Reconstitution and molecular analysis of the hRad9-hHus1-hRad1 (9-1-1) DNA damage responsive checkpoint complex

A1 Originalartikel i en vetenskaplig tidskrift (referentgranskad)

Interna författare/redaktörer

Publikationens författare: Burtelow MA, Roos-Mattjus PMK, Rauen M, Babendure JR, Karnitz LM
Publiceringsår: 2001
Tidskrift: Journal of Biological Chemistry
Tidskriftsakronym: J BIOL CHEM
Volym: 276
Nummer: 28
Artikelns första sida, sidnummer: 25903
Artikelns sista sida, sidnummer: 25909
Antal sidor: 7
ISSN: 0021-9258
eISSN: 1083-351X


DNA damage activates cell cycle checkpoint signaling pathways that coordinate cell cycle arrest and DNA repair. Three of the proteins involved in checkpoint signaling, Rad1, Hus1, and Rad9, have been shown to interact by immunoprecipitation and yeast two-hybrid studies. However, it is not known how these proteins interact and assemble into a complex. In the present study we demonstrated that in human cells all the hRad9 and hHus1 and approximately one-half of the cellular pool of hRad1 interacted as a stable, biochemically discrete complex, with an apparent molecular mass of 160 kDa. This complex was reconstituted by co-expression of all three recombinant proteins in a heterologous system, and the reconstituted complex exhibited identical chromatographic behavior as the endogenous complex. Interaction studies using differentially tagged proteins demonstrated that the proteins did not self-multimerize. Rather, each protein had a binding site for the other two partners, with the N terminus of hRad9 interacting with hRad1, the N terminus of hRad1 interacting with hHus1, and the N terminus of hHus1 interacting with the C terminus of hRad9's predicted PCNA-like region. Collectively, these analyses suggest a model of how these three proteins assemble to form a functional checkpoint complex, which we dubbed the 9-1-1 complex.

Senast uppdaterad 2020-08-08 vid 05:27