DDB1-CUL4-X-box complex
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Function
- E3 ubiquitin-protein ligase complex
- DDB1 may recruit specific substrate targeting subunits to the DCX complex
- these substrate targeting subunits are generally known as DCAF (DDB1- & CUL4-associated factor) or CDW (CUL4-DDB1-associated WD40-repeat) proteins
- DCX complexes may associate with the COP9 signalosome, & this inhibits the E3 ubiquitin-protein ligase activity of the complex
Structure
- subunits seem to include DDB1, CUL4A or CUL4B, RBX1 & a variable substrate recognition components DCAF or CDW (see above)
Notes
- DDCX complexes include
- DCX(DET1-COP1) complex with the substrate recognition component DET1 & COP1
- DCX(DDB2) complex
- also known as
- substrate recognition component DDB2
- may ubiquitinate histone H2A, histone H3 & histone H4 at sites of UV-induced DNA damage
- ubiquitination of histones may facilitate their removal from the nucleosome & promote subsequent DNA repair
- also ubiquitinates XPC, which may enhance DNA-binding by XPC & promote nucleotide excision repair
- DCX(ERCC8) complex
- putative substrate recognition component ERCC8
- role in transcription-coupled repair (TCR)
- role in ubiquitination of CDKN1B/p27kip when associated with CUL4 & SKP2
- DCX(DTL) complex
- putative substrate recognition component DTL
- role in PCNA-dependent polyubiquitination of CDT1
- MDM2-dependent ubiquitination of TP53 in response to radiation-induced DNA damage & during DNA replication