title: 3BP2 adapter protein is required for receptor activator of NFκB ligand (RANKL)-induced osteoclast differentiation of RAW264.7 cells.
abstract: The adapter protein 3BP2 (also known as SH3BP2 and Abl SH3-binding protein 2) has been involved in leukocyte signaling and activation downstream immunoreceptors. Genetic studies have further associated 3BP2 mutations to the human disease cherubism and to inflammation and bone dysfunction in mouse. However, how wild type 3BP2 functions in macrophage differentiation remains poorly understood. In this study, using small interfering RNA-mediated silencing of 3BP2 in the RAW264.7 monocytic cell line, we show that 3BP2 was required for receptor activator of NFkappaB ligand (RANKL)-induced differentiation of RAW264.7 cells into multinucleated mature osteoclasts but not for granulocyte macrophage-colony stimulating factor/interleukin-4-induced differentiation into dendritic cells. 3BP2 silencing was associated with impaired activation of multiple signaling events downstream of RANK, including actin reorganization; Src, ERK, and JNK phosphorylation; and up-regulation of osteoclastogenic factors. In addition, 3BP2 knockdown cells induced to osteoclast by RANKL displayed a reduced increase of Src and nuclear factor of activated T cells (NFATc1) mRNA and protein expression. Importantly, 3BP2 interacted with Src, Syk, Vav, and Cbl in monocytic cells, and the introduction of constitutively active mutants of Src and NFATc1 in 3BP2-deficient cells restored osteoclast differentiation. Finally, the expression of a 3BP2 cherubism mutant was found to promote increased Src activity and NFAT-dependent osteoclast formation. Together, this study demonstrates that wild type 3BP2 is a key regulator of RANK-mediated macrophage differentiation into osteoclast through Src and NFATc1 activation.
authors.affiliation: INSERM, UMR576, Hôpital de l'Archet, Nice F-06202, France.
authors.forename: Amel
authors.initials: A
authors.lastname: GuezGuez
authors.forename: Virginie
authors.initials: V
authors.lastname: Prod'homme
authors.forename: Xavier
authors.initials: X
authors.lastname: Mouska
authors.forename: Alice
authors.initials: A
authors.lastname: Baudot
authors.forename: Claudine
authors.initials: C
authors.lastname: Blin-Wakkach
authors.forename: Robert
authors.initials: R
authors.lastname: Rottapel
authors.forename: Marcel
authors.initials: M
authors.lastname: Deckert
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation / Q000502:physiology*; D002460:Cell Line; D017931:DNA Primers; D005816:Genetic Complementation Test; D006801:Humans; D008264:Macrophages / Q000166:cytology / Q000502:physiology; D051379:Mice; D009000:Monocytes / Q000166:cytology / Q000502:physiology; D010010:Osteoclasts / Q000166:cytology* / Q000502:physiology; D016133:Polymerase Chain Reaction; D053245:RANK Ligand / Q000502:physiology*; D016372:RNA, Antisense / Q000235:genetics; D014162:Transfection
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D017931:DNA Primers; D053245:RANK Ligand; D016372:RNA, Antisense; C109073:SH3BP2 protein, human; C484644:Sh3bp2 protein, mouse; C505689:Tnfsf11 protein, mouse