PMID- 20458337 OWN - NLM STAT- MEDLINE DCOM- 20110614 LR - 20220310 IS - 1440-1711 (Electronic) IS - 0818-9641 (Linking) VI - 88 IP - 8 DP - 2010 Nov-Dec TI - MHC class II-associated proteins in B-cell exosomes and potential functional implications for exosome biogenesis. PG - 851-6 LID - 10.1038/icb.2010.64 [doi] AB - Professional antigen-presenting cells secrete major histocompatibility complex class II (MHC II) carrying exosomes with unclear physiological function(s). Exosomes are first generated as the intraluminal vesicles (ILVs) of a specific type of multivesicular body, and are then secreted by fusion of this compartment with the plasma membrane. We have previously shown that in contrast to the sorting of MHC II at lysosomally targeted multivesicular bodies, sorting of MHC II into exosomes does not rely on MHC II ubiquitination. In search for proteins that drive the incorporation of MHC II into exosomes or functionally discriminate exosomal from plasma membrane MHC II, we first analyzed the total proteome of highly purified B cell-derived exosomes using sensitive and accurate mass spectrometry (MS), and identified 539 proteins, including known and not previously identified constituents. Using quantitative MS, we then identified a small subset of proteins that were specifically co-immunoprecipitated with MHC II from detergent-solubilized exosomes. These include HSC71, HSP90, 14-3-3varepsilon, CD20 and pyruvate kinase type M2 (PKM2), and we speculate on the functionality of their interaction with exosomal MHC II. FAU - Buschow, Sonja I AU - Buschow SI AD - Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine and Institute of Biomembranes, Utrecht University, Utrecht, The Netherlands. FAU - van Balkom, Bas W M AU - van Balkom BW FAU - Aalberts, Marian AU - Aalberts M FAU - Heck, Albert J R AU - Heck AJ FAU - Wauben, Marca AU - Wauben M FAU - Stoorvogel, Willem AU - Stoorvogel W LA - eng PT - Journal Article DEP - 20100511 PL - United States TA - Immunol Cell Biol JT - Immunology and cell biology JID - 8706300 RN - 0 (14-3-3 Proteins) RN - 0 (Antigens, CD20) RN - 0 (HSC70 Heat-Shock Proteins) RN - 0 (HSP90 Heat-Shock Proteins) RN - 0 (HSPA8 protein, human) RN - 0 (Histocompatibility Antigens Class II) RN - EC 2.7.1.40 (Pyruvate Kinase) SB - IM MH - 14-3-3 Proteins/metabolism MH - Antigens, CD20/metabolism MH - B-Lymphocytes/cytology/immunology/*metabolism MH - Cell Fractionation MH - Cell Line, Transformed MH - *Exocytosis/immunology MH - Exosomes/*metabolism MH - HSC70 Heat-Shock Proteins/metabolism MH - HSP90 Heat-Shock Proteins/metabolism MH - Histocompatibility Antigens Class II/*metabolism MH - Humans MH - Mass Spectrometry MH - Multivesicular Bodies/*metabolism MH - Pyruvate Kinase/metabolism EDAT- 2010/05/12 06:00 MHDA- 2011/06/15 06:00 CRDT- 2010/05/12 06:00 PHST- 2010/05/12 06:00 [entrez] PHST- 2010/05/12 06:00 [pubmed] PHST- 2011/06/15 06:00 [medline] AID - icb201064 [pii] AID - 10.1038/icb.2010.64 [doi] PST - ppublish SO - Immunol Cell Biol. 2010 Nov-Dec;88(8):851-6. doi: 10.1038/icb.2010.64. Epub 2010 May 11.