title: Phosphorylation of serine 323 of ASB2α is pivotal for the targeting of filamin A to degradation.
abstract: ASB proteins are the specificity subunits of cullin5-RING E3 ubiquitin ligases (CRL5) that play roles in ubiquitin-mediated protein degradation. However, how their activity is regulated remains poorly understood. Here, we unravel a novel mechanism of regulation of a CRL5 through phosphorylation of its specificity subunit ASB2α. Indeed, using mass spectrometry, we showed for the first time that ASB2α is phosphorylated and that phosphorylation of serine-323 (Ser-323) of ASB2α is crucial for the targeting of the actin-binding protein filamin A (FLNa) to degradation. Mutation of ASB2α Ser-323 to Ala had no effect on intrinsic E3 ubiquitin ligase activity of ASB2α but abolished the ability of ASB2α to induce degradation of FLNa. In contrast, the ASB2α Ser-323 to Asp phosphomimetic mutant induced acute degradation of FLNa. Moreover, inhibition of the extracellular signal-regulated kinases 1 and 2 (Erk1/2) activity reduced ASB2α-mediated FLNa degradation. We further showed that the subcellular localization of ASB2α to actin-rich structures is dependent on ASB2α Ser-323 phosphorylation and propose that the interaction with FLNa depends on the electrostatic potential redistribution induced by the Ser-323 phosphate group. Taken together, these data unravel an important mechanism by which ASB2α-mediated FLNa degradation can be regulated.
authors.affiliation: CNRS; IPBS (Institut de Pharmacologie et de Biologie Structurale), 205 route de Narbonne BP 64182, F-31077 Toulouse, France; Université de Toulouse, UPS, IPBS, F-31077 Toulouse, France.
authors.forename: Rim
authors.initials: R
authors.lastname: Zakaria
authors.forename: Isabelle
authors.initials: I
authors.lastname: Lamsoul
authors.forename: Sandrine
authors.initials: S
authors.lastname: Uttenweiler-Joseph
authors.forename: Monique
authors.initials: M
authors.lastname: Erard
authors.forename: Bernard
authors.initials: B
authors.lastname: Monsarrat
authors.forename: Odile
authors.initials: O
authors.lastname: Burlet-Schiltz
authors.forename: Christel
authors.initials: C
authors.lastname: Moog-Lutz
authors.forename: Pierre G
authors.initials: PG
authors.lastname: Lutz
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D064448:Filamins / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010766:Phosphorylation; D059748:Proteolysis; D012694:Serine / Q000032:analysis / Q000378:metabolism*; D050826:Suppressor of Cytokine Signaling Proteins / Q000737:chemistry / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism
chemical_list: C437987:ASB2 protein, human; D064448:Filamins; D050826:Suppressor of Cytokine Signaling Proteins; D012694:Serine; D044767:Ubiquitin-Protein Ligases; D048049:Extracellular Signal-Regulated MAP Kinases
keywords: AML; APL; AR; ASB; CID; CRL5; Cullin-RING E3 ubiquitin ligase; E3; E3 ubiquitin ligase; ETD; Erk; FLN; Filamin; Mass spectrometry; Post-translational modifications; acute myeloid leukemia; acute promyelocytic leukemia; ankyrin repeat; collision-induced dissociation; cullin5-RING E3 ubiquitin ligases; electron transfer dissociation; extracellular signal-regulated kinase; filamin