Multivesicular bodies associate with components of miRNA effector complexes and modulate miRNA activity.
In animals, P-bodies or GW-bodies appear to cause the congregation of proteins involved in microRNA (miRNA)-mediated post-transcriptional silencing. The localization of P-bodies does not overlap with that of known organelles and are thus considered independent of lipid bilayers. Nonetheless, an miRNA effector protein, argonaute 2 (AGO2), was initially identified as membrane-associated, and some miRNAs have been found in secreted vesicles (exosomes) that derive from endo-lysosomal compartments called multivesicular bodies (MVBs). Proteins can be sorted in a ubiquitin-dependent manner into MVBs by three heteromeric subcomplexes, collectively termed ESCRT (endosomal sorting complex required for transport), to be further secreted in exosomes and/or degraded by the lysosome. Here we show that GW-bodies containing GW182 and AGO2, two main components of the RNA-induced silencing complex (RISC), are distinct from P-bodies due to their congregation with endosomes and MVBs. Moreover, miRNAs and miRNA-repressible mRNAs are enriched at these cellular membranes, suggesting that endosomes and/or MVBs are sites of miRNA-loaded RISC (miRISC) accumulation and, possibly, action. We further show that purified exosome-like vesicles secreted by MVBs are considerably enriched in GW182, but not P-body components, AGO2 or miRNA-repressible mRNA. Moreover, cells depleted of some ESCRT components show compromised miRNA-mediated gene silencing and over-accumulate GW182, which associates with ubiquitylated proteins. Therefore, GW182, possibly in association with a fraction of miRNA-loaded AGO2, is sorted into MVBs for secretion and/or lysosomal degradation. We propose that this process promotes continuous assembly or disassembly of membrane-associated miRISCs, which is possibly required for miRNA loading or target recognition and subsequent silencing.
Gibbings
Derrick J
DJ
IBMP-CNRS, UPR Université de Strasbourg, France.
Ciaudo
Constance
C
Erhardt
Mathieu
M
Voinnet
Olivier
O
D060565:Argonaute Proteins; D001324:Autoantigens / Q000378:metabolism; D002460:Cell Line; D004722:Endoribonucleases / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism* / Q000648:ultrastructure; D015852:Eukaryotic Initiation Factor-2 / Q000378:metabolism; D055354:Exosomes / Q000378:metabolism / Q000648:ultrastructure; D055785:Gene Knockdown Techniques; D006801:Humans; D035683:MicroRNAs / Q000378:metabolism*; D021381:Protein Transport; D016601:RNA-Binding Proteins; D015534:Trans-Activators / Q000378:metabolism
C466422:AGO2 protein, human; D060565:Argonaute Proteins; D001324:Autoantigens; D015852:Eukaryotic Initiation Factor-2; D035683:MicroRNAs; D016601:RNA-Binding Proteins; C465663:TNRC6A protein, human; D015534:Trans-Activators; D004722:Endoribonucleases; C466279:DCP1A protein, human
Nat Cell Biol. 2008 Dec;10(12):1470-6
19011622
Nat Rev Immunol. 2002 Aug;2(8):569-79
12154376
Nat Struct Mol Biol. 2008 Apr;15(4):346-53
18345015
Clin Exp Immunol. 2006 Mar;143(3):572-84
16487257
PLoS Biol. 2006 Jul;4(7):e210
16756390
Cell. 2007 Mar 23;128(6):1105-18
17382880
Nat Cell Biol. 2005 Dec;7(12):1267-74
16284622
Genes Dev. 2004 Mar 1;18(5):504-11
15014042
Nat Cell Biol. 2009 Sep;11(9):1150-6
19684574
Proteomics. 2005 Nov;5(16):4145-51
16196087
Genes Dev. 2007 Oct 15;21(20):2539-44
17938239
Methods Enzymol. 2007;431:61-81
17923231
Genes Dev. 2007 Oct 15;21(20):2558-70
17901217
Trends Genet. 2003 Jul;19(7):362-5
12850439
J Cell Sci. 2005 Jun 15;118(Pt 12):2625-35
15914539
Traffic. 2005 Dec;6(12):1196-212
16262729
Cell Cycle. 2008 Jun 1;7(11):1545-9
18469529
Nat Cell Biol. 2005 Dec;7(12):1261-6
16284623
J Cell Sci. 1997 Aug;110 ( Pt 16):1867-77
9296387
Nucleic Acids Res. 2007;35(4):1289-300
17267406
J Cell Sci. 2008 Dec 15;121(Pt 24):4134-44
19056672
J Biol Chem. 1998 Jan 23;273(4):2416-23
9442091
Traffic. 2003 Nov;4(11):785-801
14617360
Gynecol Oncol. 2008 Jul;110(1):13-21
18589210
Curr Protoc Mol Biol. 2005 Nov;Chapter 26:Unit 26.4
18265364
Nat Cell Biol. 2007 Jun;9(6):654-9
17486113
Mol Biol Cell. 2006 Aug;17(8):3469-83
16707569
Genes Dev. 2005 Feb 1;19(3):351-61
15687258
Nat Struct Mol Biol. 2007 Oct;14(10):897-903
17891150
J Biol Chem. 1998 Aug 7;273(32):20121-7
9685355
Cell. 2009 Mar 6;136(5):926-38
19269369
Proc Natl Acad Sci U S A. 2008 Apr 29;105(17):6308-13
18434552
J Virol. 2002 Jun;76(12):6185-96
12021352
EMBO Rep. 2007 Nov;8(11):1052-60
17932509
J Cell Biol. 2005 Jun 20;169(6):871-84
15967811
J Biol Chem. 2007 Mar 30;282(13):9591-9599
17276987
Nat Cell Biol. 2005 Jun;7(6):633-6
15908945
J Exp Med. 1996 Mar 1;183(3):1161-72
8642258
Mol Endocrinol. 2007 May;21(5):1132-47
17312270
RNA. 2005 Dec;11(12):1795-802
16314453
Science. 2005 Dec 16;310(5755):1817-21
16308420
RNA. 2006 May;12(5):707-9
16641511
Cell. 2009 Mar 6;136(5):913-25
19269368