Éditeur(s) : HAL CCSD Portland Press
Résumé : International audience
ISSN: 0143-5221

hal-01678951
https://hal.univ-antilles.fr/hal-01678951
DOI : 10.1042/CS20150461

Éditeur(s) : HAL CCSD Portland Press
Résumé : International audience
Lutheran (Lu) blood group and Basal Cell Adhesion Molecule (BCAM) antigens both reside on two glycoprotein (gp) isoforms, Lu and Lu(v13), that differ by the size of their cytoplasmic tail. They are receptors of laminin-10/11 and are expressed in red blood cells (RBCs), epithelial cells of multiple tissues and vascular endothelial cells. To gain more insights into the biological function of Lu/BCAM gps, we looked for potential partners of their cytoplasmic tail. We isolated Ubc9 (Ubiquitin-conjugating enzyme 9) protein by screening a human kidney library using the yeast two-hybrid system. Lu/Ubc9 interaction was validated by GST pull-down and co-immunoprecipitation experiments. Endogenous Ubc9 formed a complex with endogenous or recombinant Lu gp in A498 and MDCK epithelial cells, respectively. Substitution of lysine 585 by alanine in the Lu gp, abolished in vitro and ex vivo interaction of Lu gp with Ubc9 protein. Lu K585A mutant transfected in MDCK cells exhibited a normal basolateral membrane expression but was overexpressed at the surface of polarized MDCK cells as compared to wild-type Lu. Pulse-chase experiments showed extended half-life of Lu K585A gp at the plasma membrane, suggesting an impaired endocytosis of this mutant leading to protein accumulation at the membrane. Furthermore, we showed that the ability of MDCK-Lu K585A cells to spread on immobilized laminin was dramatically decreased. Our data supports a physiological role for the direct interaction between Lu gp and Ubc9 protein, and reveals a role for this enzyme in regulating the stability of Lu gp at the cell membrane.
ISSN: 0264-6021

hal-00478614
https://hal.archives-ouvertes.fr/hal-00478614
https://hal.archives-ouvertes.fr/hal-00478614/document
https://hal.archives-ouvertes.fr/hal-00478614/file/PEER_stage2_10.1042%252FBJ20060861.pdf
DOI : 10.1042/BJ20060861

Éditeur(s) : HAL CCSD Portland Press
Résumé : International audience
CP12 is a small chloroplastic protein involved in the Calvin cycle that was shown to bind copper, a metal ion involved in modulation of its transition from reduced to oxidized state. In order to describe CP12 copper binding properties, copper-IMAC experiments and site-directed mutagenesis based on computational modeling, were coupled to top-down mass spectrometry (ESI-MS and MSMS). Copper-IMAC experiments allowed the primary characterization of mutation effects upon copper binding. Top-down MSMS experiments carried out under non-denaturing conditions on wild-type and mutant CP12/Cu2+ complexes then allowed fragment ions specifically liganding the copper ion to be determined. Comparison of MSMS datasets defined three regions involved in metal ion binding: residues D16 to D23, D38 to K50 and D70 to E76, with the two first regions containing selected residues for mutation. These data confirmed that copper ligands involved glutamic and aspartic residues in contrast to typical protein copper chelators. We propose that copper might play a role in regulation of CP12 biological activity.
ISSN: 0264-6021

hal-00479106
https://hal.archives-ouvertes.fr/hal-00479106
https://hal.archives-ouvertes.fr/hal-00479106/document
https://hal.archives-ouvertes.fr/hal-00479106/file/PEER_stage2_10.1042%252FBJ20082004.pdf
DOI : 10.1042/BJ20082004

Éditeur(s) : HAL CCSD Portland Press
Résumé : International audience
For cellular fitness and survival, gene expression levels need to be regulated in response to a wealth of cellular and environmental signals. TFs (transcription factors) execute a large part of this regulation by interacting with the basal transcription machinery at promoter regions. Archaea are characterized by a simplified eukaryote-like basal transcription machinery and bacteria-type TFs, which convert sequence information into a gene expression output according to cis-regulatory rules. In the present review, we discuss the current state of knowledge about these rules in archaeal systems, ranging from DNA-binding specificities and operator architecture to regulatory mechanisms.
ISSN: 0300-5127

hal-01542965
http://hal.upmc.fr/hal-01542965
DOI : 10.1042/BST20120312