| Structural highlights
Function
FBX44_HUMAN Substrate-recognition component of the SCF (SKP1-CUL1-F-box protein)-type E3 ubiquitin ligase complex.FBX2_MOUSE Substrate recognition component of a SCF (SKP1-CUL1-F-box protein) E3 ubiquitin-protein ligase complex that mediates the ubiquitination and subsequent proteasomal degradation of target proteins. Involved in the endoplasmic reticulum-associated degradation pathway (ERAD) for misfolded lumenal proteins by recognizing and binding sugar chains on unfolded glycoproteins that are retrotranslocated into the cytosol and promoting their ubiquitination and subsequent degradation. Prevents formation of cytosolic aggregates of unfolded glycoproteins that have been retrotranslocated into the cytosol. Able to recognize and bind denatured glycoproteins, preferentially those of the high-mannose type.[1] [2] [3] [4] [5]
Publication Abstract from PubMed
The SCF ubiquitin ligase comprises four components: Skp1, Cul1, Rbx1 and a variable-subunit F-box protein. The F-box protein Fbs1, which recognizes the N-linked glycoproteins, is involved in the endoplasmic reticulum-associated degradation pathway. Although FBG3, another F-box protein, shares 51% sequence identity with Fbs1, FBG3 does not bind glycoproteins. To investigate the sequence-structure relationship of the substrate-binding pocket, the crystal structure of a mutant substrate-binding domain of Fbs1 in which the six nonconserved regions (beta1, beta2-beta3, beta3-beta4, beta5-beta6, beta7-beta8 and beta9-beta10) of Fbs1 were substituted with those of FBG3 was determined. The substrate-binding pocket of this model exhibits structural features that differ from those of Fsb1.
Structural analysis of a function-associated loop mutant of the substrate-recognition domain of Fbs1 ubiquitin ligase.,Nishio K, Yoshida Y, Tanaka K, Mizushima T Acta Crystallogr F Struct Biol Commun. 2016 Aug;72(Pt 8):619-26. doi:, 10.1107/S2053230X16011018. Epub 2016 Jul 27. PMID:27487926[6]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Yoshida Y, Chiba T, Tokunaga F, Kawasaki H, Iwai K, Suzuki T, Ito Y, Matsuoka K, Yoshida M, Tanaka K, Tai T. E3 ubiquitin ligase that recognizes sugar chains. Nature. 2002 Jul 25;418(6896):438-42. PMID:12140560 doi:10.1038/nature00890
- ↑ Yoshida Y, Adachi E, Fukiya K, Iwai K, Tanaka K. Glycoprotein-specific ubiquitin ligases recognize N-glycans in unfolded substrates. EMBO Rep. 2005 Mar;6(3):239-44. PMID:15723043 doi:http://dx.doi.org/10.1038/sj.embor.7400351
- ↑ Yamaguchi Y, Hirao T, Sakata E, Kamiya Y, Kurimoto E, Yoshida Y, Suzuki T, Tanaka K, Kato K. Fbs1 protects the malfolded glycoproteins from the attack of peptide:N-glycanase. Biochem Biophys Res Commun. 2007 Oct 26;362(3):712-6. Epub 2007 Aug 20. PMID:17720138 doi:http://dx.doi.org/10.1016/j.bbrc.2007.08.056
- ↑ Yoshida Y, Murakami A, Iwai K, Tanaka K. A neural-specific F-box protein Fbs1 functions as a chaperone suppressing glycoprotein aggregation. J Biol Chem. 2007 Mar 9;282(10):7137-44. Epub 2007 Jan 10. PMID:17215248 doi:http://dx.doi.org/10.1074/jbc.M611168200
- ↑ Mizushima T, Hirao T, Yoshida Y, Lee SJ, Chiba T, Iwai K, Yamaguchi Y, Kato K, Tsukihara T, Tanaka K. Structural basis of sugar-recognizing ubiquitin ligase. Nat Struct Mol Biol. 2004 Apr;11(4):365-70. Epub 2004 Feb 29. PMID:14990996 doi:http://dx.doi.org/10.1038/nsmb732
- ↑ Nishio K, Yoshida Y, Tanaka K, Mizushima T. Structural analysis of a function-associated loop mutant of the substrate-recognition domain of Fbs1 ubiquitin ligase. Acta Crystallogr F Struct Biol Commun. 2016 Aug;72(Pt 8):619-26. doi:, 10.1107/S2053230X16011018. Epub 2016 Jul 27. PMID:27487926 doi:http://dx.doi.org/10.1107/S2053230X16011018
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