The tight regulation of gene transcription is crucial to many biological processes. Up- or down-regulating the transcription of a single gene can involve several different proteins, and oftentimes requires chemical modifications such as the phosphorylation or acetylation of these proteins. A paper in the March issue of Nature Structural Biology reports the direct association of a protein phosphatase with a histone deacetylase. The results show how the combined function of these two enzymes represses the activity of an important transcription factor, CREB.
Phosphorylation of CREB leads to the acetylation of histone proteins at the target gene and activates gene transcription. Conversely, dephosphorylation of CREB turns off transcriptional activation, but how that links to histone deacetylation was not clear. Marc Montminy and collaborators at the Salk Institute for Biological Studies provide evidence that PP1, an enzyme that dephosphorylates CREB, exists in a complex with an enzyme called HDAC1, a histone deacetylase. While CREB binds HDAC1 directly, the complex of PP1 and HDAC1 can block phosphorylation of CREB (or stimulate its dephosphorylation), as well as deacetylate CREB-bound promoters. The paper offers an example of how distinct protein modifications are coordinated to achieve strict control over cellular gene expression.
Marc R. Montminy
The Salk Institute for Biological Studies
La Jolla, CA, USA
Tel: +1 858 259 1829
Also available online.
(C) Nature Structural Biology press release.
Message posted by: Trevor M. D'Souza