View article

Cold Spring Harbor Symposia on Quantitative Biology, Volume LXIX.© 2004 Cold Spring Harbor Laboratory Press 0-87969-729-6/04. 289 with a single (mono) ub, or chains formed through Lys63 linkages are destined for alternate functions. These span diverse processes such as vesicular trafficking, DNA repair, and intracellular localization (Hicke 2001; Aguilar and Wendland 2003). Thus, ub and other ub-like modifications such as sumo are versatile signaling modules that are functionally reminiscent of small molecule protein posttranscriptional modifications like phosphorylation or acetylation.

Most of the histone proteins occur in ub-conjugated forms (Table 1). More than 25 years ago, histone H2A was the first protein shown to be ubiquitylated. Histones constitute the most abundant ub proteins in higher eukaryotes, including 5–15% of H2A and a few percent of H2B (Jason et al. 2002; Zhang 2003; Osley 2004 …