1G88

S4AFL3ARG515 MUTANT

Summary for 1G88

• Entry DOI: 10.2210/pdb1g88/pdb
• Related: 1DD1
• Descriptor: SMAD4 (1 entity in total)
• Functional Keywords: transcriptional factor, l3 loop mutant, transcription
• Biological source: Homo sapiens (human)
• Cellular location: Cytoplasm: Q13485
• Total number of polymer chains: 3
• Total formula weight: 88045.00

Authors

Chako, B.M.,Qin, B.,Lam, S.S.,Correia, J.J.,Lin, K. (deposition date: 2000-11-16, release date: 2000-11-29, Last modification date: 2024-02-07)

Primary citation

Chacko, B.M.,Qin, B.,Correia, J.J.,Lam, S.S.,de Caestecker, M.P.,Lin, K.
The L3 loop and C-terminal phosphorylation jointly define Smad protein trimerization.
Nat.Struct.Biol., 8:248-253, 2001

PubMed Abstract: Smad proteins mediate the transforming growth factor beta responses. C-terminal phosphorylation of R-Smads leads to the recruitment of Smad4 and the formation of active signaling complexes. We investigated the mechanism of phosphorylation-induced Smad complex formation with an activating pseudo-phosphorylated Smad3. Pseudo-phosphorylated Smad3 has a greater propensity to homotrimerize, and recruits Smad4 to form a heterotrimer containing two Smad3 and one Smad4. The trimeric interaction is mediated through conserved interfaces to which tumorigenic mutations map. Furthermore, a conserved Arg residue within the L3 loop, located near the C-terminal phosphorylation sites of the neighboring subunit, is essential for trimerization. We propose that the phosphorylated C-terminal residues interact with the L3 loop of the neighboring subunit to stabilize the trimer interaction.

PubMed: 11224571
DOI: 10.1038/84995

Experimental method

X-RAY DIFFRACTION (3 Å)