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Publications de l’équipe
Imagerie spatio-temporelle de la dynamique des organelles et des
endomembranes
Année de publication : 2002
Ray Mc Dermott, Umit Ziylan, Danièle Spehner, Huguette Bausinger, Dan Lipsker, Mieke
Mommaas, Jean-Pierre Cazenave, Graça Raposo, Bruno Goud, Henri de la Salle, Jean Salamero,
Daniel Hanau (2002 Jan 26)
Birbeck granules are subdomains of endosomal recycling compartment in
human epidermal Langerhans cells, which form where Langerin accumulates.
Molecular biology of the cell : 317-35
Résumé
Birbeck granules are unusual rod-shaped structures specific to epidermal Langerhans cells,
whose origin and function remain undetermined. We investigated the intracellular location
and fate of Langerin, a protein implicated in Birbeck granule biogenesis, in human epidermal
Langerhans cells. In the steady state, Langerin is predominantly found in the endosomal
recycling compartment and in Birbeck granules. Langerin internalizes by classical receptormediated endocytosis and the first Birbeck granules accessible to endocytosed Langerin are
those connected to recycling endosomes in the pericentriolar area, where Langerin
accumulates. Drug-induced inhibition of endocytosis results in the appearance of abundant
open-ended Birbeck granule-like structures appended to the plasma membrane, whereas
inhibition of recycling induces Birbeck granules to merge with a tubular endosomal network.
In mature Langerhans cells, Langerin traffic is abolished and the loss of internal Langerin is
associated with a concomitant depletion of Birbeck granules. Our results demonstrate an
exchange of Langerin between early endosomal compartments and the plasma membrane,
with dynamic retention in the endosomal recycling compartment. They show that Birbeck
granules are not endocytotic structures, rather they are subdomains of the endosomal
recycling compartment that form where Langerin accumulates. Finally, our results implicate
ADP-ribosylation factor proteins in Langerin trafficking and the exchange between Birbeck
granules and other endosomal membranes.
Dan Lipsker, Umit Ziylan, Danièle Spehner, Fabienne Proamer, Huguette Bausinger, Pascale
Jeannin, Jean Salamero, Alain Bohbot, Jean-Pierre Cazenave, Robert Drillien, Yves Delneste,
Daniel Hanau, Henri de la Salle (2002 Jan 25)
Heat shock proteins 70 and 60 share common receptors which are expressed on
human monocyte-derived but not epidermal dendritic cells.
European journal of immunology : 322-32
Résumé
Priming of CTL by means of heat shock proteins (hsp) is dependent on antigen-presenting
cells (APC), which present the hsp-associated peptides, via their cell surface MHC class I
molecules, toCD8(+) T cells. It has not yet been established how human (hu) hsp70 interacts
with the major (hu)APC, the dendritic cells (DC). Here we show that (hu)hsp70 is specifically
internalized intoCD14(-), Toll-like receptor 4(-) monocyte-derived (hu)DC by receptormediated endocytosis. We further demonstrate that (hu)hsp70 and (hu)hsp60 share the
INSTITUT CURIE, 20 rue d’Ulm, 75248 Paris Cedex 05, France | 1
Publications de l’équipe
Imagerie spatio-temporelle de la dynamique des organelles et des
endomembranes
same receptors on (hu)monocyte-derived DC. Both molecules as well as MHC class I
molecules are spontaneously internalized and reach the MHC class II-enriched
compartments. Finally, freshly isolated (hu) epidermal Langerhans cells (LC), the DC of the
skin, as well as CD34(+)-derived LC do not bind hsp60 or hsp70. Given the likely importance
of the internalization of hsp70 by APC in the induction of the immune responses, the finding
that hsp60 and hsp70 are internalized through the same receptor(s) may explain why
microbial hsp60 represents a major T cell antigen. This may rationalize the use of microbial
hsp60 to prime immune responses against microbes. The lack of hsp60/70 receptors on
epidermal LC raises the crucial question as to whether absence of priming of the skin and
mucosal immune systems by hsp-polypeptide complexes could account for some tissuespecific diseases. This work also points to a potential advantage of using monocyte-derived
DC in human immunotherapeutic applications of hsp60/70.
Année de publication : 2001
Isabelle Le Blanc, Vincent Blot, Isabelle Bouchaert, Jean Salamero, Bruno Goud, Arielle R
Rosenberg, Marie-Christine Dokhélar (2001 Dec 26)
Intracellular distribution of human T-cell leukemia virus type 1 Gag proteins is
independent of interaction with intracellular membranes.
Journal of virology : 905-11
Résumé
Retrovirus Gag proteins are synthesized on free ribosomes, and are sufficient to govern the
assembly and release of virus particles. Like type C retroviruses, human T-cell leukemia virus
type 1 (HTLV-1) assembles and buds at the plasma membrane. After immunofluorescence
staining, HTLV-1 Gag proteins appear as punctuated intracellular clusters, which suggests
that they are associated either with intracellular membranes or with the plasma membrane.
However, colocalization experiments using a panel of markers demonstrated that Gag
proteins were not associated with the membranes involved in the secretory or endocytosis
pathway. Small amounts of Gag proteins were detected at the plasma membrane and
colocalized with the envelope glycoproteins. Moreover, Gag proteins were excluded from
streptolysin-O permeabilized cells and in this respect behaved like cytoplasmic proteins. This
suggests that the trafficking of HTLV-1 Gag proteins through the cytoplasm of the host cell is
independent of any cell membrane system.
Année de publication : 2014
Sofia Traikov, Christoph Stange, Thomas Wassmer, Perrine Paul-Gilloteaux, Jean Salamero, Graça
Raposo, Bernard Hoflack (1970 Jan 1)
Septin6 and Septin7 GTP binding proteins regulate AP-3- and ESCRT-dependent
multivesicular body biogenesis.
PloS one : e109372 : DOI : 10.1371/journal.pone.0109372
INSTITUT CURIE, 20 rue d’Ulm, 75248 Paris Cedex 05, France | 2
Publications de l’équipe
Imagerie spatio-temporelle de la dynamique des organelles et des
endomembranes
Résumé
Septins (SEPTs) form a family of GTP-binding proteins implicated in cytoskeleton and
membrane organization, cell division and host/pathogen interactions. The precise function of
many family members remains elusive. We show that SEPT6 and SEPT7 complexes bound to
F-actin regulate protein sorting during multivesicular body (MVB) biogenesis. These
complexes bind AP-3, an adapter complex sorting cargos destined to remain in outer
membranes of maturing endosomes, modulate AP-3 membrane interactions and the motility
of AP-3-positive endosomes. These SEPT-AP interactions also influence the membrane
interaction of ESCRT (endosomal-sorting complex required for transport)-I, which selects
ubiquitinated cargos for degradation inside MVBs. Whereas our findings demonstrate that
SEPT6 and SEPT7 function in the spatial, temporal organization of AP-3- and ESCRT-coated
membrane domains, they uncover an unsuspected coordination of these sorting machineries
during MVB biogenesis. This requires the E3 ubiquitin ligase LRSAM1, an AP-3 interactor
regulating ESCRT-I sorting activity and whose mutations are linked with Charcot-Marie-Tooth
neuropathies.
INSTITUT CURIE, 20 rue d’Ulm, 75248 Paris Cedex 05, France | 3