1KHX: Crystal Structure Of A Phosphorylated Smad2

Ligand-induced phosphorylation of the receptor-regulated Smads (R-Smads) is essential in the receptor Ser/Thr kinase-mediated TGF-beta signaling. The crystal structure of a phosphorylated Smad2, at 1.8 A resolution, reveals the formation of a homotrimer mediated by the C-terminal phosphoserine (pSer) residues. The pSer binding surface on the MH2 domain, frequently targeted for inactivation in cancers, is highly conserved among the Co- and R-Smads. This finding, together with mutagenesis data, pinpoints a functional interface between Smad2 and Smad4. In addition, the pSer binding surface on the MH2 domain coincides with the surface on R-Smads that is required for docking interactions with the serine-phosphorylated receptor kinases. These observations define a bifunctional role for the MH2 domain as a pSer-X-pSer binding module in receptor Ser/Thr kinase signaling pathways.
PDB ID: 1KHXDownload
MMDB ID: 70935
PDB Deposition Date: 2001/12/1
Updated in MMDB: 2012/08
Experimental Method:
x-ray diffraction
Resolution: 1.8  Å
Source Organism:
Similar Structures:
Biological Unit for 1KHX: trimeric; determined by author and by software (PISA,PQS)
Molecular Components in 1KHX
Label Count Molecule
Proteins (3 molecules)
Smad2(Gene symbol: SMAD2)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB