References of "Perez-Morga, David"
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See detailSpecific expression and function of inositol 1,4,5-trisphosphate 3-kinase C (ITPKC) in wild type and knock-out mice
Scoumanne, Ariane; Molina Ortiz, Patricia ULg; Monteyne, Daniel et al

in Advances in Biological Regulation (in press)

Inositol 1,4,5-trisphosphate 3-kinase C (ITPKC) is the last identified member of the inositol 1,4,5-trisphosphate 3-kinases family which phosphorylates inositol 1,4,5-trisphosphate into inositol 1,3,4,5 ... [more ▼]

Inositol 1,4,5-trisphosphate 3-kinase C (ITPKC) is the last identified member of the inositol 1,4,5-trisphosphate 3-kinases family which phosphorylates inositol 1,4,5-trisphosphate into inositol 1,3,4,5-tetrakisphosphate. Although expression and function of the two other family members ITPKA and ITPKB are rather well characterized, similar information is lacking for ITPKC. Here, we first defined the expression of Itpkc mRNA and protein in mouse tissues and cells using in situ hybridization and new antibodies. Surprisingly, we found that cells positive for ITPKC in the studied tissues express either a multicilium (tracheal and bronchial epithelia, brain ependymal cells), microvilli forming a brush border (small and large intestine, and kidney proximal tubule cells) or a flagellum (spermatozoa), suggesting a role for ITPKC either in the development or the function of these specialized cellular structures. Given this surprising expression, we then analyzed ITPKC function in multiciliated tracheal epithelial cells and sperm cells using our Itpkc knock-out mouse model. Unfortunately, no significant difference was observed between control and mutant mice for any of the parameters tested, leaving the exact in vivo function of this third Ins(1,4,5)P3 3-kinase still open. [less ▲]

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See detailPoplar-root-knot nematode interaction: a model for perennial woody species
Baldacci-Cresp, Fabien; Sacre, Pierre-Yves ULg; Twyffels, Laure et al

in Molecular Plant-Microbe Interactions [=MPMI] (2016), 29(7), 560-572

Plant root-knot nematode interaction studies are performed on several host plant models. However, even though root-knot nematodes interact with trees, no perennial woody model has been explored so far. We ... [more ▼]

Plant root-knot nematode interaction studies are performed on several host plant models. However, even though root-knot nematodes interact with trees, no perennial woody model has been explored so far. We show here that poplar (Populus tremula x Populus alba) grown in vitro is susceptible to Meloidogyne incognita as this nematode is able to penetrate, to induce feeding sites and to reproduce in poplar roots. As analyzed by Raman spectromicroscopy, the cell walls of the giant cells, with typical characteristics of transfer cell walls, were not lignified and were composed mainly of pectin and cellulose. To better depict the poplar-nematode interaction at the molecular level, a quantitative RT-PCR analysis was performed to study changes in poplar gene expression in galls compared to non-infected roots. Three marker genes, reported for other plant hosts, including expansin A, histone 3.1 and asparagine synthase, were conserved for poplar-nematode interaction. In addition, the down-regulation of four genes coding for enzymes of the lignin biosynthesis pathway was evidenced in galls, suggesting a modification in lignin composition within galls developed in poplar roots. Together, this study shows that poplar is a suitable model host for specific traits of tree-nematode interaction. [less ▲]

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See detailMechanism of Trypanosoma brucei gambiense resistance to human serum.
Uzureau, Pierrick; Uzureau, Sophie; Lecordier, Laurence et al

in Nature (2013), 501(7467), 430-4

The African parasite Trypanosoma brucei gambiense accounts for 97% of human sleeping sickness cases. T. b. gambiense resists the specific human innate immunity acting against several other tsetse-fly ... [more ▼]

