| Structural highlights
Function
[CBP_MOUSE] Acetylates histones, giving a specific tag for transcriptional activation. Also acetylates non-histone proteins, like NCOA3 and FOXO1. Binds specifically to phosphorylated CREB and enhances its transcriptional activity toward cAMP-responsive genes. Acts as a coactivator of ALX1 in the presence of EP300 (By similarity).[1] [2] [3] [4] [MYB_MOUSE] Transcriptional activator; DNA-binding protein that specifically recognize the sequence 5'-YAAC[GT]G-3'. Plays an important role in the control of proliferation and differentiation of hematopoietic progenitor cells.
Publication Abstract from PubMed
The human T cell leukemia virus I basic leucine zipper protein (HTLV-1 HBZ) maintains chronic viral infection and promotes leukemogenesis through poorly understood mechanisms involving interactions with the KIX domain of the transcriptional coactivator CBP and its paralog p300. The KIX domain binds regulatory proteins at the distinct MLL and c-Myb/pKID sites to form binary or ternary complexes. The intrinsically disordered N-terminal activation domain of HBZ (HBZ AD) deregulates cellular signaling pathways by competing directly with cellular and viral transcription factors for binding to the MLL site and by allosterically perturbing binding of the transactivation domain of the hematopoietic transcription factor c-Myb. Crystal structures of the ternary KIX:c-Myb:HBZ complex show that the HBZ AD recruits two KIX:c-Myb entities through tandem amphipathic motifs (L/V)(V/L)DGLL and folds into a long alpha-helix upon binding. Isothermal titration calorimetry reveals strong cooperativity in binding of the c-Myb activation domain to the KIX:HBZ complex and in binding of HBZ to the KIX:c-Myb complex. In addition, binding of KIX to the two HBZ (V/L)DGLL motifs is cooperative; the structures suggest that this cooperativity is achieved through propagation of the HBZ alpha-helix beyond the first binding motif. Our study suggests that the unique structural flexibility and the multiple interaction motifs of the intrinsically disordered HBZ AD are responsible for its potency in hijacking KIX-mediated transcription pathways. The KIX:c-Myb:HBZ complex provides an example of cooperative stabilization in a transcription factor:coactivator network and gives insights into potential mechanisms through which HBZ dysregulates hematopoietic transcriptional programs and promotes T cell proliferation.
Structural basis for cooperative regulation of KIX-mediated transcription pathways by the HTLV-1 HBZ activation domain.,Yang K, Stanfield RL, Martinez-Yamout MA, Dyson HJ, Wilson IA, Wright PE Proc Natl Acad Sci U S A. 2018 Sep 19. pii: 1810397115. doi:, 10.1073/pnas.1810397115. PMID:30232260[5]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Hung HL, Lau J, Kim AY, Weiss MJ, Blobel GA. CREB-Binding protein acetylates hematopoietic transcription factor GATA-1 at functionally important sites. Mol Cell Biol. 1999 May;19(5):3496-505. PMID:10207073
- ↑ Xu W, Chen H, Du K, Asahara H, Tini M, Emerson BM, Montminy M, Evans RM. A transcriptional switch mediated by cofactor methylation. Science. 2001 Dec 21;294(5551):2507-11. Epub 2001 Nov 8. PMID:11701890 doi:10.1126/science.1065961
- ↑ Daitoku H, Hatta M, Matsuzaki H, Aratani S, Ohshima T, Miyagishi M, Nakajima T, Fukamizu A. Silent information regulator 2 potentiates Foxo1-mediated transcription through its deacetylase activity. Proc Natl Acad Sci U S A. 2004 Jul 6;101(27):10042-7. Epub 2004 Jun 25. PMID:15220471 doi:10.1073/pnas.0400593101
- ↑ Kuo HY, Chang CC, Jeng JC, Hu HM, Lin DY, Maul GG, Kwok RP, Shih HM. SUMO modification negatively modulates the transcriptional activity of CREB-binding protein via the recruitment of Daxx. Proc Natl Acad Sci U S A. 2005 Nov 22;102(47):16973-8. Epub 2005 Nov 15. PMID:16287980 doi:10.1073/pnas.0504460102
- ↑ Yang K, Stanfield RL, Martinez-Yamout MA, Dyson HJ, Wilson IA, Wright PE. Structural basis for cooperative regulation of KIX-mediated transcription pathways by the HTLV-1 HBZ activation domain. Proc Natl Acad Sci U S A. 2018 Sep 19. pii: 1810397115. doi:, 10.1073/pnas.1810397115. PMID:30232260 doi:http://dx.doi.org/10.1073/pnas.1810397115
|
