title: Linker histone H1.0 interacts with an extensive network of proteins found in the nucleolus.
abstract: The H1 linker histones are abundant chromatin-associated DNA-binding proteins. Recent evidence suggests that linker histones also may function through protein-protein interactions. To gain a better understanding of the scope of linker histone involvement in protein-protein interactions, we used a proteomics approach to identify H1-binding proteins in human nuclear extracts. Full-length H1.0 and H1.0 lacking its C-terminal domain (CTD) were used for protein pull-downs. A total of 107 candidate H1.0 binding proteins were identified by LC-MS/MS. About one-third of the H1.0-dependent interactions were mediated by the CTD, and two-thirds by the N-terminal domain-globular domain fragment. Many of the proteins pulled down by H1.0 were core splicing factors. Another group of H1-binding proteins functions in rRNA biogenesis. H1.0 also pulled down numerous ribosomal proteins and proteins involved in cellular transport. Strikingly, nearly all of the H1.0-binding proteins are found in the nucleolus. Quantitative biophysical studies with recombinant proteins confirmed that H1.0 directly binds to FACT and the splicing factors SF2/ASF and U2AF65. Our results demonstrate that H1.0 interacts with an extensive network of proteins that function in RNA metabolism in the nucleolus, and suggest that a new paradigm for linker histone action is in order.
authors: Department of Biochemistry and Molecular Biology, Colorado State University, 1870 Campus Delivery, Fort Collins, CO 80523-1870, USA.
authors: Anna A
authors: AA
authors: Kalashnikova
authors: Duane D
authors: DD
authors: Winkler
authors: Steven J
authors: SJ
authors: McBryant
authors: Ryan K
authors: RK
authors: Henderson
authors: Jacob A
authors: JA
authors: Herman
authors: Jennifer G
authors: JG
authors: DeLuca
authors: Karolin
authors: K
authors: Luger
authors: Jessica E
authors: JE
authors: Prenni
authors: Jeffrey C
authors: JC
authors: Hansen
mesh_terms: D002466:Cell Nucleolus / Q000378:metabolism*; D006657:Histones / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D009687:Nuclear Proteins / Q000378:metabolism*; D054730:Protein Interaction Domains and Motifs; D025941:Protein Interaction Mapping; D040901:Proteomics
chemical_list: D006657:Histones; D009687:Nuclear Proteins