Histone acetyltransferase 1: More than just an enzyme?

Histone acetyltransferase 1 (HAT1) is an enzyme that is likely to be responsible for the acetylation that occurs on lysines 5 and 12 of the NH2-terminal tail of newly synthesized histone H4. Initial studies suggested that, despite its evolutionary conservation, this modification of new histone H4 played only a minor role in chromatin assembly. However, a number of recent studies have brought into focus the important role of both this modification and HAT1 in histone dynamics. Surprisingly, the function of HAT1 in chromatin assembly may extend beyond just its catalytic activity to include its role as a major histone binding protein. These results are incorporated into a model for the function of HAT1 in histone deposition and chromatin assembly. This article is part of a Special Issue entitled: Histone chaperones and Chromatin assembly.

► Discussion of recent advances in our understanding of the type B histone acetyltransferase Hat1.
► Hat1 acetylates newly synthesized histone H4 at lysines 5 and 12.
► Hat1 and its complexes have been found to be major binding partners of soluble histones H3 and H4.
► A model proposed for the activities of Hat1 complexes in the process of chromatin assembly.