1khx

Publication Abstract from PubMed

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.

Crystal structure of a phosphorylated Smad2. Recognition of phosphoserine by the MH2 domain and insights on Smad function in TGF-beta signaling.,Wu JW, Hu M, Chai J, Seoane J, Huse M, Li C, Rigotti DJ, Kyin S, Muir TW, Fairman R, Massague J, Shi Y Mol Cell. 2001 Dec;8(6):1277-89. PMID:11779503^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.