B-cell lymphoma 6 protein - P41182 (BCL6_HUMAN)

 

Protein Feature View of PDB entries mapped to a UniProtKB sequence  

  • Number of PDB entries for P41182: 34
 
Function
Transcriptional repressor mainly required for germinal center (GC) formation and antibody affinity maturation which has different mechanisms of action specific to the lineage and biological functions. Forms complexes with different corepressors and histone deacetylases to repress the transcriptional expression of different subsets of target genes. Represses its target genes by binding directly to the DNA sequence 5'-TTCCTAGAA-3' (BCL6-binding site) or indirectly by repressing the transcriptional activity of transcription factors. In GC B-cells, represses genes that function in differentiation, inflammation, apoptosis and cell cycle control, also autoregulates its transcriptional expression and up-regulates, indirectly, the expression of some genes important for GC reactions, such as AICDA, through the repression of microRNAs expression, like miR155. An important function is to allow GC B-cells to proliferate very rapidly in response to T-cell dependent antigens and tolerate the physiological DNA breaks required for immunglobulin class switch recombination and somatic hypermutation without inducing a p53/TP53-dependent apoptotic response. In follicular helper CD4(+) T-cells (T(FH) cells), promotes the expression of T(FH)-related genes but inhibits the differentiation of T(H)1, T(H)2 and T(H)17 cells. Also required for the establishment and maintenance of immunological memory for both T- and B-cells. Suppresses macrophage proliferation through competition with STAT5 for STAT-binding motifs binding on certain target genes, such as CCL2 and CCND2. In response to genotoxic stress, controls cell cycle arrest in GC B-cells in both p53/TP53-dependedent and -independent manners. Besides, also controls neurogenesis through the alteration of the composition of NOTCH-dependent transcriptional complexes at selective NOTCH targets, such as HES5, including the recruitment of the deacetylase SIRT1 and resulting in an epigenetic silencing leading to neuronal differentiation. UniProt
Pathway Maps
Maps:       
Reactions:
      ESCHER  BiGG
Subunit Structure
Homodimer. Interacts (via BTB domain) with the corepressors BCOR, NCOR1 and SMRT/NCOR2; the interactions are direct. Forms preferably ternary complexes with BCOR and SMRT/NCOR2 on target gene promoters but, on enhancer elements, interacts with SMRT/NCOR2 and HDAC3 to repress proximal gene expression. Interacts with histone deacetylases HDAC2, HDAC5 and HDAC9 (via the catalytic domain). Interacts with ZBTB7 and BCL6B. Interacts with SCF(FBXO11) complex; the interaction is independent of phosphorylation and promotes ubiquitination. Interacts (when phosphorylated) with PIN1; the interaction is required for BCL6 degradation upon genotoxic stress. Interacts with ZBTB17; inhibits ZBTB17 transcriptional activity. Interacts with CTBP1, autoinhibits its transcriptional expression. Interacts with NOTCH1 NCID and SIRT1; leads to a epigenetic repression of selective NOTCH1-target genes. Interacts (nor via BTB domain neither acetylated) with the NuRD complex components CHD4, HDAC1, MBD3 and MTA3; the interaction with MTA3 inhibits BCL6 acetylation and is required for BCL6 transpriptional repression. UniProt
Domain
The BTB domain mediates homodimerization. Its dimer interface mediates peptide binding such as to corepressors BCOR and NCOR2 (PubMed:18212045). Interaction with corepressors through the BTB domain is needed to facilitate the rapid proliferation and survival of GC B-cells but is not involved in the T(FH) formation and BCL6-mediated suppression of T(H)2 and T(H)17 differentiationrequired for GC formation (By similarity). UniProt
Legend
The Protein Feature View requires a browser that supports SVG (Scalable Vector Graphics). Mouse over tracks and labels for more information.
Data origin/color codes
The vertical color bar on the left side indicates data provenance.
Data in green originates from UniProtKB  
Variation data (sourced from UniProt) shows non-genetic variation from the ExPASy   and dbSNP   websites.
Data in yellow originates from Pfam  , by interacting with the HMMER3 web site  
Data in purple originates from Phosphosite  .
Data in orange originates from the SCOP   (version 1.75) and SCOPe   (version 2.04) classifications.
Data in grey has been calculated using BioJava  . Protein disorder predictions are based on JRONN (Troshin, P. and Barton, G. J. unpublished), a Java implementation of RONN  
  • Red: potentially disorderd region
  • Blue: probably ordered region.
Hydropathy has been calculated using a sliding window of 15 residues and summing up scores from standard hydrophobicity tables.
  • Red: hydrophobic
  • Blue: hydrophilic.
Data in lilac represent the genomic exon structure projected onto the UniProt sequence.
Data in blue originates from PDB
  • Secstruc: Secondary structure projected from representative PDB entries onto the UniProt sequence.
Sequence Mismatches It is now possible to see information about expression tags, cloning artifacts, and many other details related to sequence mismatches.
Icons represent a number of different sequence modifications that can be observed in PDB files. For example the 'T' icon T represents expression tags that have been added to the sequence. The 'E' icon E represents an engineered mutation. However, besides these two, there are many other icons. For more information about the meaning and exact position of a sequence modification, move the cursor over the icon.
Validation Track

For more details on the Validation Track (Structure Summary Page only) see the dedicated help page.

Data in red indicates combined ranges of Homology Models from the SWISS-MODEL Repository  
The PDB to UniProt mapping is based on the data provided by the EBI SIFTS project. See also Velankar et al., Nucleic Acids Research 33, D262-265 (2005).
Organism icons generated by flaticon.com under CC BY. The authors are: Freepik, Icons8, OCHA, Scott de Jonge.

For more details on the Protein Feature view see the dedicated help page.