Reinterpretation of the Dimerization Interface of the N-terminal Domains of STATs

Xiaomin Chen, Rashna Bhandari, Uwe Vinkemeier, Focco van den Akker, James E. Darnell Jr. and John Kuriyan

Protein Science (2003) Feb 12(2): 361-365

Abstract / Figures from the paper / PDB coordinates /


The crystal structures of the N-terminal domain (N-domain) and the core region of the STAT family of transcription factors have been determined previously (Vinkemeier et al., 1998; Chen et al., 1998). STATs can form cooperative higher order structures (tetramers or higher oligomers) while bound to DNA. The crystal packing in the STAT4 N-domain crystal structure, determined at 1.5 resolution, suggests two alternate organizations of the N-domain dimer. We now present the results of site directed mutagenesis of residues predicted to be involved at each dimer interface. Our results indicate that the dimer interface suggested earlier as being physiologically relevant is, in fact, unlikely to be so. Given the alternative model for the N-domain dimer, the ability of the N-domain to mediate interactions of two STAT dimers on DNA remains unchanged.

Illustrations from the paper. Click on the small image to get a bigger one.

PDB Coordinates

Protein Structure Coordinates and X-ray Structure Factors of the N-terminal domain of STAT4.