| Autor: |
Kim, Jinyong, Cantwell, Carrie A., Johnson, Peter F., Pfarr, Curt M., Williams, Simon C. |
| Zdroj: |
Journal of Biological Chemistry; October 2002, Vol. 277 Issue: 41 p38037-38044, 8p |
| Abstrakt: |
CCAAT/enhancer-binding proteins (C/EBPs) are basic region/leucine zipper transcription factors that function as regulators of cell growth and differentiation in numerous cell types. We previously localized transcriptional activation and inhibitory regions in one family member, C/EBPε. Here we describe the further characterization of a C/EBPε inhibitory domain termed regulatory domain I. We show that functionally related domains are present in C/EBPα, C/EBPβ, and C/EBPδ. These domains contain an evolutionarily conserved five-amino acid motif (the regulatory domain motif (RDM)) that conforms to the consensus sequence (I/V/L)KXEP. Mutagenesis studies revealed that the residues at positions 1, 2, and 4 of the RDM are critical for inhibitory domain function. Data base searches identified RDM-like sequences in a number of nuclear proteins. We found that small regions from c-Jun, JunB, and JunD containing this sequence also function as transcriptional inhibitory domains. Importantly, the RDM is similar to the recognition sequence for attachment of the ubiquitin-like protein, small ubiquitin-like modifier-1 (SUMO-1), and the conserved lysine residue of each C/EBP RDM served as an attachment site for SUMO-1. SUMO-1 attachment decreased the inhibitory effect of the C/EBPε regulatory domain, suggesting that sumoylation may play an important role in modulating C/EBPε activity as well as that of the other C/EBP family members. |
| Databáze: |
Supplemental Index |
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