1r8u
From Proteopedia
NMR structure of CBP TAZ1/CITED2 complex
Structural highlights
Disease[CITE2_HUMAN] Defects in CITED2 are a cause of ventricular septal defect type 2 (VSD2) [MIM:614431]. VSD2 is a common form of congenital cardiovascular anomaly that may occur alone or in combination with other cardiac malformations. It can affect any portion of the ventricular septum, resulting in abnormal communications between the two lower chambers of the heart. Classification is based on location of the communication, such as perimembranous, inlet, outlet (infundibular), central muscular, marginal muscular, or apical muscular defect. Large defects that go unrepaired may give rise to cardiac enlargement, congestive heart failure, pulmonary hypertension, Eisenmenger's syndrome, delayed fetal brain development, arrhythmias, and even sudden cardiac death.[1] Defects in CITED2 are a cause of atrial septal defect type 8 (ASD8) [MIM:614433]. ASD8 is a congenital heart malformation characterized by incomplete closure of the wall between the atria resulting in blood flow from the left to the right atria.[2] Function[CITE2_HUMAN] Transcriptional coactivator of the p300/CBP-mediated trancription complex. Acts as a bridge, linking TFAP2 transcription factors and the p300/CBP transcriptional coactivator complex in order to stimulate TFAP2-mediated transcriptional activation. Positively regulates TGF-beta signaling through its association with the SMAD/p300/CBP-mediated transcriptional coactivator complex. Stimulates the peroxisome proliferator-activated receptors PPARA transcriptional activity. Enhances estrogen-dependent transactivation mediated by estrogen receptors. Acts also as a transcriptional corepressor; interferes with the binding of the transcription factors HIF1A or STAT2 and the p300/CBP transcriptional coactivator complex. Participates in sex determination and early gonad development by stimulating transcription activation of SRY. Plays a role in controlling left-right patterning during embryogenesis; potentiates transcriptional activation of NODAL-mediated gene transcription in the left lateral plate mesoderm (LPM). Plays an essential role in differentiation of the adrenal cortex from the adrenogonadal primordium (AGP); stimulates WT1-mediated transcription activation thereby up-regulating the nuclear hormone receptor NR5A1 promoter activity. Associates with chromatin to the PITX2 P1 promoter region.[3] [4] [5] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe TAZ1 domain of the homologous transcriptional coactivators CREB-binding protein (CBP) and p300 forms a complex with CITED2 (CBP/p300-interacting transactivator with ED-rich tail), inhibiting the activity of the hypoxia inducible factor (HIF-1alpha) and thereby attenuating the cellular response to low tissue oxygen concentration. We report the NMR structure of the CBP TAZ1 domain bound to the activation domain of CIT-ED2. The structure of TAZ1, consisting of four alpha-helices (alpha(1)-alpha(4)) stabilized by three zinc atoms, is very similar in the CITED2 and HIF-1alpha complexes. The activation domain of CITED2 is unstructured when free and folds upon binding, forming a helix (termed alpha(A)) and an extended structure that wraps around TAZ1. The CITED2 alpha(A) helix packs in the TAZ1 alpha(1)/alpha(4) interface, a site that forms weak interactions with the poorly defined aminoterminal alpha-helix of HIF-1alpha. CITED2 and HIF-1alpha both contain a four residue motif, LP(E/Q)L, which binds in the TAZ1 alpha(1)/alpha(2)/alpha(3) junction in each complex. The carboxyl-terminal region of CITED2 forms an extended structure with hydrophobic contacts in the TAZ1 alpha(1)/alpha(3) interface in the site occupied by the HIF-1alpha alpha(B) helix. CITED2 does not bind at all to the TAZ1 site occupied by the HIF-1alpha carboxyl-terminal helix. The HIF-1alpha and CITED2 domains utilize partly overlapping surfaces of TAZ1 to achieve high affinity binding and to compete effectively with each other for interaction with CBP/p300; CITED2 and HIF-1alpha use these binding sites differently to maintain similar binding affinities in order to displace each other in a feedback loop during the hypoxic response. Interaction of the TAZ1 domain of the CREB-binding protein with the activation domain of CITED2: regulation by competition between intrinsically unstructured ligands for non-identical binding sites.,De Guzman RN, Martinez-Yamout MA, Dyson HJ, Wright PE J Biol Chem. 2004 Jan 23;279(4):3042-9. Epub 2003 Oct 31. PMID:14594809[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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