Engineered leucine zippers show that hemiphosphorylated CREB complexes are transcriptionally active.
AUTOR(ES)
Loriaux, M M
RESUMO
The ability of basic/leucine zipper transcription factors to form homo- and heterodimers potentially increases the diversity of signaling pathways that can impinge upon a single genetic element. The capacity of these proteins to dimerize in various combinations complicates the analysis of their functional properties, however. To simplify the functional analysis of CREB dimers, we mutated selected residues within the leucine zipper region to generate proteins that could only heterodimerize. These mutants allowed us to determine whether phosphorylation of both CREB subunits was necessary for transcriptional activation. Our results reveal that hemiphosphorylated CREB dimers are half as active as fully phosphorylated dimers. It is possible, therefore, that the degree of phosphorylation of CREB complexes could modulate the transcriptional responses of specific genes to cAMP.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=47498Documentos Relacionados
- Computational approaches to identify leucine zippers.
- Miniribozymes, small derivatives of the sunY intron, are catalytically active.
- Beta subunits of human choriogonadotropin and ovine lutropin are biologically active.
- Human immunodeficiency virus type 1 gag-protease fusion proteins are enzymatically active.
- The ets sequence from the transforming gene of avian erythroblastosis virus, E26, has unique domains on human chromosomes 11 and 21: both loci are transcriptionally active.