The African parasite Trypanosoma brucei gambiense accounts for 97% of human sleeping sickness cases. T. b. gambiense resists the specific human innate immunity acting against several other tsetse-fly-transmitted trypanosome species such as T. b. brucei, the causative agent of nagana disease in cattle. Human immunity to some African trypanosomes is due to two serum complexes designated trypanolytic factors (TLF-1 and -2), which both contain haptoglobin-related protein (HPR) and apolipoprotein LI (APOL1). Whereas HPR association with haemoglobin (Hb) allows TLF-1 binding and uptake via the trypanosome receptor TbHpHbR (ref. 5), TLF-2 enters trypanosomes independently of TbHpHbR (refs 4, 5). APOL1 kills trypanosomes after insertion into endosomal/lysosomal membranes. Here we report that T. b. gambiense resists TLFs via a hydrophobic beta-sheet of the T. b. gambiense-specific glycoprotein (TgsGP), which prevents APOL1 toxicity and induces stiffening of membranes upon interaction with lipids. Two additional features contribute to resistance to TLFs: reduction of sensitivity to APOL1 requiring cysteine protease activity, and TbHpHbR inactivation due to a L210S substitution. According to such a multifactorial defence mechanism, transgenic expression of T. b. brucei TbHpHbR in T. b. gambiense did not cause parasite lysis in normal human serum. However, these transgenic parasites were killed in hypohaptoglobinaemic serum, after high TLF-1 uptake in the absence of haptoglobin (Hp) that competes for Hb and receptor binding. TbHpHbR inactivation preventing high APOL1 loading in hypohaptoglobinaemic serum may have evolved because of the overlapping endemic area of T. b. gambiense infection and malaria, the main cause of haemolysis-induced hypohaptoglobinaemia in western and central Africa. [less ▲]

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See detailINPP5E mutations cause primary cilium signaling defects, ciliary instability and ciliopathies in human and mouse
Jacoby, Monique; Cox, James J.; Gayral, Stéphanie et al

in Nature Genetics (2009), 41

The primary cilium is an antenna-like structure that protrudes from the cell surface of quiescent/differentiated cells and participates in extracellular signal processing1–3. Here, we report that mice ... [more ▼]

The primary cilium is an antenna-like structure that protrudes from the cell surface of quiescent/differentiated cells and participates in extracellular signal processing1–3. Here, we report that mice deficient for the lipid 5-phosphatase Inpp5e develop a multiorgan disorder associated with structural defects of the primary cilium. In ciliated mouse embryonic fibroblasts, Inpp5e is concentrated in the axoneme of the primary cilium. Inpp5e inactivation did not impair ciliary assembly but altered the stability of pre-established cilia after serum addition. Blocking phosphoinositide 3-kinase (PI3K) activity or ciliary platelet-derived growth factor receptor a (PDGFRa) restored ciliary stability. In human INPP5E, we identified a mutation affecting INPP5E ciliary localization and cilium stability in a family with MORM syndrome, a condition related to Bardet-Biedl syndrome. Together, our results show that INPP5E plays an essential role in the primary cilium by controlling ciliary growth factor and PI3K signaling and stability, and highlight the consequences of INPP5E dysfunction. [less ▲]

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See detailApolipoprotein L-1 Promotes Trypanosome Lysis By Forming Pores In Lysosomal Membranes
Perez-Morga, David; Vanhollebeke, Benoit; Paturiaux-Hanocq, Françoise et al

in Science (2005), 309(5733), 469-72

Apolipoprotein L-I is the trypanolytic factor of human serum. Here we show that this protein contains a membrane pore-forming domain functionally similar to that of bacterial colicins, flanked by a ... [more ▼]

Apolipoprotein L-I is the trypanolytic factor of human serum. Here we show that this protein contains a membrane pore-forming domain functionally similar to that of bacterial colicins, flanked by a membrane-addressing domain. In lipid bilayer membranes, apolipoprotein L-I formed anion channels. In Trypanosoma brucei, apolipoprotein L-I was targeted to the lysosomal membrane and triggered depolarization of this membrane, continuous influx of chloride, and subsequent osmotic swelling of the lysosome until the trypanosome lysed. [less ▲]

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