenge to unravel the complexity of molecular mechanisms acting at TGN considering the multiple cellular processes regulated by TGN. Beside proteins, numerous studies have showed that lipids are strongly involved in membrane dynamics.

Previously, we have shown that the length of the acyl chain of plant sphingolipids is critical in polar secretory sorting of the auxin efflux carrier PIN2 from TGN to the apical membrane of root epidermal cells (Wattelet-Boyer et al., 2016). We are now aiming at deciphering sphingolipid-dependent mechanisms acting at TGN that would be potentially involved in secretory sorting of proteins to polar domains of the plasma membrane. We are using state-of-the-art quantitative proteomics and lipidomics on immuno-purified intact TGN sub-domains to identify these mechanisms in combination with high-resolution confocal imaging in live cells to reveal the impact of sphingolipids in Golgi generation and TGN dynamics.

Selected articles:

• Ito Y^#, Esnay N^#, Platre M, Noack L, Menzel W, Claverol S, Moreau P, Jaillais Y, Boutté Y*. Sphingolipids mediate polar sorting of PIN2 through phosphoinositide consumption at the trans-Golgi Network. Nature Communications. 
• Mamode Cassim A, Gouguet P, Gronnier J, Laurent N, Germain V, Grison M, Boutté Y, Gerbeau-Pissot P, Simon-Plas F, Mongrand S. Plant lipids: Key players of plasma membrane organization and function. Prog Lipid Res. 2018 Nov 19;73:1-27.
• Ito Y^#, Grison M^#,*, Esnay N, Fouillen L, Boutté Y*. (2020). Immuno-purification of intact endosomal compartments for lipid analyses in Arabidopsis. Methods in Mol Biol., 2177:119-141.
• Boutté Y*, Jaillais Y*. (2020). Metabolic cellular communications: feeback mechanisms between membrane lipid homeostasis and plant development. Developmental Cell, 2:S1534-5807(20)30394-4.
• Trinh DC, Lavenus J, Goh T, Boutté Y, Drogue Q, Vaissayre V, Tellier F, Lucas M, Voß U, Gantet P, Faure JD, Dussert S, Fukaki H, Bennett MJ, Laplaze L, Guyomarc’h S. (2019). PUCHI regulates very long chain fatty acid biosynthesis during lateral root and callus formation. Proc. Natl. Acad. Sci. U S A., 116(28):14325-14330
• Gendre D, Baral A, Dang X, Esnay N, Boutté Y, Stanislas T, Vain T, Claverol S, Gustavsson A, Lin D, Grebe M, Bhalerao RP. (2019). Rho-of-plant activated root hair formation requires Arabidopsis YIP4a/b gene function.Development, 146(5). pii: dev168559.
• Jonsson K, Boutté Y, Singh RK, Gendre D, Bhalerao RP. Ethylene Regulates Differential Growth via BIG ARF-GEF-Dependent Post-Golgi Secretory Trafficking in Arabidopsis. Plant Cell. 2017 May 29(5):1039-1052.
• Wattelet-Boyer V, Brocard L, Jonsson K, Esnay N, Joubès J, Domergue F, Mongrand S, Raikhel N, Bhalerao RP, Moreau P, Boutté Y*. Enrichment of hydroxylated C24- and C26-acyl-chain sphingolipids mediates PIN2 apical sorting at trans-Golgi network subdomains. Nat Commun. 2016 Sep 29;7:12788.

Collaborations:

• Yvon Jallais, Cell Signalling Lab, ENS Lyon – France
• Laurent Laplaze and Soazig Guyomarc’h, ERD Montpellier – France
• Rishikesh Bhalerao, Umeå Plant Science Center – Sweden
• Tomohiro Uemura, the University of Tokyo – Japan
• Jürgen Kleine-Vehn, University of Natural Ressources and Life Sciences, Vienna – Austria