R.W. Wubbolts

Publications (7)0 Total impact

• Article: Exosomes contain ubiquitinated proteins.

  S.I. Buschow, J.M. Liefhebber, R.W. Wubbolts, W. Stoorvogel
• Article: Newly synthesized and not endosomally stored MHC class II is used for antigen presentation by dendritic cells at inflammatory conditions.

  A.G. ten Broeke, G. van Niel, M.H.M. Wauben, R.W. Wubbolts, W. Stoorvogel
• Article: Dendritic cells regulate exposure of MHC Class II at their plasma membrane by oligoubiquitination

  G.C.V. van Niel, R.W. Wubbolts, A.G. ten Broeke, S.I. Buschow, F A Ossendorp, C.J.M. Melief, G Raposo, B.W.M. van Balkom, W. Stoorvogel
• Article: Proteomic and biochemical analyses of human B cell-derived exosomes

  R.W. Wubbolts, R.S. Leckie, P. Veenhuizen, G Schwarzmann, W. Moebius, J. Hoernschemeyer, J W Slot, H J Geuze, W. Stoorvogel
• Article: Degradation of MHC class II associated invariant chain in dendritic cells is not developmentally regulated.

  A.G. ten Broeke, A.M. de Graaff, W. Stoorvogel, R.W. Wubbolts
• Article: Trafficking of MHC Class II in dendritic cells is dependent on but not regulated by degradation of its associated invariant chain.

  A.G. ten Broeke, A.M. de Graaff, M.H.M. Wauben, W. Stoorvogel, R.W. Wubbolts
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  ABSTRACT: In dendritic cells (DC), newly synthesized MHCII is directed to endosomes by its associated invariant chain (Ii). Here, Ii is degraded after which MHCII is loaded with peptides. In immature DC, ubiquitination of peptideloaded MHCII drives its sorting to lysosomes for degradation. Ubiquitination of MHCII is strongly reduced in response to inflammatory stimuli, resulting in increased expression of MHCII at the plasma membrane. Whether surface exposure of MHCII is also regulated during DC maturation by changing the rate of Ii degradation remained unresolved by conflicting results in the literature. We here pinpoint experimental problems that have contributed to these controversies and demonstrate that immature and mature DC degrade Ii equally efficient at proper culture conditions. Only when DC were cultured in glutamine containing media, endosome acidification and Ii degradation were restricted in immature DC and enhanced in response to lipopolysaccharide (LPS). These effects are caused by ammonia, a glutamine decomposition product. This artificial behavior could be prevented by culturing DC in media containing a stable dipeptide as glutamine source. We conclude that Ii degradation is a prerequisite for but not a rate limiting step in MHCII processing.
• Article: MHC II in dendritic cells is targeted to lysosomes or T Cell-Induced exosomes via distinct multivesicular body pathways

  S.I. Buschow, E.N.M. Nolte-'t Hoen, Guillaume van Niel, M.S. Pols, A.G. ten Broeke, Marjolein Lauwen, Ferry Ossendorp, C.J.M. Melief, Graça Raposo, R.W. Wubbolts, M.H.M. Wauben, W. Stoorvogel
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  ABSTRACT: Dendritic cells (DCs) express major histocompatibility complex class II (MHC II) to present peptide antigens to T cells. In immature DCs, which bear low cell surface levels of MHC II, peptide-loaded MHC II is ubiquitinated. Ubiquitination drives the endocytosis and sorting ofMHC II to the luminal vesicles of multivesicular bodies (MVBs) for lysosomal degradation. Ubiquitination of MHC II is abrogated in activated DCs, resulting in an increased cell surface expression. We here provide evidence for an alternativeMVB sorting mechanism forMHCII in antigenloaded DCs, which is triggered by cognately interacting antigen-specific CD4+ T cells. At these conditions, DCs generate MVBs with MHC II and CD9 carrying luminal vesicles that are secreted as exosomes and transferred to the interacting T cells. Sorting of MHC II into exosomes was, in contrast to lysosomal targeting, independent of MHC II ubiquitination but rather correlated with its incorporation into CD9 containing detergent-resistant membranes. Together, these data indicate two distinct MVB pathways: one for lysosomal targeting and the other for exosome secretion.