4f7r
From Proteopedia
Crystal structure of 14-3-3 protein from Giardia intestinalis
Structural highlights
Function1433_GIAIC 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 (By similarity). Binds with varying affinity to various synthetic phosphopeptides having a consensus binding motif RSX(pS/pT)XP, called mode-1, where X is any residue and pS/pT is a phosphorylated serine/threonine, and to synthetic phosphopeptides having a consensus binding motif Xp(S/T)X1-2-COOH, called mode-3, in which the phosphorylated residue occupies the penultimate C-terminal position in the target protein, but does not bind to their unphosphorylated counterparts (PubMed:19733174). Binds to synthetic human RAF1 phosphopeptides, but not to their unphosphorylated forms. Binds to difopein, a polypeptide containing a phosphorylation-independent binding motif (PubMed:16368691, PubMed:19733174). Involved in encystation (PubMed:19733174). Involved in cell proliferation. Required for actin and tubulin cytoskeletal organization. Regulates actin filament formation and nuclear size (PubMed:28932813).[UniProtKB:P62261][1] [2] [3] Publication Abstract from PubMedThe 14-3-3s are a family of dimeric evolutionary conserved pSer/pThr binding proteins that play a key role in multiple biological processes by interacting with a plethora of client proteins. Giardia duodenalis is a flagellated protozoan that affects millions of people worldwide causing an acute and chronic diarrheal disease. The single giardial 14-3-3 isoform (g14-3-3), unique in the 14-3-3 family, needs the constitutive phosphorylation of Thr214 and the polyglycylation of its C-terminus to be fully functional in vivo. Alteration of the phosphorylation and polyglycylation status affects the parasite differentiation into the cyst stage. To further investigate the role of these post-translational modifications, the crystal structure of the g14-3-3 was solved in the unmodified apo form. Oligomers of g14-3-3 were observed due to domain swapping events at the protein C-terminus. The formation of filaments was supported by TEM. Mutational analysis, in combination with native PAGE and chemical cross-linking, proved that polyglycylation prevents oligomerization. In silico phosphorylation and molecular dynamics simulations supported a structural role for the phosphorylation of Thr214 in promoting target binding. Our findings highlight unique structural features of g14-3-3 opening novel perspectives on the evolutionary history of this protein family and envisaging the possibility to develop anti-giardial drugs targeting g14-3-3. The Crystal Structure of Giardia duodenalis 14-3-3 in the Apo Form: When Protein Post-Translational Modifications Make the Difference.,Fiorillo A, di Marino D, Bertuccini L, Via A, Pozio E, Camerini S, Ilari A, Lalle M PLoS One. 2014 Mar 21;9(3):e92902. doi: 10.1371/journal.pone.0092902. eCollection, 2014. PMID:24658679[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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