View source for GCN5

== Overview ==

[[GCN5]] (General Control Non-derepressible 5) is a [[histone acetyltransferase]] (HAT) enzyme that plays a pivotal role in [[transcriptional regulation]]. This enzyme is part of the larger [[GCN5-related N-acetyltransferase]] (GNAT) superfamily, which is known for its involvement in a wide range of cellular processes, including [[cell cycle]] regulation, [[DNA repair]], and [[apoptosis]]. 

[[Image:Detail-58654.jpg|thumb|center|A close-up view of the GCN5 enzyme.|class=only_on_mobile]]
[[Image:Detail-58655.jpg|thumb|center|A close-up view of the GCN5 enzyme.|class=only_on_desktop]]

== Structure and Function ==

GCN5 is a multifunctional enzyme that possesses both acetyltransferase and [[protein kinase]] activities. The acetyltransferase activity of GCN5 is responsible for the acetylation of [[histone]] proteins, a process that is crucial for the regulation of gene expression. The protein kinase activity, on the other hand, allows GCN5 to phosphorylate target proteins, thereby modulating their activity and function.

The structure of GCN5 is characterized by a conserved [[acetyl-CoA]] binding site and a unique [[bromodomain]], which recognizes and binds to acetylated histones. The presence of these domains enables GCN5 to perform its dual functions effectively.

== Role in Transcriptional Regulation ==

The primary role of GCN5 in cells is to regulate gene expression through the acetylation of histones. This process involves the addition of an acetyl group to the [[lysine]] residues of histone proteins, which results in the relaxation of the [[chromatin]] structure and allows for the binding of [[transcription factors]] and [[RNA polymerase]] to the DNA, thereby initiating transcription.

GCN5 is also known to form part of larger protein complexes, such as the [[SAGA complex]] and the [[ADA complex]], which further enhance its transcriptional regulatory capabilities.

== Role in Disease and Therapeutic Potential ==

Given its central role in transcriptional regulation, it is not surprising that aberrations in GCN5 function have been implicated in a number of diseases, including [[cancer]], [[neurodegenerative diseases]], and [[cardiovascular diseases]]. 

In cancer, for instance, overexpression of GCN5 has been observed in several types of tumors, suggesting a potential role in tumorigenesis. Similarly, mutations in GCN5 have been linked to neurodegenerative diseases, such as [[Alzheimer's disease]] and [[Parkinson's disease]], highlighting the importance of GCN5 in maintaining neuronal health.

Due to its involvement in disease, GCN5 has emerged as a potential therapeutic target. Several small molecule inhibitors of GCN5 have been developed and are currently being evaluated for their therapeutic potential in preclinical and clinical studies.

== See Also ==

* [[Histone acetyltransferase]]
* [[Transcription (genetics)]]
* [[Epigenetics]]

== Categories ==

[[Category:Molecular biology]]
[[Category:Enzymes]]
[[Category:Gene expression]]