Surprising complexity of the Asf1 histone chaperone-Rad53 kinase interaction.
The histone chaperone Asf1 and the checkpoint kinase Rad53 are found in a complex in budding yeast cells in the absence of genotoxic stress. Our data suggest that this complex involves at least three interaction sites. One site involves the H3-binding surface of Asf11 with an as yet undefined surface of Rad53. A second site is formed by the Rad53-FHA1 domain binding to Asf1-T(270) phosphorylated by casein kinase II. The third site involves the C-terminal 21 amino acids of Rad53 bound to the conserved Asf1 N-terminal domain. The structure of this site showed that the Rad53 C-terminus binds Asf1 in a remarkably similar manner to peptides derived from the histone cochaperones HirA and CAF-I. We call this binding motif, (R/K)R(I/A/V) (L/P), the AIP box for Asf1-Interacting Protein box. Furthermore, C-terminal Rad53-F(820) binds the same pocket of Asf1 as does histone H4-F(100). Thus Rad53 competes with histones H3-H4 and cochaperones HirA/CAF-I for binding to Asf1. Rad53 is phosphorylated and activated upon genotoxic stress. The Asf1-Rad53 complex dissociated when cells were treated with hydroxyurea but not methyl-methane-sulfonate, suggesting a regulation of the complex as a function of the stress. We identified a rad53 mutation that destabilized the Asf1-Rad53 complex and increased the viability of rad9 and rad24 mutants in conditions of genotoxic stress, suggesting that complex stability impacts the DNA damage response.
Commissariat à l'Energie Atomique, iBiTec-S, Service de Biologie Intégrative et de Génétique Moléculaire, Gif-sur-Yvette F-91191, France.
Yue
Y
Jiao
Karsten
K
Seeger
Aurelie
A
Lautrette
Albane
A
Gaubert
Florence
F
Mousson
Raphael
R
Guerois
Carl
C
Mann
Françoise
F
Ochsenbein
D001665:Binding Sites; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000378:metabolism*; D064447:Checkpoint Kinase 2; D018360:Crystallography, X-Ray; D004249:DNA Damage; D056488:Histone Chaperones / Q000378:metabolism*; D006657:Histones / Q000378:metabolism; D006918:Hydroxyurea / Q000494:pharmacology; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000737:chemistry / Q000378:metabolism*; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D010455:Peptides / Q000737:chemistry / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D010768:Phosphoserine / Q000378:metabolism; D010769:Phosphothreonine / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000378:metabolism*; D055550:Protein Stability / Q000187:drug effects; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism*
C109731:ASF1 protein, S cerevisiae; D018797:Cell Cycle Proteins; D056488:Histone Chaperones; D006657:Histones; D018832:Molecular Chaperones; D050505:Mutant Proteins; D010455:Peptides; D029701:Saccharomyces cerevisiae Proteins; D010769:Phosphothreonine; D010768:Phosphoserine; D064447:Checkpoint Kinase 2; D017346:Protein Serine-Threonine Kinases; C067022:RAD53 protein, S cerevisiae; D006918:Hydroxyurea