Conformation-dependent partitioning of yeast nutrient transporters into starvation-protective membrane domains.
Gournas C, Gkionis S, Carquin M, Twyffels L, Tyteca D, André B.
Proc Natl Acad Sci U S A. 2018 Mar 20. pii: 201719462. doi: 10.1073/pnas.1719462115
The plasma membrane of eukaryotic cells is compartmentalized into domains enriched in specific lipids and proteins. However, our understanding of the mechanisms and functions of this lateral segregation remains incomplete. In this study led by Christos Gournas from the Molecular Physiology of the Cell lab (ULB), we report that the clustering of the yeast Can1 arginine transporter into domains is dictated by its conformation and requires sustained biogenesis of complex sphingolipids. Furthermore, this clustering confers to Can1 and other transporters protection from ubiquit-independent endocytosis. Under nutrient starvation conditions, this protective role is reinforced, thereby allowing cells to preserve a fraction of their nutrient transporters from bulk endocytosis and to more efficiently resume growth when replenishing compounds are available. Our study reveals nutrient-regulated protection from endocytosis as an important role for protein partitioning into membrane domains.The images above were acquired on the CMMI’s Zeiss LSM710, using its Airy Scan module. Shown are surface section of an art1Δ bul1/2Δ gap1Δ can1Δ PIL1-mCherry yeast strain expressing Can1-GFP, Can1(T180R)-GFP, or Can1(S176N,T456S)-GFP. Can1(T180R) is a loss-of-function mutant of Can1 that is unable to bind Arg. Can1(S176N,T456S) is a mutant converted into a Lys-scpecific transporter. Taken together with additional data in the article, these observations demonstrated that substrate transport abolishes Can1 EMC clustering. Conditions and quantifications (n = 32–42) are as in B. ***P < 0.001; ns, nonsignificant, P > 0.05. (Scale bar: 2 μm.).
New Folate-Grafted Chitosan Derivative To Improve Delivery of Paclitaxel-Loaded Solid Lipid Nanoparticles for Lung Tumor Therapy by Inhalation.
Rosière R, Van Woensel M, Gelbcke M, Mathieu V, Hecq J, Mathivet T, Vermeersch M, Van Antwerpen P, Amighi K, Wauthoz N.
Mol Pharm. 2018 Mar 5;15(3):899-910. doi: 10.1021/acs.molpharmaceut.7b00846. Epub 2018 Jan 30
Inhaled chemotherapy for the treatment of lung tumors requires that drug delivery systems improve selectivity
for cancer cells and tumor penetration and allow sufficient lung residence. The study led by Rémi Rosière from the Laboratoire de Pharmacie Galénique et Biopharmacie demonstrates the positive impact of using coated “solid lipid nanoparticles” on the delivery of paclitaxel by inhalation.The CMMI’s contribution to the study was to image solid lipid nanoparticles by transmission electron microscopy. The figure above compares the morphology of paclitaxel-loaded solid lipid nanoparticles with or without F-PEG-HTCC coating. Scale bar: 200 nm.
A prospective clinical study of the implications of IL-8 in the diagnosis, aggressiveness and prognosis of prostate cancer.
Roumeguère T, Legrand F, Rassy EE, Kaitouni MI, Albisinni S, Rousseau A, Vanhaeverbeek M, Rorive S, Decaestecker C, Debeir O, Boudjeltia KZ, Aoun F.
Future Sci OA. 2017 Nov 15;4(2):FSO266. doi: 10.4155/fsoa-2017-0084. eCollection 2018 Feb.
In this collaborative clinical study, researchers from three hospitals (Erasme hospital in Brussels, André Vésale Hospital in Charleroi and Hôtel Dieu de France Hospital in Beirut) as well as from the CMMI investigate the relationship between the IL-8 cytokine and prostate cancer. They conclude that IL-8 serum level is not a significant predictor of diagnosis, aggressiveness or prognosis of prostate cancer.