| Structural highlights
Function
[1433Z_HUMAN] Adapter protein implicated in the regulation of a large spectrum of both general and specialized signaling pathways. Binds to a large number of partners, usually by recognition of a phosphoserine or phosphothreonine motif. Binding generally results in the modulation of the activity of the binding partner.[1] [2] [3] [4] [5]
Publication Abstract from PubMed
The partially disordered Chibby (Cby) is a conserved nuclear protein that antagonizes the Wnt/beta-catenin signaling pathway. By competing with the Tcf/Lef family proteins for binding to beta-catenin, Cby abrogates the beta-catenin-mediated transcription of Wnt signaling genes. Additionally, upon phosphorylation on S20 by the kinase Akt, Cby forms a complex with 14-3-3 to facilitate the nuclear export of beta-catenin, which represents another crucial mechanism for the regulation of Wnt signaling. To obtain a mechanistic understanding of the 14-3-3/Cby interaction, we have extensively characterized the complex using X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, and isothermal titration calorimetry (ITC). The crystal structure of the human 14-3-3zeta/Cby protein-peptide complex reveals a canonical binding mode; however the residue at the +2 position from the phosphorylated serine is shown to be uniquely oriented relative to other solved structures of 14-3-3 complexes. Our ITC results illustrate that although the phosphorylation of S20 is essential for Cby to recognize 14-3-3, residues flanking the phosphorylation site also contribute to the binding affinity. However, as is commonly observed in other 14-3-3/phosphopeptide crystal structures, residues of Cby flanking the 14-3-3 binding motif lack observable electron density. To obtain a more detailed binding interface, we have completed the backbone NMR resonance assignment of 14-3-3zeta. NMR titration experiments reveal that residues outside of the 14-3-3 conserved binding cleft, namely a flexible loop consisting of residues 203-210, are also involved in binding Cby. By using a combined X-ray and NMR approach, we have dissected the molecular basis of the 14-3-3/Cby interaction.
Structural Analysis of the 14-3-3zeta/Chibby Interaction Involved in Wnt/beta-Catenin Signaling.,Killoran RC, Fan J, Yang D, Shilton BH, Choy WY PLoS One. 2015 Apr 24;10(4):e0123934. doi: 10.1371/journal.pone.0123934., eCollection 2015. PMID:25909186[6]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Dubois T, Rommel C, Howell S, Steinhussen U, Soneji Y, Morrice N, Moelling K, Aitken A. 14-3-3 is phosphorylated by casein kinase I on residue 233. Phosphorylation at this site in vivo regulates Raf/14-3-3 interaction. J Biol Chem. 1997 Nov 14;272(46):28882-8. PMID:9360956
- ↑ Zheng W, Zhang Z, Ganguly S, Weller JL, Klein DC, Cole PA. Cellular stabilization of the melatonin rhythm enzyme induced by nonhydrolyzable phosphonate incorporation. Nat Struct Biol. 2003 Dec;10(12):1054-7. Epub 2003 Oct 26. PMID:14578935 doi:10.1038/nsb1005
- ↑ Tsuruta F, Sunayama J, Mori Y, Hattori S, Shimizu S, Tsujimoto Y, Yoshioka K, Masuyama N, Gotoh Y. JNK promotes Bax translocation to mitochondria through phosphorylation of 14-3-3 proteins. EMBO J. 2004 Apr 21;23(8):1889-99. Epub 2004 Apr 8. PMID:15071501 doi:10.1038/sj.emboj.7600194
- ↑ Ganguly S, Weller JL, Ho A, Chemineau P, Malpaux B, Klein DC. Melatonin synthesis: 14-3-3-dependent activation and inhibition of arylalkylamine N-acetyltransferase mediated by phosphoserine-205. Proc Natl Acad Sci U S A. 2005 Jan 25;102(4):1222-7. Epub 2005 Jan 11. PMID:15644438 doi:0406871102
- ↑ Gu YM, Jin YH, Choi JK, Baek KH, Yeo CY, Lee KY. Protein kinase A phosphorylates and regulates dimerization of 14-3-3 epsilon. FEBS Lett. 2006 Jan 9;580(1):305-10. Epub 2005 Dec 19. PMID:16376338 doi:S0014-5793(05)01485-7
- ↑ Killoran RC, Fan J, Yang D, Shilton BH, Choy WY. Structural Analysis of the 14-3-3zeta/Chibby Interaction Involved in Wnt/beta-Catenin Signaling. PLoS One. 2015 Apr 24;10(4):e0123934. doi: 10.1371/journal.pone.0123934., eCollection 2015. PMID:25909186 doi:http://dx.doi.org/10.1371/journal.pone.0123934
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