title: ASB2 is an Elongin BC-interacting protein that can assemble with Cullin 5 and Rbx1 to reconstitute an E3 ubiquitin ligase complex.
abstract: The ankyrin repeat-containing protein with a suppressor of cytokine signaling box-2 (ASB2) gene was identified as a retinoic acid-response gene and a target of the promyelocytic leukemia-retinoic acid receptor-alpha oncogenic protein characteristic of acute promyelocytic leukemia. Expression of ASB2 in myeloid leukemia cells inhibits growth and promotes commitment, recapitulating an early step known to be critical for differentiation. Here we show that ASB2, by interacting with the Elongin BC complex, can assemble with Cullin5.Rbx1 to form an E3 ubiquitin ligase complex that stimulates polyubiquitination by the E2 ubiquitin-conjugating enzyme Ubc5. This is a first indication that a member of the ASB protein family, ASB2, is a subunit of an ECS (Elongin C-Cullin-SOCS box)-type E3 ubiquitin ligase complex. Altogether, our results strongly suggest that ASB2 targets specific proteins to destruction by the proteasome in leukemia cells that have been induced to differentiate.
authors.affiliation: INSERM, U417, Hôpital Robert Debré, 48 Boulevard Serurier, F-75935 Paris Cedex 19, France.
authors.forename: Mélina L
authors.initials: ML
authors.lastname: Heuzé
authors.forename: Florence C
authors.initials: FC
authors.lastname: Guibal
authors.forename: Charles A
authors.initials: CA
authors.lastname: Banks
authors.forename: Joan W
authors.initials: JW
authors.lastname: Conaway
authors.forename: Ronald C
authors.initials: RC
authors.lastname: Conaway
authors.forename: Yvon E
authors.initials: YE
authors.lastname: Cayre
authors.forename: Arndt
authors.initials: A
authors.lastname: Benecke
authors.forename: Pierre G
authors.initials: PG
authors.lastname: Lutz
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D044842:Cullin Proteins / Q000378:metabolism*; D000075065:Elongin; D006801:Humans; D007938:Leukemia / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D046912:Multiprotein Complexes / Q000737:chemistry / Q000378:metabolism; D009154:Mutation; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D044842:Cullin Proteins; C000616395:ELOC protein, human; D000075065:Elongin; D046912:Multiprotein Complexes; D014157:Transcription Factors; D044767:Ubiquitin-Protein Ligases; D046988:Proteasome Endopeptidase Complex